Space and Astronomy Megathread (MERGED)

Is it real?

  • Yes

  • No, it's a hoax

  • It's something else

  • Yes

  • No, it's a hoax

  • It's something else

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Thats awesome. thats happening with us (milky way galaxy) and the Andromeda Galaxy.
 
Mars is coming!

You've probably heard that line before – no doubt fairly recently, thanks to a bogus e-mail that unfortunately received wide circulation on the Internet this summer with promises of Mars being as big as the full moon.

But this fact is absolutely true: Mars, the only planet whose surface we can see in any detail from the Earth, is now moving toward the best viewing position it will provide to us until the year 2014. Planet watchers have already begun readying their telescopes.

If you haven't seen it, it will be well worth looking for the red planet next week, even though you'll have to wait until after midnight to see it well.

Mars is currently midway between the zodiacal constellations of Taurus, the Bull and Gemini, the Twins and during this week it will rise shortly before 11 p.m. local daylight time. There is certainly no mistaking it once it comes up over the east-northeast horizon. Presently shining like a pumpkin-hued, zero magnitude star, Mars is currently tied for fifth place (with Vega) among the 21 brightest stars.

But as it continues to approach our Earth in the coming weeks and months, Mars will only be getting brighter: it will surpass Sirius, the brightest star in the sky by Dec. 9 and during the latter half of December it will even almost match Jupiter in brilliance.

Late next Wednesday night (or more precisely, early on Thursday morning), Mars will hover about 7-degrees above and to the right of the last quarter moon as they rise above the east-northeast horizon (your clenched fist held at arm's length is roughly 10-degrees in width). As you will see for yourself, the so-called "Red Planet" actually will appear closer to a yellow-orange tint – the same color of a dry desert under a high sun.

How close?

Every 26 months, or so, Earth makes a close approach to Mars, as our smaller, swifter orbit "overtakes" Mars around the sun. Because both the orbits of Mars and Earth are mildly elliptical, some close approaches between the two planets are closer than others.

This current apparition of Mars will be nowhere near as spectacular as the oft-referred approach of August 2003 when the planet came closer to Earth than it had in nearly 60,000-years.

Rather, on this upcoming occasion, Mars will come closest to Earth on the evening of December 18th (at around 6:46 p.m. Eastern Standard Time).

The planet will then lie 54.8 million miles (88.2 million kilometers) from Earth as measured from center to center. Mars will arrive at opposition to the sun (rising at sunset, setting at sunrise) six days later on Christmas Eve, December 24th.
How big?

That recent Martian e-mail message – a hyperbole which was widely circulated for a fourth consecutive year – lead people to believe, with liberal use of exclamation marks, that on Aug. 27, Mars would appear as bright as (or as large as) that night's full moon in the night sky. The subject header urged viewers to prepare to view "Two Full Moons."

It was amazing (and a little disturbing) to see just how many people actually believed that Mars could loom so large in our sky. But the truth is that even when at its absolute closest possible approach to Earth, Mars can appear no larger than 1/72 as big as the moon; to the unaided eye it would appear as nothing more than an extremely bright, non-twinkling star.

When it comes closest to Earth on December 18th of this year, Mars' apparent disk diameter will be equal to 15.9 arc seconds. To get an idea of just how large this is, wait until darkness falls this week and if you have a telescope, check out Jupiter, gleaming in the southwestern sky; it'll appear about 35 arc seconds across.

In contrast, Mars' disk will appear less than half as big as Jupiter's when the Red Planet comes closest to Earth later this year. While this may sound small, keep in mind that this is still atypically large for Mars. In fact, from November 30th through Jan. 5, 2008, Mars' apparent size will be larger than at any time until April 2014. Around the time that Mars is closest, amateurs with telescopes as small as 4-inches and magnifying above 120-power should be able to make out some dusky markings on the small yellow-orange disk, and perhaps the bright white polar cap.

Size isn't everything

From Dec. 15 through Dec. 29, Mars will blaze at magnitude -1.6, a bit brighter than Sirius, but just slightly inferior to Jupiter. Mars will still be positioned between Taurus and Gemini, at a rather high declination of about +27-degrees.

So almost as if to compensate for its relatively small apparent size, Mars will literally soar in the night sky of late-December.

When it reaches its highest point in the sky at around midnight local time, its altitude will be 70-degrees at Seattle, 76-degrees for New York, and an exceptional 83-degrees at Los Angeles. Meanwhile, amateur and professional astronomers stationed in southern Texas and central Florida will see Mars pass directly, or very nearly overhead!
 
Ice-man said:
Mars is coming!

You've probably heard that line before – no doubt fairly recently, thanks to a bogus e-mail that unfortunately received wide circulation on the Internet this summer with promises of Mars being as big as the full moon.

But this fact is absolutely true: Mars, the only planet whose surface we can see in any detail from the Earth, is now moving toward the best viewing position it will provide to us until the year 2014. Planet watchers have already begun readying their telescopes.

If you haven't seen it, it will be well worth looking for the red planet next week, even though you'll have to wait until after midnight to see it well.

Mars is currently midway between the zodiacal constellations of Taurus, the Bull and Gemini, the Twins and during this week it will rise shortly before 11 p.m. local daylight time. There is certainly no mistaking it once it comes up over the east-northeast horizon. Presently shining like a pumpkin-hued, zero magnitude star, Mars is currently tied for fifth place (with Vega) among the 21 brightest stars.

But as it continues to approach our Earth in the coming weeks and months, Mars will only be getting brighter: it will surpass Sirius, the brightest star in the sky by Dec. 9 and during the latter half of December it will even almost match Jupiter in brilliance.

Late next Wednesday night (or more precisely, early on Thursday morning), Mars will hover about 7-degrees above and to the right of the last quarter moon as they rise above the east-northeast horizon (your clenched fist held at arm's length is roughly 10-degrees in width). As you will see for yourself, the so-called "Red Planet" actually will appear closer to a yellow-orange tint – the same color of a dry desert under a high sun.

How close?

Every 26 months, or so, Earth makes a close approach to Mars, as our smaller, swifter orbit "overtakes" Mars around the sun. Because both the orbits of Mars and Earth are mildly elliptical, some close approaches between the two planets are closer than others.

This current apparition of Mars will be nowhere near as spectacular as the oft-referred approach of August 2003 when the planet came closer to Earth than it had in nearly 60,000-years.

Rather, on this upcoming occasion, Mars will come closest to Earth on the evening of December 18th (at around 6:46 p.m. Eastern Standard Time).

The planet will then lie 54.8 million miles (88.2 million kilometers) from Earth as measured from center to center. Mars will arrive at opposition to the sun (rising at sunset, setting at sunrise) six days later on Christmas Eve, December 24th.
How big?

That recent Martian e-mail message – a hyperbole which was widely circulated for a fourth consecutive year – lead people to believe, with liberal use of exclamation marks, that on Aug. 27, Mars would appear as bright as (or as large as) that night's full moon in the night sky. The subject header urged viewers to prepare to view "Two Full Moons."

It was amazing (and a little disturbing) to see just how many people actually believed that Mars could loom so large in our sky. But the truth is that even when at its absolute closest possible approach to Earth, Mars can appear no larger than 1/72 as big as the moon; to the unaided eye it would appear as nothing more than an extremely bright, non-twinkling star.

When it comes closest to Earth on December 18th of this year, Mars' apparent disk diameter will be equal to 15.9 arc seconds. To get an idea of just how large this is, wait until darkness falls this week and if you have a telescope, check out Jupiter, gleaming in the southwestern sky; it'll appear about 35 arc seconds across.

In contrast, Mars' disk will appear less than half as big as Jupiter's when the Red Planet comes closest to Earth later this year. While this may sound small, keep in mind that this is still atypically large for Mars. In fact, from November 30th through Jan. 5, 2008, Mars' apparent size will be larger than at any time until April 2014. Around the time that Mars is closest, amateurs with telescopes as small as 4-inches and magnifying above 120-power should be able to make out some dusky markings on the small yellow-orange disk, and perhaps the bright white polar cap.

Size isn't everything

From Dec. 15 through Dec. 29, Mars will blaze at magnitude -1.6, a bit brighter than Sirius, but just slightly inferior to Jupiter. Mars will still be positioned between Taurus and Gemini, at a rather high declination of about +27-degrees.

So almost as if to compensate for its relatively small apparent size, Mars will literally soar in the night sky of late-December.

When it reaches its highest point in the sky at around midnight local time, its altitude will be 70-degrees at Seattle, 76-degrees for New York, and an exceptional 83-degrees at Los Angeles. Meanwhile, amateur and professional astronomers stationed in southern Texas and central Florida will see Mars pass directly, or very nearly overhead!
Click to expand...

soo...im confused. just how big will it be in the sky? someone draw a picture.
 
Since you guys merged all the space threads, why didn't you merge the one with the planet with the exotic water and ice in July? :huh: And why are all my post in this thread gone? *sigh* black man just can't get a break! :(
 
I still remember the thread with the largest star ever seen by humans.It was the size of the solar system.
 
Docker said:
what!??! where's this thread? :huh:
Click to expand...

It was just a scale in a pictorial representation... supermassive star can extend from our sun to between the orbits of Jupiter and even Saturn.
 
Solving A Solar System Quandary By Flip-Flopping Uranus And Neptune


by Staff Writers
Tempe AZ (SPX) Dec 13, 2007
Quick: What's the order of the planets in the solar system? Need a little help? Maybe the following mnemonic rings a bell: "My Very Educated Mother Just Served Up Nine Pizzas." It's useful for remembering the order of the planets today, but it wouldn't have been as useful in the past, and not just because the International Astronomical Union demoted Pluto to "dwarf planet" last year.
The reason this mnemonic wouldn't have worked is because the planets weren't always in the order they are today. Four billion years ago, early in the solar system's evolution, Uranus and Neptune switched places.

This is the result of recent work by Steve Desch, assistant professor in the School of Earth and Space Exploration at Arizona State University. The work appears in this week's Astrophysical Journal. Desch based his conclusion on his calculations of the surface density of the solar nebula.

The solar nebula is the disk of gas and dust out of which all of the planets formed. The surface density - or mass per area - of the solar nebula protoplanetary disk is a fundamental quantity needed to calculate everything from how fast planets grow to the types of chemicals they are likely to contain.

It's very hard to observe the surface density in protoplanetary disks forming solar systems today, both because they're too far away and because most observations detect only dust and miss everything larger than a baseball. So for the last 30 years most researchers have relied on an estimate of the surface density called the Minimum Mass Solar Nebula.

The idea is simple: take the rocky component of each planet, add hydrogen and helium until it matches the Sun in composition, and spread the mass over the area of each planet's orbit. The minimum mass solar nebula predicts disk masses not too different from what we can observe in forming solar systems. But it also predicts low surface densities, with the mass too spread out to form planets quickly.

"I was thinking about planet formation and noticing that all the current models failed to predict how Jupiter could grow to its current size in the life time of the solar nebula," Desch recounts. "Given Jupiter's composition and size, models predicted it would take many millions of years for it to form, and billions of years for Uranus and Neptune - but our solar system isn't that old," says Desch. "That's when I ran across the Nice model."

The Nice model (named for the city in France where it was developed) is based on sophisticated numerical calculations of the planets' orbits over millions of years.

It explains several aspects about the orbits of Jupiter, Saturn, Uranus and Neptune, as well as the Kuiper Belt of comets beyond, by assuming the giant planets formed a lot closer together than they're found today. Neptune, for example, formed less than half the distance from the Sun that it orbits today. And in 50% of their simulations, Uranus and Neptune switched places, although there was no way to determine whether they did or not.

Desch realized the Nice model implied the mass of the solar system was packed together more tightly than the minimum mass solar nebula assumed. By spreading the masses of the planets over their original orbits, as predicted by the Nice model, he found a very smooth variation of surface density with distance from the Sun, albeit one that fell off very sharply far from the Sun.

The fit varied by only a few percent from the planets' masses, but only if Uranus and Neptune did indeed switch places. "Neptune had to form closer to the sun than Uranus or you don't get the smooth profile," says Desch.

The new findings have other profound implications. "The surface density of the solar nebula isn't what we originally thought - it is actually much higher - and this has implications for where we formed and for how fast planets grow.

A higher surface density of the solar nebula means that Uranus and Neptune formed closer and faster, in only 10 million years instead of billions," says Desch. That's important because Uranus and Neptune contain a few Earth masses of hydrogen and helium gas, and observations of other protoplanetary disks show these gases don't hang around for more than 10 million years.

In addition to demonstrating for the first time that all of the giant planets can grow within the lifetime of the solar nebula, Desch also uncovered the reason behind the sharp variation in density with distance from the Sun. "The distribution of mass falls off very steeply because the outer edge is constantly being boiled away through the process of photoevaporation, by the ultraviolet radiation of nearby massive stars."

Prior to this, researchers had not considered the effects of photoevaporation on the mass distribution of the solar system. Desch's work shows that photoevaporation does move mass from the outer edge but at a fixed rate so it keeps it from spreading out too much, thus aiding planet growth.

So it seems that 4 billion years ago, "My Very Educated Mother Just Served Nine Up Pizzas" would have been the mnemonic to learn. Says Desch, "This reminds us that the solar system is a dynamic place. For the first 650 million years of the solar system Neptune was closer to the sun than Uranus - that's 15% of the history of the solar system. It looked completely different than we see it today."
 
Galaxy Blasts Neighbor with Deadly Jet
By Dave Mosher, Staff Writer

posted: 17 December 2007 01:26 pm ET

This story was updated at 1:42 p.m. ET.

For the first time astronomers have witnessed a supermassive black hole blasting its galactic neighbor with a deadly beam of energy.

The "death star galaxy," as NASA astronomers called it, could obliterate the atmospheres of planets but also trigger the birth of stars in the wake of its destructive beam. Fortunately, the cosmic violence is a safe distance from our own neck of the cosmos.

"We've seen many jets produced by black holes, but this is the first time we've seen one punch into another galaxy like we're seeing here," said Dan Evans, astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "This jet could be causing all sorts of problems for the smaller galaxy it is pummeling."

Evans and his colleagues detail their findings in an upcoming issue of the Astrophysical Journal.

Cosmic death

The deadly galaxy — the largest of two in a system known as 3C321 — is aiming the high-energy jet from its center at a smaller galaxy 20,000 light-years away from it, or roughly the distance from Earth to the Milky Way's core. Both galaxies are situated about 1.4 billion light-years away from Earth.

A bright spot in a NASA composite image reveals that the beam is striking the edge of the smaller galaxy, deflecting the spindle of energy into intergalactic space. While not a direct hit, astronomers said the consequences are frightening.

"This is a fascinating result, and we can be glad that we're seeing it from a safe distance," said Neil deGrasse Tyson, an astrophysicist at the American Museum of Natural History in New York who did not contribute to the study. "Knowing how lethal the radiation from the jet could be, I wouldn't want to be anywhere near its line of fire."

Jets from supermassive black holes produce tremendous radiation in the form of X-rays, gamma rays and electrons traveling close to the speed of light. Evans said, however, that the X-ray and gamma-ray photons would ultimately do the most damage to planets.

"The photons can have a really dramatic, profound effect on a planetary atmosphere," he said. "It's likely the ozone layer on an Earth-like planet would be destroyed within months."

Without an ozone layer to protect a planet from deadly space radiation, Tyson said creatures on a planet's surface would perish quickly.

"You would basically render extinct all surface forms of life," Tyson said. "But it may be that subterranean life is ... immune to this kind of violence in the universe."

Recent attack

The offending galaxy probably began assaulting its companion about 1 million years ago, which is relatively recent on a cosmic time scale. Evans said the unusual event makes 3C321 an important object for learning more about the universe.

"We've seen jets do pretty weird things to their environments, but a head-on collision is really rare and generates a [large] amount of information about physics that we can understand and use," Evans said. "For that galaxy to be looking right down ... the barrel of the gun of that jet is incredibly rare, so this makes it a really exciting discovery."

Turns out that the "death ray" may not be all bad news for the victimized galaxy, at least theoretically, as such a massive influx of energy and radiation could help form new stars and solar systems by compressing gases.

"In the end [3C321] may be the source of new life in that distant galaxy," said Martin Hardcastle, an astronomer at the University of Hertfordshire, in the United Kingdom. Hardcastle explained that the jet will continue to pour out of its parent supermassive black hole for about 10 to 100 million longer — plenty of time to squeeze otherwise inert gas together into new star systems.

"Jets can be highly disruptive ... but [create] stellar nurseries," Tyson said. "It's a fascinating sort of duality about how these high-energy phenomena influence the environments in which they're embedded."

To fully view the galactic violence and rebirth, astronomers used NASA's Chandra X-ray observatory, Hubble and Spitzer space telescopes, and the Very Large Array and MERLIN radio telescopes on Earth.

http://www.livescience.com/space/scienceastronomy/071217-death-star-galaxy.html
 
found it

silicasoil_spirit_big.jpg


On the Planet Mars Silica has been found. Its the first time silica has been discoverd on the Planet Mars. silica is what forums Glass and Quartz.


You're rolling across Mars when you unexpectedly uncover some unusually light soil. You stop. You turn. You return to inspect the soil and find out it is almost purely silica -- the main ingredient in quartz and glass. Such soil has never been found on Mars before. What created this soil? Since you are the robotic rover Spirit currently rolling across Mars, you send the images and data back to Earth for analysis. Your scientist friends from the blue water planet say that such soil on Earth is usually created by either volcanic steam or a hot spring. The second hypothesis in particular indicates, once again, a wet past for part of Mars, as possibly hot water saturated with silica deposited the white soil. Intriguingly, on Earth, living microbes typically flourish under either condition. Pictured above, the uncovered light soil is visible on the right.
 
Europa, a moon of Jupiter

europa_galileo_big.jpg


Although the phase of this moon might appear familiar, the moon itself might not. In fact, this gibbous phase shows part of Jupiter's moon Europa. The robot spacecraft Galileo captured this image mosaic during its mission orbiting Jupiter from 1995 - 2003. Visible are plains of bright ice, cracks that run to the horizon, and dark patches that likely contain both ice and dirt. Raised terrain is particularly apparent near the terminator, where it casts shadows. Europa is nearly the same size as Earth's Moon, but much smoother, showing few highlands or large impact craters. Evidence and images from the Galileo spacecraft, indicated that liquid oceans might exist below the icy surface. To test speculation that these seas hold life, ESA has started preliminary development of the Jovian Europa Orbiter, a spacecraft proposed to orbit Europa. If the surface ice is thin enough, a future mission might drop hydrobots to burrow into the oceans and search for life.

http://antwrp.gsfc.nasa.gov/apod/ap071202.html
 
NASA's Image of the Day!

baadewindow_guisard_big.jpg


Billions of stars light up the direction toward the center of our Galaxy. The vast majority of these stars are themselves billions of years old, rivaling their home Milky Way Galaxy in age. Together with interstellar dust, these old stars combine to create this yellowish starscape. Although the opaque dust obscures the true Galactic center in visible light, there is a low density hole in the dust on the right of the image. The region, named Baade's Window for the German astronomer who studied it, is used to inspect distant stars and to determine the internal geometry of the Milky Way. Baade's Window lies toward the constellation of the Archer (Sagittarius).
 
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