What is Space...

The Brightest Supernova Ever

2007-05-24T14:50:00.000+02:00

The brightest stellar explosion ever recorded may be a long-sought new type of supernova, according to observations by NASA's Chandra X-ray Observatory and ground-based optical telescopes. This discovery indicates that violent explosions of extremely massive stars were relatively common in the early universe, and that a similar explosion may be ready to go off in our own galaxy.

"This was a truly monstrous explosion, a hundred times more energetic than a typical supernova," said Nathan Smith of the University of California at Berkeley, who led a team of astronomers from California and the University of Texas in Austin. "That means the star that exploded might have been as massive as a star can get, about 150 times that of our sun. We've never seen that before."

Photo 1: An artist's illustration of supernova

Astronomers think many of the first stars in the Universe were this massive, and this new supernova may thus provide a rare glimpse of how those first generation stars died. It is unprecedented, however, to find such a massive star and witness its death. The discovery of the supernova, known as SN 2006gy, provides evidence that the death of such massive stars is fundamentally different from theoretical predictions.

"Of all exploding stars ever observed, this was the king," said Alex Filippenko, leader of the ground-based observations at the Lick Observatory at Mt. Hamilton, Calif., and the Keck Observatory in Mauna Kea, Hawaii. "We were astonished to see how bright it got, and how long it lasted."

The Chandra observation allowed the team to rule out the most likely alternative explanation for the supernova: that a white dwarf star with a mass only slightly higher than the sun exploded into a dense, hydrogen-rich environment. In that event, SN 2006gy should have been 1,000 times brighter in X-rays than what Chandra detected.

Photo 2: Optical (left) and X-ray (right) images of SN 2006gy. The dimmer source at lower-left is the nucleus of the host galaxy. The brighter source at upper-right is the stellar explosion. The supernova was as bright as the entire core of a galaxy!

"This provides strong evidence that SN 2006gy was, in fact, the death of an extremely massive star," said Dave Pooley of the University of California at Berkeley, who led the Chandra observations.

The star that produced SN 2006gy apparently expelled a large amount of mass prior to exploding. This large mass loss is similar to that seen from Eta Carinae, a massive star in our galaxy, raising suspicion that Eta Carinae may be poised to explode as a supernova. Although SN 2006gy is intrinsically the brightest supernova ever, it is in the galaxy NGC 1260, some 240 million light years away. However, Eta Carinae is only about 7,500 light years away in our own Milky Way galaxy.

"We don't know for sure if Eta Carinae will explode soon, but we had better keep a close eye on it just in case," said Mario Livio of the Space Telescope Science Institute in Baltimore, who was not involved in the research. "Eta Carinae's explosion could be the best star-show in the history of modern civilization."

Photo 3: eta Carinae--a supernova waiting to happen in our own galaxy? The giant star is highlighted by diffraction spikes in this astrophoto taken by Brad Moore.

Supernovas usually occur when massive stars exhaust their fuel and collapse under their own gravity. In the case of SN 2006gy, however, astronomers think that a very different effect may have triggered the explosion. Under some conditions, the core of a massive star produces so much gamma ray radiation that some of the energy from the radiation converts into particle and anti-particle pairs. The resulting drop in energy causes the star to collapse under its own huge gravity.

After this violent collapse, runaway thermonuclear reactions ensue and the star explodes, spewing the remains into space. The SN 2006gy data suggest that spectacular supernovas from the first stars that spew their remains - rather than completely collapsing to a black hole as theorized - may be more common than previously believed.

"In terms of the effect on the early universe, there's a huge difference between these two possibilities," said Smith. "One [sprinkles] the galaxy with large quantities of newly made elements and the other locks them up forever in a black hole."

Crater for moon settlement

2007-05-23T12:21:00.000+02:00

Although ESA’s SMART-1 was smashed into the Moon in 2006, it had the opportunity to gather a tremendous amount of science. Its view of this crater in particular has given ESA scientists the feeling that they might be looking at the perfect spot for a future permanent base on the Moon.

Crater Plaskett sits very close to the Moon’s north pole. This means it’s bathed in eternal sunlight. This would provide plenty of solar energy for future explorers, and creates a predictable temperature - it’s only hot, not hot and cold. Nearby craters bathed in eternal darkness might contain large stores of water ice that could be used for air, fuel and drinking water.

Crater Plaskett might provide a good first step for exploration of the Solar System. It’s close enough that astronauts would still be able to see the Earth. Help could arrive within days, if necessary, and communications would be almost instantaneous. But it’s remote enough to help mission planners understand what would be involved for future, longer duration missions on the Moon, and eventually to Mars.

SMART-1 ended its mission on September 3, 2006, when it ran out of fuel and crashed into the lunar surface. Scientists will be studying its data and images for years.

Young Stars Hatching in Orion

2007-05-19T20:06:00.000+02:00

The latest image released from the Spitzer Space Telescope shows infant stars “hatching” in the head of Orion. Astronomers think that a supernova 3 million years ago sent shockwaves through the region, collapsing clouds of gas and dust, and beginning a new generation of star formation.

The region imaged by Spitzer is called Barnard 30, located about 1,300 light-years from Earth in the constellation of Orion. More specifically, it’s located right beside the star considered to be Orion’s head, Lambda Orionis.

Since the region is shrouded in dark clouds of gas and dust that obscure visible light images, this was an ideal target for Spitzer, which can peer right through them in the infrared spectrum. The tints of orange-red glow are dust particles warmed by the newly forming stars. The reddish-pink dots are the young stars themselves, embedded in the clouds of gas and dust.

From the Ashes of the First Stars

2007-04-29T20:37:00.000+02:00

Above, an artist's impression shows a primordial quasar as it might have been, surrounded by sheets of gas, dust, stars and early star clusters. Exacting observations of three distant quasars now indicate emission of very specific colors of the element iron. These Hubble Space Telescope observations, which bolster recent results from the WMAP mission, indicate that a whole complete cycle of stars was born, created this iron, and died within the first few hundred million years of the universe.

Image credit: NASA/ESA/ESO/Wolfram Freudling et al. (STECF)

Big Jupiter's auroras

2007-04-12T15:24:00.000+02:00

Image: X-ray auroras observed by the Chandra X-ray Observatory

Northern Lights in Alaska are big??? No way, Jupiter's auroras are much much bigger.
The purple ring traces Jupiter's X-ray auroras. Gladstone calls them "Northern Lights on steroids. They're hundreds of times more energetic than auroras on Earth."
The purple ring traces Jupiter's X-ray auroras. Gladstone calls them "Northern Lights on steroids. They're hundreds of times more energetic than auroras on Earth."
Back in 1979 Jupiter's auroras were discovered by Voyager 1 spacecraft. In the 1990s, ultraviolet cameras on the Hubble Space Telescope photographed raging lights thousands of times more intense than anything ever seen on Earth, while X-ray observatories saw auroral bands and curtains bigger than Earth itself.
Jupiter's hyper-auroras never stop. "We see them every time we look," says Gladstone. You don't see auroras in Alaska every time you look, yet on Jupiter the Northern Lights always seem to be "on." Gladstone explains the difference: On Earth, the most intense auroras are caused by solar storms. An explosion on the sun hurls a billion-ton cloud of gas in our direction, and a few days later, it hits. Charged particles rain down on the upper atmosphere, causing the air to glow red, green and purple. On Jupiter, however, the sun is not required. "Jupiter is able to generate its own lights," says Gladstone.
The process begins with Jupiter's spin: The giant planet turns on it axis once every 10 hours and drags its planetary magnetic field around with it. As any science hobbyist knows, spinning a magnet is a great way to generate a few volts—it's the basic principle of DC motors. Jupiter's spin produces 10 million volts around its poles.
The February 2007 dataset may hold important clues. "Chandra observed the auroras for 15 hours, and we weren't the only ones watching," he says. The Hubble Space Telescope, the FUSE satellite, XMM-Newton (a European X-ray observatory), the New Horizons spacecraft and many ground-based observatories were all taking data at the same time. The campaign was timed to coincide with New Horizons flyby of Jupiter—a slingshot maneuver designed to increase its velocity en route to Pluto.

"Jupiter's auroras have never been observed by so many telescopes at once," says Gladstone. "I'm really excited by these data, and the analysis is just beginning."

nebula NGC 2440 with Sun-like star

2007-02-14T22:21:00.000+01:00

This image is taken by NASA/ESA Hubble Space Telescope! It shows the colorful "last hurrah" of a star like Sun. The star is ending its life. The star, called white dwarf, is the with dot in the center. The planetary nebula in this image is called NGC 2440. The white dwarf at the center of NGC 2440 is one of the hottest known, with a surface temperature of more than 200,000 degrees Celsius.

Credit: NASA, ESA, and K. Noll (STScI)

Did you know?

2006-12-27T21:18:00.000+01:00

Some NASA facts

Four days after it was launched, the Deep Space 1 spacecraft was about 1,000,000 kilometers (about 600,000 miles) from Earth. To fly that far in a jet, you would have to fly for 6 weeks without stopping!

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To communicate with distant spacecraft, NASA's Deep Space Network uses antenna with a diameter of up to 70 meters (230 feet). That is almost as big as a football field.

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It's a small world. More than 1,000 Earths would fit into Jupiter's vast sphere.

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Saturn's beautiful rings are not solid. They are made up of particles of ice, dust and rock -- some as tiny as grains of sand, some much larger than skyscrapers.

How the Really Big Stars Form

2006-10-17T21:30:00.000+02:00

Astronomers think they’ve got a handle on how Sun-sized stars come together. But the formation of the largest stars - more than 10 times the mass of the Sun - still puzzle astronomers. New observations on a 20 solar mass star have revealed that these giant stars maintain a torus of material around themselves. They can continuously feed from this “doughnut” of material, while powerful jets of radiation pour from their poles. The material can continue gathering onto the star while avoiding this radiation, which would normally blast it back into space.
Astronomers using the National Science Foundation’s Very Large Array (VLA) radio telescope have discovered key evidence that may help them figure out how very massive stars can form.
“We think we know how stars like the Sun are formed, but there are major problems in determining how a star 10 times more massive than the Sun can accumulate that much mass. The new observations with the VLA have provided important clues to resolving that mystery,” said Maria Teresa Beltran, of the University of Barcelona in Spain.
Beltran and other astronomers from Italy and Hawaii studied a young, massive star called G24 A1 about 25,000 light-years from Earth. This object is about 20 times more massive than the Sun. The scientists reported their findings in the September 28 issue of the journal Nature.
Stars form when giant interstellar clouds of gas and dust collapse gravitationally, compacting the material into what becomes the star. While astronomers believe they understand this process reasonably well for smaller stars, the theoretical framework ran into a hitch with larger stars.
“When a star gets up to about eight times the mass of the Sun, it pours out enough light and other radiation to stop the further infall of material,” Beltran explained. “We know there are many stars bigger than that, so the question is, how do they get that much mass?”
One idea is that infalling matter forms a disk whirling around the star. With most of the radiation escaping without hitting the disk, material can continue to fall into the star from the disk. According to this model, some material will be flung outward along the rotation axis of the disk into powerful outflows.
“If this model is correct, there should be material falling inward, rushing outward and rotating around the star all at the same time,” Beltran said. “In fact, that’s exactly what we saw in G24 A1. It’s the first time all three types of motion have been seen in a single young massive star,” she added.
The scientists traced motions in gas around the young star by studying radio waves emitted by ammonia molecules at a frequency near 23 GHz. The Doppler shift in the frequency of the radio waves gave them the information on the motions of the gas. This technique allowed them to detect gas falling inward toward a large “doughnut,” or torus, surrounding the disk presumed to be orbiting the young star.
“Our detection of gas falling inward toward the star is an important milestone,” Beltran said. The infall of the gas is consistent with the idea of material accreting onto the star in a non-spherical manner, such as in a disk. This supports that idea, which is one of several proposed ways for massive stars to accumulate their great bulk. Others include collisions of smaller stars.
“Our findings suggest that the disk model is a plausible way to make stars up to 20 times the mass of the Sun. We’ll continue to study G24 A1 and other objects to improve our understanding,” Beltran said.
Beltran worked with Riccardo Cesaroni and Leonardo Testi of the Astrophysical Observatory of Arcetri of INAF in Firenze, Italy, Claudio Codella and Luca Olmi of the Institute of Radioastronomy of INAF in Firenze, Italy, and Ray Furuya of the Japanese Subaru Telescope in Hawaii.
The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Original Source: NRAO News Release

Solar System and white star

2006-09-27T13:54:00.000+02:00

Our solar system comparing to big white star

Hubble photo

2006-09-27T13:51:00.000+02:00

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Description: This one of the NASA Hubble Telescope photos...

Sun with satellite

2006-08-25T14:09:00.000+02:00

Launched on Dec. 2, 2005, SOHO observes the sun's deep interior and also its interactions all the way out to Earth's orbit and beyond, where the magnetized solar wind of atomic particles sweeps through interplanetary space.

Soyuz

2006-08-25T14:06:00.000+02:00

Carrying the Expedition 12 crew, a Soyuz TMA-7 that launched from the Baikinour Cosmodrome in Kazakhstan approaches the International Space Station.

Image credit: NASA

More about comets

2006-08-25T14:04:00.001+02:00

A comet is a minor planet made up of rock, dust and ice. It originates from a cloud of debris remaining from the condensation of the solar nebula. Comets are unique because they are created in the outer solar system, and are greatly affected by the planets they pass. While a comet is orbiting, its path is constantly being altered as it nears surrounding planets. These changes in orbit can send it on a path approaching the sun, where it will burn up, or can be cast completely out of the solar system.
The tail of a comet is actually called the coma, which is composed of gas and dust streams. When a comet passes through the inner solar system, the sun lights up these streams so that we are able to see it. This is how we have been able to see Halley’s Comet from Earth.
The orbital periods of comets vary, but have been divided into three categories: Short period comets; long period comets; and Single-apparition comets. While Short period comets orbit for 200 years or less, long period comets are bound by gravity to the sun, and remain much longer. Single-apparition comets have unusual orbits and are thrown out of the solar system forever.

What are black holes

2006-08-25T14:04:00.000+02:00

The anomalous black holes are concentrated areas of mass so immense, that the mammoth force of gravity denies anything within a certain area around it from passing. This area is called the event horizon of a black hole.
We have given black holes their name because light inside the event horizon can never be seen by mankind, or any outside observer. We believe that black holes in space are created by the collapse of a red super giant star. As these stars reach the end of their lives, an imbalance of inward and outward pressure forces the star to collapse.
Information on black holes is limited, though numerous schools of theory exist. We know black holes exist not because we can see them, but because of the impact they have on the space around them.
Scientists like Karl Schwarzschild, Jayant Narlikar and Stephen Hawking have built upon ideas from Einstein and others to offer theories on black holes. And yet, they remain an enigma. Because extensive, proven black holes information is scarce, they remain a constant area of intrigue and curiosity.

Something more about our solar system

2006-08-25T13:58:00.000+02:00

The solar system is the home to the sun, nine planets including the Earth, the 158 known moons that orbit those planets, as well as a countless number of other celestial bodies that exist throughout this vast space. Such celestial bodies include things like asteroids, meteoroids and comets.
Though the events leading up to the formation of the solar system are still being debated, is it believed to be more than 4.6 billion years old!
The word "solar" is derived from the Latin word for sun, Sol, leading to the term solar system, or the system of the sun. The planets that orbit the sun within the solar system include Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and the smallest planet of Pluto. Jupiter is by far the largest with an overall mass of more than three times that of the Earth. The sun itself makes up an estimated 99.86% of the solar system’s total mass.

From 9 to 12

2006-08-25T11:51:00.000+02:00

Image: The 12 planets under the newly proposed IAU definition. Planet sizes are shown to scale but their orbital distances are not to scale. Credit: IAU/Martin Kornmesser

According to new definition proposed by the International Astronomical Union (IAU) we now have 12 planets in our solar system.
* The asteroid Ceres, which is round, would be recast as a dwarf planet in the new scheme
* Pluto would remain a planet. It's moon Charon would become planet, and both would be called "plutons"
* A Pluto sized object, 2003 UB313 would also be called a pluton

The discoverer of the 12th planet, Mike Brown, thinks that idea of 12 planets is "lousy". He also says that accourding to the new definition there are already 53 planets in our solar system, and much more to be discovered.

The definition says that all round objects orbiting stars will be called planets.
"A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet."

Image: In proposing a new planet definition, the International Astronomical Union put 12 objects on a watch list of candidates that need further study. They are shown here to scale with Earth. Credit: IAU/Martin Kornmesser

Universe could be larger

2006-08-13T10:54:00.000+02:00

Astronomers recently calculated the distance to the relatively nearby galaxy M33 (The Triangulum Galaxy) as being about 15% further than previously estimated. They analyzed the distance using several telescopes, fine tuning their instruments very carefully. This measurement means that the Hubble constant - which astronomers use to measure distances in the Universe - could be off as well. The Universe might actually be 15% larger than previously believed.

Right start in astronomy

2006-06-11T23:13:00.000+02:00

Too many newcomers to astronomy get lost in dead ends and quit in frustration. It shouldn't be that way. Alan M. MacRobert at skyandtelescope.com explains how simple, easy and interesting can astornomy be! You just have to start right.

Some of the tips are:

1. Learn the sky with the unaided eye.
2. Ransack your public library.
3. Thinking telescope? Start with binoculars.
4. Dive into maps and guidebooks.
5. Keep an astronomy diary.
6. Seek out other amateurs.
7. When it's time for a telescope, plunge in deep.
8. Lose your ego.
9. Relax and have fun.

For more details visit skyandtelescope

Our solar system

2006-06-08T15:15:00.000+02:00

Our solar system is part of the Milky Way galaxy, a spiral galaxy with a diameter of about 100,000 light years containing about 200 billion stars. The solar system comprises our Sun and the retinue of celestial objects gravitationally bound to it. Traditionally, this is said to consist of the Sun, nine planets and their 158 currently known moons; however, a large number of other objects, including asteroids, meteoroids, planetoids, comets, and interplanetary dust, orbit the Sun as well. The Sun is a main sequence G2 star that contains 99.86% of the system's known mass. The point at which solar system ends and interstellar space begins is not precisely defined, since its outer boundaries are delineated by two separate forces: the solar wind and the Sun's gravity.

The current hypothesis of solar system formation is the nebular hypothesis, first proposed in 1755 by Immanuel Kant and independently formulated by Pierre-Simon Laplace. It states the solar system was formed from a gaseous cloud called the solar nebula. It had a diameter of 100 AU and was 2-3 times the mass of the Sun. Over time, a disturbance, possibly a nearby supernova, sent shock waves into space, which squeezed the nebula, pushing more and more of its matter inward until gravitational forces overcame its internal gas pressure and it began to collapse. As the nebula collapsed, it decreased in size, which in turn caused it to spin faster to conserve angular momentum. And as the competing forces associated with gravity, gas pressure, magnetic fields, and rotation acted on it, the contracting nebula began to flatten into a spinning pancake shape with a bulge at the center.

When the nebula further condensed, a protostar was formed in the middle. This system was heated by friction of the rocks colliding into each other. Lighter elements such as hydrogen and helium evaporated out of the centre and migrated to the disc's edges, thus concentrating heavier elements to form dust and rocks in the centre. These heavier elements clumped together to form planetesimals and protoplanets. In the outer regions of this solar nebula, ice and volatile gases were able to survive, and as a result, inner planets are rocky and the massive outer planets captured large amounts of lighter gases, such as hydrogen and helium.

After 100 million years, the pressures and densities of hydrogen in the centre of the collapsed nebula became great enough for the protosun to sustain thermonuclear fusion reactions. As a result of this, hydrogen was converted to helium, and a great amount of heat was released.

During that time, the protostar turned into the Sun and the protoplanets and planetesimals were transformed into planets. All of the planets formed in a relatively short time of a few million years.

Scientists estimate that the solar system is 4.6 billion years old. To calculate this figure, they examine an unstable element, which is subject to radioactive decay. By observing how much this element has decayed, they can calculate how old this element is. The oldest rocks on earth are approximately 3.9 billion years old, however it is hard to find these rocks as the earth has been thoroughly resurfaced. To estimate the age of the solar system, scientists must find rocks from space, such as meteorites – which are formed during the early condensation of the solar nebula. The oldest meteorite was found to have an age of 4.6 billion years, hence the solar system must be at least 4.6 billion years old.

Titan on the side

2006-06-08T13:57:00.000+02:00

Titan is the largest Saturn's moon, it peaks out from under the planet's rings of ice
This view looks toward Titan (5,150 kilometers, or 3,200 miles across) from slightly beneath the ringplane. The dark Encke gap (325 kilometers, or 200 miles wide) is visible here, as is the narrow F ring.
Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were taken with the Cassini spacecraft narrow-angle camera on April 28, 2006 at a distance of approximately 1.8 million kilometers (1.1 million miles) from Titan.

Image credit: NASA/JPL/Space Science Institute

Skylab

2006-06-08T13:54:00.000+02:00

This time exposure photograph of the Mobile Service Structure makes the structure apprear as a streak of light as it moves away from the Skylab 4 space vehicle the night before the launch.
Skylab 4 launched on Nov. 16, 1973. The crew -- Commander Gerald Carr, Mission Pilot William Pogue and Edward Gibson -- spent 84 days aboard the station.

Image credit: NASA (Full Resolution)

SuitSat - new satellite

2006-06-08T13:45:00.000+02:00

Using a simple police scanner or ham radio, you can listen to a disembodied spacesuit circling Earth.
One of the strangest satellites in the history of the space age was in orbit! The spacesuit is the satellite -- "SuitSat" for short.
SuitSat is a Russian brainstorm. Old spacesuits can be turned into useful satellites. SuitSat is a first test of that idea.

Photo: ISS astronaut Mike Finke spacewalks in a Russian Orlan spacesuit in 2004. SuitSat will have no one inside.
Spacesuit was equipped with three batteries, a radio transmitter and internal sensors to measure temperature and battery power. As SuitSat circled Earth, it transmited its condition to the ground.
SuitSat could be heard by anyone on the ground. All you need is an antenna and a radio receiver that you can tune to 145.990 MHz FM. A police band scanner or a hand-talkie ham radio would work just fine. Students, scouts, teachers and ham radio operators were able to tune in.
Using Science@NASA’s J-PASS utility you could find out when will SuitSat orbit over your city. All you need to enter is you zip code.

Photo: Tune your FM radio to 145.990 MHz.
When you point antena you could hear:
SuitSat transmits for 30 seconds, pauses for 30 seconds, and then repeats. "This is SuitSat-1, RS0RS”
Suitsat 'talked' using a voice synthesizer. It's pretty amazing.

Huge storms on Jupiter

2006-06-05T23:58:00.000+02:00

Two biggest storms in solar system are about to happened!

Storm #1 is the Great Red Spot, twice as wide as Earth itself, with winds blowing 350 mph. The behemoth has been spinning around Jupiter for hundreds of years.

Storm #2 is Oval BA, also known as "Red Jr.," a youngster of a storm only six years old. Compared to the Great Red Spot, Red Jr. is half-sized, able to swallow Earth merely once, but it blows just as hard as its older cousin.

Photo: Jupiter's two red spots
Amy Simon-Miller of the Goddard Space Flight Center said that closest approach is going to be on the 4th of July. Two storms are converging. Amy Simon-Miller is monitoring the storms using the Hubble Space Telescope. "The Great Red Spot is not going to 'eat' Oval BA or anything like that." But the storms' outer bands will pass quite close to one another—and no one knows exactly what will happen.

Photo: Red Oval BA
The color of the Great Red Spot itself is a mystery. A popular theory holds that the storm dredges up material from deep inside Jupiter's atmosphere, lifting it above the highest clouds where solar ultraviolet rays turn "chromophores" (color-changing compounds) red. A beefed-up Oval BA could suddenly do the same.

Some amateur astronomers are already monitoring this event

Stars and Planets Alignment

2006-06-04T16:51:00.000+02:00

Mark you calendar: June 7th, June 15th and June 17th. Three sunsets, three planets and a star cluster – good way to end the day.
Something remarkable is about to happen in the evening sky. Three planets and a star cluster are converging for a close encounter you won't want to miss.

June 7th: If you are Star Trek fan, make the Vulcan "Live Long and Prosper" sign with your right hand. Hold it at arm's length. By Wednesday, June 7th, both Mars and Saturn will fit inside the "V"

June 15th: This is special night. Mars will pass directly in front of the Beehive. See this with binoculars or with small telescope. Red Mars is 16 times brighter than the surrounding stars. It’ll look like a red supernova has gone off inside the cluster.
More in June 15th, Mercury leaps out of the glare of the Sun, soaring into the evening sky not far from Saturn and Mars. Mercury is easy to see even from over-lit cities.

June 17th: Mars and Saturn draw so close together you might think they are going to collide (of course they won’t). Stick out your pinky and hold it at arm's length. The two planets will fit behind the tip with room to spare. Mercury, meanwhile, hovers just below.

New Moons of Pluto

2006-06-03T16:57:00.000+02:00

Astronomers using NASA’s Hubble Space Telescope discover that Pluto, the ninth planet is our solar system, may have not one, but three moons.

Picture: An artist's concept of the Pluto system as seen from the surface of one of the candidate moons.

Pluto was discovered in 1930. It is 3 billion miles away form sun in the heart of the Kupiter Belt, a vast region of icy, rocky bodies beyond Neptune’s orbit. Charon, Pluto’s moon, was discovered in 1978.
"If, as our new Hubble images indicate, Pluto has not one, but two or three moons, it will become the first body in the Kuiper Belt known to have more than one satellite," said Hal Weaver of the Johns Hopkins Applied Physics Laboratory, Laurel, Md. He is co-leader of the team that made the discovery.
New moons are 44,000 km away from Pluto, and that is two or three times more far than Pluto – Charon
These are tiny moons. Their estimated diameters lie between 64 and 200 kilometers. Charon, for comparison, is about 1170 km wide, while Pluto itself has a diameter of about 2270 km.
Two new moon candidate are seen with Hubble on May 15, 2005. Three days later, Hubble looked at Pluto again. The two objects were still there and appeared to be moving in orbit around Pluto
The team look for any other moons around Pluto but didn’t find nothing.

Picture: Hubble Space Telescope images taken in May 2005 show the candidate moons apparently rotating counterclockwise around Pluto.

Earth's climate

2006-05-26T11:36:00.000+02:00

Satellite data of Earth give scientists more information about conditions on Earth...

Leo A galaxy

2006-05-25T20:09:00.000+02:00

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Credit: Subaru Telescope, NAOJ

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Leo A galaxy is a member of the Local Group of galaxies that includes the Milky Way. This galaxy is 2.6 million light-years away form us.

Extreme Planets

2006-05-24T20:05:00.000+02:00

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Credit: NASA
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Pulsars are rapidly rotating neutron stars, which are the collapsed cores of exploded massive stars.
Three pulsar planets are shown in this picture.

Sun Image

2006-05-23T23:32:00.000+02:00

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Our Sun is G2 star

Diameter: 1,390,000 km
Temperature: 5800 K (on surface) and 15,600,000 K (core)
Mass: 1.989 e³⁰ kg

Tags: Sun, Solar, Photo, Star.

The Reflection Nebula in Orion

2006-05-21T20:49:00.000+02:00

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Credit: Nasa

Planets of Solar System

2006-05-21T10:11:00.000+02:00

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Planets:
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
Pluto is not shown

Jupiter's moons

2006-05-20T22:56:00.000+02:00

Cresent Europa

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Credit: NASA
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This is Jupiter's moon Europa. Picture is taken by Voyager 2. Surface of this moon in ice (bright areas) and rock (darkened areas).

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Io

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Credit: NASA
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Io is Jupiter's moon. This photo is taken on July 3, 1999.

Tadpole's Tidal Tail

2006-05-20T15:23:00.000+02:00

This image is tak with the Hubble Telescope. It shows far galaxies and spiral galaxy Arp 188 better known as Tadpole Galaxy. It is 420 million light-years distant toward the northern constellation Draco. It's tail is about 280 thousand light-years long.
Tadpole Galaxy will lose it tail as it grows older.

The Da Vinci Glow

2006-05-11T14:52:00.000+02:00

Da Vinci isn’t just Mona Lisa. Da Vinci discovered Earthshine…

Leonardo explained “ashen glow” or "the old Moon in the new Moon's arms” how humans called this apperance for thousands of years. Up to 16th century noone knew how to explain this, until Da Vinci figured it out

The source of Earthshine are clouds. Oceans are also source of Earthshine but not the primary. Earth is shining because it reflects sunlight. Clouds are the first who do reflecting. Interesting is that when Apollo astronauts looked at Earth, the clouds were bright and the oceans were dark.

Solar minimum

2006-05-07T11:29:00.000+02:00

How to prove that Sun spins?
It is really simply.
Step 1: Look at the sun. You can use internet to look at the sun.
Step 2: Sketch the sunspots
Step 3: Do step 2 daily. After few days you will see that sunspots are moving. One complete turn sun perform every 27 days.

A picture of the sun taken Feb. 10, 2006, by the Solar and Heliospheric Observatory (SOHO).

This is how Galileo prove that sun spins in 1610.

In this time it is not possible to prove that sun spins! There are no sunspots. For almost entire February 2006 the sun was blank. If Galileo look at the sun now he would have been disappointed. There are no sunspots, no spin, no discovery.

What is all this? David Hathaway (NASA solar Physicist) explains: “solar minimum has arrived.”

Every 11 year sunspots came and go. This is sunspot cycle. At sunspots maximum there are spots big as Jupiter, and in sunspots minimum period there is no single spot.

This year is minimum so there are no sptos on sun.

No sunspots means low solar activity.

Galileo look at sin in 1610. and that year was close to to a maximum sunspot cycle. He was lucky. Also Chinese astronomers had reported spots on sun in 28 BC. The nature of spots in mystery. Maybe they are satellites, dark clouds or something else.

A sketch of the sun made by Galileo in June 1613.

Eyes In The Sky

2006-05-07T11:26:00.000+02:00

These icy blue eyes are two merging galaxies. One is NGC 2207 and other IC 2163. These two galaxies met about 40 million years ago. All this is happening 140 million light-years away from us :)

Jupiter's Great Red Spot

2006-05-06T16:02:00.001+02:00

Voyager 1 captured this photo of the Great Red Spot. The Great Red Spot is a storm on Jupiter. It is like the worst hurricanes on Earth. It is so large that three Earths can fit inside it.

The Earth and Moon

2006-05-06T16:02:00.000+02:00

Spacecraft Galileo took pictures of Earth and Moon in 1992.
Photos of Earth and Monn are combined in this picture.

Planet Named George

2006-05-06T15:08:00.000+02:00

Ancient people have spent countless hours watching Mercury, Venus, Mars, Jupiter and Saturn. Can you belive they missed one!

There is and sixth planet you can see without telescope, a planet named George!

“George” is glowing like an aqua-blue star of 6th magnitude. It is four times bigger than Earth, it has more than 30 moon and dozen thin rings. George make one full spin around Earth in 84 years.

George is better known as Uranus.

William Herschel, English astronomer, discovered “George” in 1781. He named it the Georgium Sidus (the Georgian Planet) in honor of his king, King George III. Later George was re-named Uranus, like the Greek god of sky.

Uranus had been mistaken many times for a star. John Flamsteed (astronomer) cataloged it as 34 Tauri, the 34th star of Taurus the Bull. Uranus is too far from the sun and it looks like a star without using telescope. Also Uranus moves so slowly.

Light and Shadow in the Carina Nebula

2006-05-05T20:06:00.000+02:00

Previously unseen details of a mysterious, complex structure within the Carina Nebula (NGC 3372) are revealed by this image of the "Keyhole Nebula," obtained with NASA's Hubble Space Telescope.

Saturn's Subtle Spectrum

2006-05-04T23:36:00.000+02:00

Dreamy colors ranging from pale rose to butterscotch to sapphire give this utterly inhospitable gas planet a romantic appeal. Shadows of the rings caress the northern latitudes whose blue color is presumed to be a seasonal effect. Enceladus (505 kilometers, or 314 miles across) hugs the ringplane right of center. Image Credit: NASA/JPL/Space Science Institute

Lunar Dust Buster

2006-05-04T19:33:00.000+02:00

Lunar Dust Buster
Ever get a fragile item packed in a box filled with Styrofoam peanuts? Plunge your hands into the foam peanuts to search for the item, and when you pull it out foam peanuts are clinging to your arms. Try to brush them off, and they won't fall off—instead, they seem to hop away, only to cling to your legs or elsewhere. The smaller the peanuts, the more tenacious they seem. In fact, if you break a foam peanut into bits, the tiny lightweight bits are almost impossible to brush off. This behavior is classic static cling. It's also the behavior of lunar—and possibly also Martian—dust. The dozen Apollo astronauts who landed on the Moon between 1969 and 1972 found moondust to be an unexpected challenge. Not only was it so abrasive that it wore partially through the outer gloves of their space suits, but also it stuck to everything. The more they tried to brush it away, the more it worked its way into the space suits' fabric.

A tiny, jagged speck of moondust. Micro-photograph courtesy of David McKay, NASA/JSC.

Part of the dust's tenacious clinging was due to the sharp, irregular shapes of individual dust grains, formed by millions of years of meteorite impacts that repeatedly melted rocks into glass and then broke the glassy rocks into powdered glass. The particles' jagged edges were almost like claws that hooked into things like microscopic burrs. But another reason was the dust's electrostatic charge. On the Moon, harsh, unshielded ultraviolet rays from the Sun have enough energy to kick electrons out of the upper layers of the regolith (soil), giving the surface of each dust particle a net positive charge. The smaller the particles, the less their mass and the greater their charged surface area, so the more they clung—just like Styrofoam peanuts broken into small bits. A team led by Carlos I. Calle (lead scientist at NASA's Electrostatics and Surface Physics Laboratory at Kennedy Space Center), however, has used a bit of intellectual judo to figure out a way to take advantage of the dust grains' electrostatic charge to repel them. In fact, they've come up with a new application of an old idea. "In the 1970s, electrical engineering professor Senichi Masuda of the University of Tokyo—well-known as a pioneer in electrostatics—came up with the 'electric curtain'," Calle recalls. Masuda, not even thinking about the Moon or Mars, was working on air pollution filters. Because smog particles are often charged, Masuda came up with a prototype of what he called the electric curtain. Essentially, the electric curtain was a series of parallel electrodes—thin copper wires—spaced roughly a centimeter (half an inch) apart in a circuit board. To them, Masuda applied alternating current, such as that from an ordinary wall socket. The word "alternating" refers to the fact that the electrons in the wires are quickly—60 times a second in the United States, 50 times a second in Europe—made to move forward and backward along the wire, instead of just in one direction as in the direct current from a battery.

Prof. Senichi Masuda's diagram of the original "electric curtain," circa 1971.

But instead of providing the same alternating current to all the parallel electrodes at once, Masuda did something ingenious. He slightly delayed the onset of the current to each successive electrode. That slight delay made the electromagnetic field of each electrode to be out of phase with its neighbors, creating an electromagnetic wave that rapidly traveled horizontally across the surface on which the electrodes lay. Moreover, any charged particles lying on the surface got lifted and moved by that traveling electromagnetic wave, as if they were surfers being pushed along by an ocean wave. Fast forward to the present: After seeing how Martian dust that collected on the solar panels of Mars Pathfinder deprived it of electric power and impaired performance, Calle and his collaborators began wondering if the electric curtain could be adapted to keep solar panels on the Moon and Mars dust-free. After all, he reasoned, "human and robot astronauts can't always be cleaning windows." To let sunlight through, however, the device would need transparent electrodes. So instead of using copper wires, Calle and his colleagues made electrodes out of indium titanium oxide (ITO), transparent semiconducting oxides "that are now a mature technology, used in the touch screens of PDAs (personal digital assistants)," Calle explains. They also moved the electrodes closer together—just a few millimeters apart. The result was a transparent film that "is flexible, like a sheet of vinyl," that they call an electrodynamic dust shield.

Calle's device rapidly throws off simulated martian dust in a laboratory test at the Kennedy Space Center.

When the transparent dust shield was covered with simulated lunar or Martian dust (which is mostly ground-up volcanic ash and cinders from terrestrial volcanoes) and put in a vacuum chamber that was then pumped down to the rarefied atmospheric pressure of Mars or the Moon, it worked like a champ. Most of the dust was thrown off to the side in seconds. None of the simulated lunar and Martian soils, however, contains either the pure iron or shards of glass found in real moondust. This difference might affect the dust shield's effectiveness. "I'm hoping to try the experiment again with a vial of actual lunar dust," he says. While Calle is optimistic about the dust shield's effectiveness for large flat or gently curved surfaces such as solar panels and the visors of astronauts' helmets, "folds in the fabric of a space suit are more challenging," he says. "ITOs are flexible, but after a point will break." He's also working to fine-tune the voltage, frequency, phase, and other electrical properties of the traveling electromagnetic wave to repel the greatest amount of dust. And he's curious to see how it would behave in lower gravity. There's much work to be done, says Calle, but one day his device might draw the curtain on the troubles with moondust.

Are We Alone in the Universe?

2006-04-27T13:55:00.000+02:00

Are We Alone in the Universe?
Richard A. Kerr

Alone, in all that space? Not likely. Just do the numbers: Several hundred billion stars in our galaxy, hundreds of billions of galaxies in the observable universe, and 150 planets spied already in the immediate neighborhood of the sun. That should make for plenty of warm, scummy little ponds where life could come together to begin billions of years of evolution toward technology-wielding creatures like ourselves. No, the really big question is when, if ever, we'll have the technological wherewithal to reach out and touch such intelligence. With a bit of luck, it could be in the next 25 years.

Workers in the search for extraterrestrial intelligence (SETI) would have needed more than a little luck in the first 45 years of the modern hunt for like-minded colleagues out there. Radio astronomer Frank Drake's landmark Project Ozma was certainly a triumph of hope over daunting odds. In 1960, Drake pointed a 26-meter radio telescope dish in Green Bank,West Virginia, at two stars for a few days each. Given the vacuum-tube technology of the time, he could scan across 0.4 megahertz of the microwave spectrum one channel at a time.

Almost 45 years later, the SETI Institute in Mountain View,California, completed its 10-year-long Project Phoenix. Often using the 350-meter antenna at Arecibo, Puerto Rico, Phoenix researchers searched 710 star systems at 28 million channels simultaneously across an 1800-megahertz range. All in all, the Phoenix search was 100 trillion times more effective than Ozma was.

Besides stunning advances in search power, the first 45 years of modern SETI have also seen a diversification of search strategies. The Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations (SERENDIP) has scanned billions of radio sources in the Milky Way by piggybacking receivers on antennas in use by observational astronomers, including Arecibo. And other groups are turning modest-sized optical telescopes to searching for nanosecond flashes from alien lasers.

Listening for E.T. The SETI Institute is deploying an array of antennas and tying them into a giant "virtual telescope."
CREDIT: SETI

Still, nothing has been heard. But then, Phoenix, for example, scanned just one or two nearby sunlike stars out of each 100 million stars out there. For such sparse sampling to work, advanced, broadcasting civilizations would have to be abundant, or searchers would have to get very lucky.

To find the needle in a galaxy-size haystack, SETI workers are counting on the consistently exponential growth of computing power to continue for another couple of decades. In northern California, the SETI Institute has already begun constructing an array composed of individual 6-meter antennas. Ever-cheaper computer power will eventually tie 350 such antennas into "virtual telescopes," allowing scientists to search many targets at once. If Moore's law--that the cost of computation halves every 18 months--holds for another 15 years or so, SETI workers plan to use this antenna array approach to check out not a few thousand but perhaps a few million or even tens of millions of stars for alien signals. If there were just 10,000 advanced civilizations in the galaxy, they could well strike pay dirt before Science turns 150.

The technology may well be available in coming decades, but SETI will also need money. That's no easy task in a field with as high a "giggle factor" as SETI has. The U.S. Congress forced NASA to wash its hands of SETI in 1993 after some congressmen mocked the whole idea of spending federal money to look for "little green men with misshapen heads," as one of them put it. Searching for another tippy-top branch of the evolutionary tree still isn't part of the NASA vision. For more than a decade, private funding alone has driven SETI. But the SETI Institute's planned $35 million array is only a prototype of the Square Kilometer Array that would put those tens of millions of stars within reach of SETI workers. For that, mainstream radio astronomers will have to be onboard--or we'll be feeling alone in the universe a long time indeed.

What Is the Universe Made Of?

2006-04-27T13:41:00.000+02:00

What Is the Universe Made Of?
Charles Seife

Every once in a while, cosmologists are dragged, kicking and screaming, into a universe much more unsettling than they had any reason to expect. In the 1500s and 1600s, Copernicus, Kepler, and Newton showed that Earth is just one of many planets orbiting one of many stars, destroying the comfortable Medieval notion of a closed and tiny cosmos. In the 1920s, Edwin Hubble showed that our universe is constantly expanding and evolving, a finding that eventually shattered the idea that the universe is unchanging and eternal. And in the past few decades, cosmologists have discovered that the ordinary matter that makes up stars and galaxies and people is less than 5% of everything there is. Grappling with this new understanding of the cosmos, scientists face one overriding question: What is the universe made of?

This question arises from years of progressively stranger observations. In the 1960s, astronomers discovered that galaxies spun around too fast for the collective pull of the stars' gravity to keep them from flying apart. Something unseen appears to be keeping the stars from flinging themselves away from the center: unilluminated matter that exerts extra gravitational force. This is dark matter.

Over the years, scientists have spotted some of this dark matter in space; they have seen ghostly clouds of gas with x-ray telescopes, watched the twinkle of distant stars as invisible clumps of matter pass in front of them, and measured the distortion of space and time caused by invisible mass in galaxies. And thanks to observations of the abundances of elements in primordial gas clouds, physicists have concluded that only 10% of ordinary matter is visible to telescopes.

In the dark. Dark matter holds galaxies together; supernovae measurements point to a mysterious dark energy.
CREDIT: HIGH-Z SUPERNOVA SEARCH TEAM/HST/NASA

But even multiplying all the visible "ordinary" matter by 10 doesn't come close to accounting for how the universe is structured. When astronomers look up in the heavens with powerful telescopes, they see a lumpy cosmos. Galaxies don't dot the skies uniformly; they cluster together in thin tendrils and filaments that twine among vast voids. Just as there isn't enough visible matter to keep galaxies spinning at the right speed, there isn't enough ordinary matter to account for this lumpiness. Cosmologists now conclude that the gravitational forces exerted by another form of dark matter, made of an as-yet-undiscovered type of particle, must be sculpting these vast cosmic structures. They estimate that this exotic dark matter makes up about 25% of the stuff in the universe--five times as much as ordinary matter.

But even this mysterious entity pales by comparison to another mystery: dark energy. In the late 1990s, scientists examining distant supernovae discovered that the universe is expanding faster and faster, instead of slowing down as the laws of physics would imply. Is there some sort of antigravity force blowing the universe up?

All signs point to yes. Independent measurements of a variety of phenomena--cosmic background radiation, element abundances, galaxy clustering, gravitational lensing, gas cloud properties--all converge on a consistent, but bizarre, picture of the cosmos. Ordinary matter and exotic, unknown particles together make up only about 30% of the stuff in the universe; the rest is this mysterious anti-gravity force known as dark energy.

This means that figuring out what the universe is made of will require answers to three increasingly difficult sets of questions. What is ordinary dark matter made of, and where does it reside? Astrophysical observations, such as those that measure the bending of light by massive objects in space, are already yielding the answer. What is exotic dark matter? Scientists have some ideas, and with luck, a dark-matter trap buried deep underground or a high-energy atom smasher will discover a new type of particle within the next decade. And finally, what is dark energy? This question, which wouldn't even have been asked a decade ago, seems to transcend known physics more than any other phenomenon yet observed. Ever-better measurements of supernovae and cosmic background radiation as well as planned observations of gravitational lensing will yield information about dark energy's "equation of state"--essentially a measure of how squishy the substance is. But at the moment, the nature of dark energy is arguably the murkiest question in physics--and the one that, when answered, may shed the most light.

Tycho Brahe Planetarium

2006-04-25T19:59:00.000+02:00

Tycho Brahe Planetarium

In the planetarium you get introduced to interesting stories about space travel, astronomy and the actual starry sky. Movies, star performances and laser shows are shown at the dome screen. The movies are of the type OMNIMAX - a complex projector. The razor sharp picture is projected at the hemispherically shaped planetarium dome, and a specially designed sound system, constructed by SONICS, surrounds the audience. The result of this is an amazing experience of being in the center of the events as well as being a part of the movie. Tycho Brahe Planetarium also offers many other exciting experiences.
Tycho Brahe Planetarium
Gl. Kongevej 10
1610 København V
Tlf: 33 121224
Internet: www.tycho.dk

Moon Mythology

2006-04-24T21:39:00.000+02:00

According to Harivansha Purana moon was the son of Sage Atri and was nurtured by the ten DISHAS (directions). Moon married the daughters of Daksha Prajapati. They were 27 in number. The names of these daughters are the 27 Nakshatras of the Zodiac. Moon visits each of them for one day in rotation. But he showed Rohini, one of the 27th wives undue favors. He also ran away with the Wife of Brihaspati the Deva Guru. Daksh the father in law cursed Moon to suffer from consumption, a gradual decay. Mercury was born a result of interaction of Moon with the wife of Brihaspati.
According to western concept Moon is considered as Virgin Mary of the Roman Catholics and nourishing mother of the heavens. She is the queen of the night also called Luna (Diana). Diana is the twin sister of Apollo. She governs chastity as well as fertility.

The Science of Space Recycling

2006-04-17T20:33:00.000+02:00

Where does water used on the International Space Station come from? What happens to the water when it's used? How are the station's water and air supplies connected? And what does any of that mean for your classroom?

Image: Expedition 12 Commander Bill McArthur shows a coffee container at the beginning of the video. Credit: NASA

NASA's newest educational resource answers all of those questions, and more. In a six-minute informal video, International Space Station Expedition 12 Commander Bill McArthur explains how other spacecraft bring water to the ISS and how it is used once it gets there. He also tells how water can be recycled or converted into air, using equipment on board the space shuttle and the station. The video is part of a series of educational demonstration activities, in which station crewmembers have discussed life and work in space.

During the educational demonstration activity, station astronauts and cosmonauts talk informally in space about basic principles of science, math, physics, engineering and geography. The crew uses hardware already on board the ISS. The videotaped demonstrations address K-12 audiences, support national standards and enhance existing NASA education products and programs.

Accompanying the recycling video is a free, downloadable supplement. This additional material contains discussion questions and further insights that outline a number of related science, technology, engineering and mathematics, or STEM, concepts. The supplement equips educators with interesting information that is unique to NASA and is provided by its scientists and engineers. The supplement is aligned with national science learning standards and complements STEM lessons for grades 9-12. Educators of other grade levels may find them useful as well.

Image: Fuel cells that provide electrical power for the space shuttle also produce water that is used by space station crews. Credit: NASA

McArthur began his six-month mission on the International Space Station in October 2005, along with Russian flight engineer Valery Tokarev. The crew returned to Earth after handing the station over to the Expedition 13 crew in April 2006. McArthur performed his first educational demonstration activity early in his stay on the ISS. He recorded a lecture about the orbiting laboratory's large solar panels in which he showed how the station's power systems work. He also has demonstrated the importance of safety while working in the Destiny laboratory, shown how supplies are delivered to the station by the Russian Progress vehicle, and compared U.S. and Russian spacesuits. Look for these videos and their accompanying educator insights in the near future at the NASA Web site.

Word From Admin

2006-04-16T18:16:00.000+02:00

Topics below are about planets in our solar system. You can find there some basic information about planets.
From now on I will post interesting (I hope it will be) stories about space and science.

Cheers
~ Aleksa ~

Tags: space, planets, science, solar system, Earth

Mercury

2006-01-16T20:06:00.000+01:00

Mass (kg): 3.3 x 10 23
Diameter (km): 4879.4
Mean density (kg/m 3 ): 5420
Escape velocity (m/s): 4300
Average distance from Sun: 0.387 AU (57,909,175 km)
Rotation period (length of day in Earth days): 58.65
Revolution period (length of year in Earth days): 87.97
Obliquity (tilt of axis degrees): 0
Orbit inclination (degrees): 7
Orbit eccentricity (deviation from circular): 0.206
Mean surface temperature (K): 452 (179 o C)
Maximum surface temperature (K): 700 (427 o C)
Minimum surface temperature (K): 100 (-173 o C)
Satellites: None
Visual geometric albedo: (reflectivity): 0.12
Largest known surface feature: Caloris Basin (1350 km diameter)
Atmospheric components: trace amounts of hydrogen (H) and helium (He)
Surface materials: basaltic and anorthositic rocks and regolith

Venus

2006-01-16T20:04:00.001+01:00

Mass (kg): 4.87 x 10²⁴
Diameter (km): 12104
Mean density (kg/m³): 5250
Escape velocity (m/s): 10400
Average distance from Sun: 0.723 AU (108,208,930 km)
Rotation period (length of day in Earth days): 243.02 (retrograde) Revolution period (length of year in Earth days): 224.7
Obliquity (tilt of axis degrees): 178
Orbit inclination (degrees): 3.39
Orbit eccentricity (deviation from circular): 0.007
Mean surface temperature (K): 726 (453 ^oC)
Satellites: None
Visual geometric albedo: (reflectivity): 0.59
Highest point on surface: Maxwell Montes (17 km above mean planetary radius)
Atmospheric components: 96% carbon dioxide (CO₂), 3% nitrogen (N), 0.1% water vapor (H2O_(g))
Surface materials: basaltic rock and altered materials

Earth

2006-01-16T20:02:00.000+01:00

Mass (kg): 5.98 x 10²⁴
Diameter (km): 12756
Mean density (kg/m³): 5520
Escape velocity (m/s): 11200
Average distance from Sun: 1 AU (149,597,890 km)
Rotation period (length of day in Earth days): 1 (23.93 hours) Revolution period (length of year in Earth days): 365.26
Obliquity (tilt of axis degrees): 23.4
Orbit inclination (degrees): 0
Orbit eccentricity (deviation from circular): 0.017
Mean surface temperature (K): 281 (8 ^oC)
Maximum surface temperature (K): 328 (55 ^oC)
Minimum surface temperature (K): 203 (-70 ^oC)
Satellites: One (Moon)
Visual geometric albedo: (reflectivity): 0.39
Highest point on surface: Mount Everest (over 8 km above sea-level)
Atmospheric components: 78% nitrogen (N), 21% oxygen (O₂), 1% argon (Ar)
Surface materials: basaltic and granitic rock and altered materials

Moon

Diameter (km): 3476
Average distance from Earth: 384,600 km
Maximum surface temperature (K): 378 (105 ^oC)
Minimum surface temperature (K): 118 (-155 ^oC)
Atmospheric components: There aren’t any

Mars

2006-01-16T20:01:00.000+01:00

Mass (kg): 6.42 x 10²³
Diameter (km): 6787
Mean density (kg/m³): 3940
Escape velocity (m/s): 5000
Average distance from Sun: 1.524 AU (227,936,640 km)
Rotation period (length of day in Earth days): 24.6
Revolution period (length of year in Earth days): 686.98
Obliquity (tilt of axis degrees): 25
Orbit inclination (degrees): 1.85
Orbit eccentricity (deviation from circular): 0.093
Maximum surface temperature (K): 310 (37^oC)
Minimum surface temperature (K): 150 (-123 ^oC)
Satellites: Two Visual geometric albedo: (reflectivity) 0.15
Highest point on surface: Olympus Mons (about 24 km above surrounding lava plains)
Atmospheric components: 95% carbon dioxide (CO₂), 3% nitrogen (N), 1.6% argon (Ar)
Surface materials: basaltic rock and altered materials

Jupiter

2006-01-16T19:57:00.000+01:00

Mass (kg): 1.90 x 10²⁷
Diameter(km): 142,800
Mean density(kg/m³): 1314
Escape velocity(m/s): 59500
Average distance from Sun: 5.203 AU (778,412,020 km)
Rotation period(length of day in Earth days): 0.41 (9.8 Earth hours)
Revolution period (length of year in Earth years): 11.86
Obliquity(tilt of axis degrees): 3.08
Orbit inclination (degrees): 1.3
Orbit eccentricity (deviation from circular): 0.048
Mean surface temperature (K): 120 (cloud tops) (-153 ^oC)
Satellites: 62
Visual geometric albedo (reflectivity): 0.44
Atmospheric components: 90% hydrogen (H), 10% helium (He), .07% methane (CH₄)
Rings: Faint ring. Infrared spectra imply dark rock fragments.

Saturn

2006-01-16T19:55:00.000+01:00

Mass (kg): 5.69 x 10²⁶
Diameter (km): 120660
Mean density (kg/m³): 690
Escape velocity (m/s): 35600
Average distance from Sun: 9.537 AU (1,426,725,400 km)
Rotation period (length of day in Earth days): 0.44 (10.2 Earth hours) Revolution period (length of year in Earth years): 29.46
Obliquity (tilt of axis degrees): 26.7
Orbit inclination (degrees:) 2.49
Orbit eccentricity (deviation from circular): 0.056
Mean temperature (K): 88 K (1 bar level) (-185 ^oC)
Satellites: 31
Visual geometric albedo: (reflectivity) 0.46
Atmospheric components: 97% hydrogen (H), 3% helium (He), .05% methane (CH₄)
Rings: Rings are 270,000 km in diameter, but only a few hundred meters thick. Particles are centimeters to decameters in size and are ice (some may be covered with ice); there are traces of silicate and carbon minerals. There are four main ring groups and three more faint, narrow ring groups separated by gaps called divisions.

Uranus

2006-01-16T19:11:00.000+01:00

Mass (kg): 8.68 x 10²⁵
Diameter (km): 51118
Mean density (kg/m³): 1290
Escape velocity (m/s): 21300
Average distance from Sun: 19.19 AU (2,870,972,200 km)
Rotation period (length of day in Earth days): 0.72 (17.9 Earth hours)(retrograde)
Revolution period (length of year in Earth days): 30,685 (84 Earth years)
Obliquity (tilt of axis degrees): 97.9
Orbit inclination (degrees): 0.77
Orbit eccentricity (deviation from circular): 0.047
Mean temperature (K): 59 (-214 ^oC)
Satellites: 27
Visual geometric albedo: (reflectivity) 0.56
Atmospheric components: 83% hydrogen (H), 15% helium (He), 2% methane (at depth) (CH₄)
Rings: Uranus has a system of narrow, faint rings. Rings particles are dark, and could consist of rocky or carbonaceous material.

Neptune

2006-01-16T19:09:00.000+01:00

Mass (kg): 1.02 x 10²⁶
Diameter (km): 49528
Mean density (kg/m³): 1640
Escape velocity (m/s): 23300
Average distance from Sun: 30.07 AU (4,498,252,900 km)
Rotation period (length of day in Earth days): 0.67 (19.1 hours)
Revolution period (length of year in Earth days): 60,190 (164.8 Earth years) Obliquity (tilt of axis degrees): 29.6
Orbit inclination (degrees): 1.77
Orbit eccentricity (deviation from circular): 0.009
Mean temperature (K): 48 (-225 ^oC)
Satellites: 13
Visual geometric albedo: (reflectivity) 0.51
Atmospheric components: 74% hydrogen (H), 25% helium (He), 1% methane (CH₄) (at depth)
Rings: Rings are narrow, and contain concentrations of particles called ring arcs.

Pluto

2006-01-16T19:03:00.000+01:00

Mass (kg): 1.29 x 10²²
Diameter (km): 2300
Mean density (kg/m³): 2030
Escape velocity (m/s): 1100
Average distance from Sun: 39.48 AU (5,906,376,200 km)
Rotation period (length of day in Earth days): 6.39 (retrograde)
Revolution period (length of year in Earth years): 247.92
Obliquity (tilt of axis degrees): 122.5
Orbit inclination (degrees): 17.15
Orbit eccentricity (deviation from circular): 0.248
Mean temperature (K): 37 (-236 ^oC)
Satellites: 1
Visual geometric albedo: (reflectivity) about 0.5
Atmospheric components: perhaps methane (CH₄) and nitrogen (N)
Surface materials: perhaps methane ice

Asteroid

2006-01-16T16:10:00.000+01:00

Definition: Minor planets, small rocky bodies.
Composition: Leftover material from our solar system.
Largest asteroid: 1 Ceres
Total discovered to date: Over 250,000 designations have been assigned by the Minor Planet Center; over 100,000 have been observed more than once.
Total numbered asteroids to date: Over 30,000.
Near-Earth asteroids: Around 1.0 AU from earth, with perihelia less than or equal to 1.3 AU.

Aten group <><><><><> Innermost, semi-major axis less than 1.0 AU, perihelion greater than 0.983 AU.
Apollo group <><><><><> Semi-major axis greater than 1.0 AU, perihelion less than 1.017 AU.
Amor group <><><><><> Semi-major axis greater than 1.0 AU, perihelion between 1.017 and 1.3 AU.

Main Belt Asteroids: Located between orbits of Mars and Jupiter (1.8 to 4.0 AU) in the "asteroid belt".
Trojan Asteroids: Two groups of asteroids located along the orbital path of Jupiter, 60 degrees ahead and behind the planet.
Centaurs: Asteroids in the outer solar system having orbits between Mars and beyond Neptune.
Type Classification: Based on albedo (reflectivity), and color or spectra. Most common are C, S, and M.
C-type: Very dark (albedo=0.03), flat spectra, grayish in color.
S-type: Moderately bright (albedo=0.10-0.22), spectra with moderate to strong absorption bands, greenish to reddish in color.
M-type: Moderately bright (albedo=0.10-0.18), spectra with few absorption bands, reddish in color.

Comets

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Definition: Icy planetesimals formed in the outer solar system.
Composition: Mainly ice and dust
Orbits: Highly elliptical, taking them very close to the Sun and back out into deep space, often far beyond the orbit of Pluto.
Orbit duration: Less than 200 years to more than several millions of years.

*Short-period <><><><><> *Orbits range from a few years (Encke, Chiron) to about 200 years. Referred to as "periodic".
*Long-period <><><><><> *Gravitationally bound, with orbits over 200 years.
*Single-apparition <><><><><> *Parabolic and hyperbolic orbits (not bound).

Periodic comets: Those with short orbit durations
Nucleus: Main body of the comet, composed of dust particles trapped in a mixture of ices of water, carbon monoxide, carbon dioxide, methane, and ammonia. Typically only a few kilometers in diameter.
Coma: A halo of evaporated gas and dust which forms when the comet approaches the inner solar system. The coma grows larger as the comet gets closer to the sun.

Meteorites

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Definition: Meteorites are pieces of solar system debris that have fallen to Earth from space. Prior to reaching Earth's surface, a meteorite is called a "meteor" or "meteoroid.")

Composition: Rock or metal

Size: Most meteorites are tiny, smaller than grains of sand, and vaporize as they pass through the earth's atmosphere. Larger meteorites may be as great as a few miles wide, such as one 65 million years ago that may have wiped out the dinosaurs. The largest intact meteorite found in the USA is the Williamette Meteorite, at 15 and a half tons.

Trans-Neptunian Objects

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Definition: Trans-Neptunian objects (TNOs) are any objects in the solar system that have an orbit beyond Neptune. Pluto is a trans-Neptunian object; another of the named Trans-Neptunian Objects is Varuna.

Total known: There are estimated to be perhaps 70,000 TNOs, each at least 100 km across, between 30 and 50 astronomical units from the Sun.