The Big Space Exploration Thread

[VelesHomais]

PASADENA, Calif. -- By precisely tracking NASA's Cassini spacecraft on its low swoops over Saturn's moon Titan, scientists have determined the distribution of materials in the moon's interior. The subtle gravitational tugs they measured suggest the interior has been too cold and sluggish to split completely into separate layers of ice and rock.




The finding, to be published in the March 12 issue of the journal Science, shows how Titan evolved in a different fashion from inner planets such as Earth, or icy moons such as Jupiter's Ganymede, whose interiors have split into distinctive layers.

"These results are fundamental to understanding the history of moons of the outer solar system," said Cassini Project Scientist Bob Pappalardo, commenting on his colleagues' research. Pappalardo is with NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We can now better understand Titan's place among the range of icy satellites in our solar system."

Scientists have known that Titan, Saturn's largest moon, is about half ice and half rock, but they needed the gravity data to figure out how the materials were distributed. It turns out Titan's interior is a sorbet of ice studded with rocks that probably never heated up beyond a relatively lukewarm temperature. Only in the outermost 500 kilometers (300 miles) is Titan's ice devoid of any rock, while ice and rock are mixed to various extents at greater depth.

"To avoid separating the ice and the rock, you must avoid heating the ice too much," said David J. Stevenson, one of the paper's co-authors and a professor of planetary science at the California Institute of Technology in Pasadena. "This means that Titan was built rather slowly for a moon, in perhaps around a million years or so, back soon after the formation of the solar system."

This incomplete separation of ice and rock makes Titan less like Jupiter's moon Ganymede, where ice and rock have fully separated, and perhaps more like another Jovian moon, Callisto, which is believed to have a mixed ice and rock interior. Though the moons are all about the same size, they clearly have diverse histories.

The Cassini measurements help construct a gravity map, which may help explain why Titan has a stunted topography, since interior ice must be warm enough to flow slowly in response to the weight of heavy geologic structures, such as mountains.

Creating the gravity map required tracking minute changes in Cassini's speed along a line of sight from Earth to the spacecraft as it flew four close flybys of Titan between February 2006 and July 2008. The spacecraft took paths between about 1,300 to 1,900 kilometers (800 to 1,200 miles) above Titan.

"The ripples of Titan's gravity gently push and pull Cassini along its orbit as it passes by the moon and all these changes were accurately recorded by the ground antennas of the Deep Space Network within 5 thousandths of a millimeter per second [0.2 thousandths of an inch per second] even as the spacecraft was over a billion kilometers [more than 600 million miles] away," said Luciano Iess, a Cassini radio science team member at Sapienza University of Rome in Italy, and the paper's lead author. "It was a tricky experiment."

The results don't speak to whether Titan has an ocean beneath the surface, but scientists say this hypothesis is very plausible and they intend to keep investigating. Detecting tides induced by Saturn, a goal of the radio science team, would provide the clearest evidence for such a hidden water layer.

A Cassini interdisciplinary investigator, Jonathan Lunine, said of his colleagues' findings, "Additional flybys may tell us whether the crust is thick or thin today." Lunine is with the University of Rome, Tor Vergata, Italy, and the University of Arizona, Tucson. "With that information we may have a better understanding of how methane, the ephemeral working fluid of Titan's rivers, lakes and clouds, has been resupplied over geologic time. Like the history of water on Earth, this is fundamental to a deep picture of the nature of Titan through time."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of Caltech, manages the project for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL. Cassini's radio science subsystem has been jointly developed by NASA and the Italian Space Agency (ASI).

More Cassini information is available, at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

[Trelawny]

Originally Posted by VelesHomais

Top 5 Bets for Extraterrestrial Life in the Solar System





1. Enceladus
The sixth-largest moon of Saturn has been called the most promising bet for life thanks to its welcoming temperature and the likely presence of water and simple organic molecules. The surface of the icy moon is thought to be about 99 percent water ice, with a good chance of liquid water beneath. Observations from the Cassini probe’s 2005 flyby of Enceladus suggest the presence of carbon, hydrogen, nitrogen and oxygen — organic molecules thought to be necessary to develop life. And the moon seems to have a boiling core of molten rock that could heat the world to the toasty temperatures needed to give rise to life.



2. Europa
Jupiter’s moon Europa also seems a possible stomping ground for E.T. due to its potential water and volcanic activity. Though the surface seems to be frozen, many suspect that buried underneath is an ocean of liquid water. Volcanic activity on the moon could provide life-supporting heat, as well as important chemicals needed by living organisms. Microbial life could potentially survive near hydrothermal vents on Europa, as it does on Earth.



3. Mars
As far as planets go, by far the front-runner for life is our next-door neighbor, Mars. The red planet is the most Earth-like of solar system planets, with a comparatively similar size and temperature range as our own planet. Large bodies of water ice lie on Mars’ poles, and there’s a reasonable chance of liquid water beneath the surface. The puny atmosphere on the planet is not strong enough to shield the planet against lethal solar radiation, though microbes could potentially exist beneath the surface. Evidence also suggests that Mars may have been even more habitable in the past. Geologic features imply that liquid water once flowed across the surface, and volcanic activity, now dead, once flourished, recycling chemicals and minerals between the surface and the interior.



4. Titan
Saturn’s largest moon looks suspiciously like it might have hosted life, because its thick atmosphere is rich in compounds that often mark the presence of living organisms. For instance, Titan’s air is filled with methane, which is usually destroyed by sunlight. On Earth, life constantly replenishes methane, so it might similarly be responsible for the methane on Titan. Titan is rather cold, however, and if liquid water exists, it must be deep beneath the frozen surface. P.S. but it does have liquid surface rivers and huge lakes made up of liquid methane.



5. Io
Jupiter’s moon Io is one of the few solar system moons to support an atmosphere, and it contains complex chemicals promising for life. Volcanism on the moon also makes it warmer than many others — another good sign. Io is still a long shot, though, because its location inside Jupiter’s magnetic field means it is constantly being pelted with lethal radiation. Its violent surface also seems inhospitable, with temperatures often too cold to support life, as well as molten hot spots that are equally deadly.

http://www.wired.com/wiredscience/2009/01/et-life/

Cool!! I never heard of Enceladus before. They just need to explore Mars to see if there is any life, we can't just keep looking through microscopes we have to go up.

[VelesHomais]

Just imagine that there are some intelligent fish living there, but even if it's a couple of microbes, it will be a life altering discovery for all of us.

[VelesHomais]

First Commercial Spaceship Flight: 2014 ?



VSS ENTERPRISE will be mankind's first commercial spaceship, delivering tourists into Earth's suborbit on a regular basis. While no scientific or technological achievement by any standards, it will open up a realistic possibility for any wealthy human to travel into space and take a look at Earth, if only for six minutes. If financially successful, New Mexico, USA based company funded by an eccentric British entrepreneur, intends to offer space flights around the Moon.

image hosted on flickr

[ch1le]

Originally Posted by VelesHomais

One Year Before First Commercial Spaceship Flight



VSS ENTERPRISE will be mankind's first commercial spaceship, delivering tourists into Earth's lower orbit on a regular basis. While no scientific or technological achievement by any standards, it will open up a realistic possibility for any wealthy human to travel into space and take a look at Earth, if only for six minutes. If financially successful, New Mexico, USA based company funded by an eccentric British entrepreneur, intends to offer space flights around the Moon.

image hosted on flickr

it wont reach orbit. Its suborbital.

[Oaronuviss]

Originally Posted by VelesHomais

Phoenix revolutionized our understanding of Martian weather, found frozen water, recorded snowfall and a lot more. These findings will be crucial for when humans begin to colonize Mars before its terraformation.

That's a bold statement! As awesome as that would be, it would take billions of years to terraform Mars. Starting now.

[desertpunk]

Virgin Galactic flights got pushed back to 2014. Testing will begin in 2012

And yes, right here in New Mexico:









All facilities are currently under construction.

[wjfox]

Originally Posted by Oaronuviss

it would take billions of years to terraform Mars.

Why would it take billions of years? With a network of giant solar mirrors focussing heat onto the poles, along with self-replicating nanobots on the ground, it could be accomplished in a few centuries. Positive feedback loops would accelerate much of the warming.

The only really difficult part would be creating an artificial magnetosphere. This could take the form of metallic rings running around the latitude lines, placed underground. It would be a megaproject even by 23rd-24th century standards, but it could be done with the help of robots.

[VelesHomais]

Originally Posted by Oaronuviss

That's a bold statement! As awesome as that would be, it would take billions of years to terraform Mars. Starting now.

No, it will take about 200 years and will probably start on NASA/U.S. government level by 2090-2110. Besides, it's a gradual process, first visible results will be seen as soon as 2200. Besides, colonization of Mars is going to start within your lifetime, even without any plans of terraformation.

[Trelawny]

Wouldn't cooling down Venus be easier than warming up Mars? Venus just needs to loosen up their atmosphere then they are good.

[VelesHomais]

I don't know, but we can't live on Venus before Terraformation, but we can live on Mars even with existing technology, it's just a matter of money. In one hundred years there will be plenty of scientists living on Mars.

[VelesHomais]

Originally Posted by ch1le

it wont reach orbit. Its suborbital.

Fixed. But next time don't quote the whole thing, it's annoying.

[Trelawny]

Originally Posted by VelesHomais

I don't know, but we can't live on Venus before Terraformation, but we can live on Mars even with existing technology, it's just a matter of money. In one hundred years there will be plenty of scientists living on Mars.

Lol you know how many protests there will be from environment people all across the Earth? We messes up the Earth now we want to go to Mars to look for Helium or something.

[VelesHomais]

Those protesting terraformation of Mars will be lunatics. Mankind is destined to live on Mars. Besides, in a hundred years we'll have technology that will ensure sustainable way of life that doesn't interfere with progress.

I watched a program on the Science Channel where a astrophysicists declared that Earth will be hit with a devastating meteorite, it's just a matter of time, because there are so many gigantic rocks flying in space. Populating another planet will ensure humanity's survival.

P.S. I just checked, there already are people against populating Mars

[Trelawny]

I don't know if man was destined to live on earth. If you are religious you might think the creator put us on this planet for a reason and he made life on other planets near impossible so we wouldn't leave. And i know there is a meteorite that could possibly hit the earth near the end of this millennium. However being that the first Nuke was created in the 20th century i am sure by the 30th century meteorites shouldn't be a problem.

[desertpunk]

Originally Posted by Trelawny

I don't know if man was destined to live on earth. If you are religious you might think the creator put us on this planet for a reason and he made life on other planets near impossible so we wouldn't leave. And i know there is a meteorite that could possibly hit the earth near the end of this millennium. However being that the first Nuke was created in the 20th century i am sure by the 30th century meteorites shouldn't be a problem.

We can easily reach distant earth-like planets. All it requires is some auspicious reincarnation.

[Trelawny]

Originally Posted by desertpunk

We can easily reach distant earth-like planets. All it requires is some auspicious reincarnation.

You think we will colonize the galaxy? Whats the point in that?

[Qatar Son 333]

In the really far future, around 1,000,000,000,000,000,000 AD

[Fallout]

Originally Posted by Trelawny

You think we will colonize the galaxy? Whats the point in that?

Perhaps it will be easier to fly for 20 years to extrasolar planet in suspended animation than to terraform Mars?

[Iluminat]

Perhaps humans in the future wouldn't need "terraformation" as much as we would