Let's fuel 2012 doomsday scenarios! How to prevent humanity from a mad asteroid strike.

For a change, let us contemplate about the need of 2012 doomsday defense. No irony intended here, of course.

Article:

To Deflect Killer Asteroids, Humanity Must Work Together

by Mike Wall, SPACE.com Senior Writer
Date: 04 October 2011


An artist's illustration of a large asteroid headed for Earth. CREDIT: ESA

PASADENA, Calif. — The biggest obstacle in deflecting a killer asteroid away from Earth may be humanity's inability to get along.

We already have the technological know-how to prevent dangerous space rocks from barreling into our planet, provided we detect them in time. But this vital job would require a great deal of international cooperation, experts say, and history has shown that working together is not our species' strong suit.
"Somebody's got to make the decision to actually mount the deflection, and do it," said former astronaut Rusty Schweickart, chairman of the B612 Foundation, a group dedicated to predicting and preventing catastrophic asteroid impacts on Earth.

"That is not technical, but it's the toughest problem of all," Schweickart said here at the California Institute of Technology on Sept. 28, during a panel discussion called "Moving an Asteroid." [Photos: Asteroids in Deep Space]

VIDEO: Asteroid Bound - Animated Look at NASA's New Mission


Not if, but when
Our planet has always been pummeled by space rocks. A 6-mile (10-kilometer) asteroid slammed into Earth 65 million years ago, for example, wiping out the dinosaurs.

A potentially civilization-ending asteroid will bear down on Earth at some point, panelists stressed. It's a question of when, not if — and it could happen uncomfortably soon, they said.
Over the eons, asteroids big enough to cause serious damage today (not necessarily the extinction of our species, but disruptions to the global economy and civilizations around the world) have struck Earth every 200 to 300 years, Schweickart said. [5 Reasons to Care About Asteroids]

While the dinosaurs were helpless victims of this death from the sky, 21st-century humans don't have to be.
"What's cool is, we can do something about it," said panelist Bill Nye, executive director of the Planetary Society and former host of the science-themed TV show "Bill Nye the Science Guy."


An artist's impression of a giant space rock slamming into Earth 65 million years ago near what is now Mexico's Yucatan Peninsula. A consortium of scientists now says this was indeed what caused the end of the Age of Dinosaurs. CREDIT: NASA/Donald E. Davis

Giving asteroids a push
Humanity has the technical skills to move asteroids in several different ways, panelists said. We can hurl a large body into them, for example, changing their orbit with one dramatic impact.

NASA did just that in 2005, sending a small probe careening into the comet Tempel 1 to determine the icy wanderer's composition. The goal in that case was science rather than planetary defense, but the key is that humanity knows how to do it with today's technology.

Asteroid deflection could also work in more subtle ways.
Scientists could sidle an unmanned spacecraft up next to a potentially dangerous asteroid, then let the duo cruise through space together for months or years. Over time, the probe's modest gravity would tug the asteroid into a different, more benign orbit, Schweickart said.
This so-called "gravity tractor" technique would allow for precise deflection, making it perhaps the most attractive option, provided we have enough lead time.

Scientists know how to do this, too. Various robotic missions have met up with asteroids over the years, with some even landing on or touching the space rocks. Japan's Hayabusa spacecraft even plucked some pieces off one in 2005, then sent the samples back to Earth for analysis.

If we didn't have very much warning time, and if the threatening space rock was too big to just knock around with an impactor, we could try to blast it apart with a nuclear missile. But this option should only be employed as a last resort, as it may end up doing more harm than good, panelists said.
"Momentum is conserved," Nye said. "If you blow it up, then the whole giant spray of rocks is coming at the Earth instead of one."


A concept spacecraft could use gravity to tow asteroids away from a collision course with earth. CREDIT: Dan Durda - FIAAA / B612 Foundation

Global cooperation needed
A potential asteroid strike would represent a global problem that the world would most likely have to tackle together, Schweickart said.
Cost is one issue that would bring nations together, though likely not the main one. A deflection mission might cost $500 million to $1 billion, Schweickart estimated. So it wouldn't exactly break the bank of the United States or another world power, but fairness would still seem to dictate that the costs be shared.

But many countries would want to be involved to make sure their own voices were being heard, and their own interests were being protected.
Say, for example, that an asteroid appeared to be headed for impact in the north Atlantic Ocean. Russia or China might push for a plan to nudge the asteroid to the west, away from them. The goal, of course, would still be to divert the asteroid away from Earth entirely — but Asia might be spared if the mission moved the asteroid a little, but not enough.

Conversely, the United States and Canada might want to move the asteroid in the other direction. [Natural Disasters: Top 10 U.S. Threats]
"That's why this geopolitical issue is very, very sticky," Schweickart said. "We've got to have agreement between nations."

Starting early
Such agreement might be tough to come by, especially since an effective deflection mission would have to be initiated early to have the best chance of success. We'd need lots of lead time, for example, to launch a gravity tractor spacecraft and give it time to tug on the asteroid.

In fact, we'd have to launch the mission before we were absolutely sure that the space rock in question was actually going to strike Earth, according to Schweickart.
"If you wait until you know, it's too late to act," he said.

Schweickart is pushing hard to raise awareness of the asteroid threat, and to convince people of the need to plan accordingly. He's afraid that the world will have a hard time pulling the trigger on a potentially civilization-saving mission.

"The likelihood is, we're going to end up with a big international debate until the day it hits," Schweickart said. "That's the most likely scenario."

Source:  Space.com

DNA in space? Biological building blocks found in meteorites!

New evidence life on Earth may have come from space objects like meteorites or comets?

Time Article:

SPACE
DNA scraps found in meteorites

By Michael D. Lemonick Thursday - Aug. 11, 2011

Scientists have been finding evidence of life inside meteorites for well over 100 years — that, or the building blocks of life. The claims of life have been debunked every time, most recently just this past March. It always turns out to be a wishful interpretation of chemicals, minerals and tiny structures inside the meteorite that could be the fossilized husks of long-dead bacteria — but almost certainly aren't.


Meteorites contain a large variety of nucleobases, an essential building block of DNA. Credit: Chris Smith / NASA's Goddard Space Flight Center

The building blocks, though, have proved a lot more convincing. As far back as the 1960s, it was clear that amino acids, which link up to form proteins, can and do form in space. And now scientists at NASA's Goddard Space Flight Center in Greenbelt, Md., are claiming that another set of molecules crucial to life have also rained down on Earth: adenine and guanine, two of the four so-called nucleobases that, along with cytosine and thymine, form the rungs of DNA's ladder-like structure. (See pictures of meteors that fell from the sky.)

By itself, that wouldn't mean much, says Michael Callahan, lead author of a new paper in Proceedings of the National Academy of Sciences. "People have been finding nucleobases in meteorites since the late 1960s," he says. But they've always been among the handful of nucleobases common to organisms on Earth, so contamination on the ground after the meteorite landed has been the most likely explanation. "When I picked up on this research," says Callahan, a chemist with Goddard's Astrobiology Analytical Laboratory, "I was convinced that it was all contamination."

But once he and his collaborators got hold of samples from 12 meteorites that had landed mostly in Antarctica and ran them through the lab's liquid chromatograph and mass spectrometer, they discovered all sorts of other molecules — substances that were similar in structure but not biologically useful. That was a surprise; if a meteorite picked up its biological traces on the ground, the adenine and guanine would have been accompanied by other, equally familiar molecules — not these substances that were not quite nucleobases but not quite not either. (See TIME's photo-essay "The Hubble Telescope's Greatest Hits.")

"That," says Callahan, "argues against the idea that someone sneezed on the meteorites." Another argument against earthly contamination is that when the scientists took samples of ice and soil from the sites where the meteorites were found, they saw the usual terrestrial mix of organic molecules but not their nonbiological cousins. If the molecules came from the landing sites rather than from space, you'd expect to see the nonbiological cousins as well.

A third line of evidence comes from the fact that life-related substances are common in space. Hydrogen cyanide, ammonia and water — critical to building biology — are known to exist throughout the cosmos, and when you mix them together in a lab, says Callahan, "it's pretty easy to make nucleobases." It's not even a little bit of a stretch to imagine that the same processes could happen on, or in, a meteorite. It's also at least plausible that life would never have arisen on our planet without a liberal dose of space chemicals, delivered to Earth on a barrage of meteorites billions of years ago. (See "Space Discovery: Asteroids May Have Served as Incubators of Life.")

The new research doesn't address the question of panspermia, the not entirely crazy idea that life arrived on our planet fully formed as viruses or bacteria that developed on another world. If that turns out to be the case — if we find microbes on Mars or on a meteorite, for example, with DNA identical to ours — we might face the disturbing fact that we're the contamination on a formerly pristine planet.

What the new research does is reinforce an idea that astronomers and biologists — and, increasingly, the people who call themselves astrobiologists — find very convincing: since the raw materials of life are common in the universe, and since we now know that planets are common as well, it's hard to imagine how the Milky Way could not be teeming with life. Our species may continue to be special in a lot of ways — but perhaps a little less so than we thought.


Source: TIME health magazine

Perseids meteor shower - great time to gaze into space!

The night of Friday, August 12 into the early morning of Saturday, August 13 will certainly be the best time of the year to watch meteor showers. Everyone, get your telescopes out of the garret!

Article:

Stay 'Up All Night' to Watch the Perseids!

08.12.11 - NASA Marshall Space Flight Center, Huntsville, Alabama

Looking for a good reason to enjoy an August evening? This year's Perseid meteor shower peaks on the night of Friday, Aug. 12 and into the early morning of Saturday, Aug 13. The Perseids are considered the best meteor shower of the year by many, but with the full moon washing out all but the brightest meteors, rates will probably only be 20-30 per hour at most -- weather permitting. The Perseids rate in the southern hemisphere is quite a bit lower, since the Perseid radiant doesn't climb above the horizon.


Perseid meteor shower. Image credit: NASA / Michael Menefee. Full resolution.

Watch the Perseids! Live Video/Audio Feed

A live video/audio feed of the Perseid shower will be embedded below on the night of the chat. The camera is mounted at NASA's Marshall Space Flight Center in Huntsville, Ala. During the day, you'll see a dark gray box -- the camera is light-activated and will turn on at dusk each evening. At night you'll see white points, or stars, on a black background. You can also access these links to more all sky cameras to have other views of the sky.

Before the camera activates, you can still hear the audio of meteors passing through the sky, creating blips, pings and whistles. The meteors themselves don't make sounds, but they ionize the air around them as they burn up. These ionized air molecules reflect radio waves back to our antenna.

More About the Perseids

The Perseids have been observed for at least 2,000 years and are associated with the comet Swift-Tuttle, which orbits the sun once every 133 years. Each year in August, the Earth passes through a cloud of the comet's debris. These bits of ice and dust -- most over 1,000 years old -- burn up in the Earth's atmosphere. The Perseids can be seen all over the sky, but the best viewing opportunities will be across the northern hemisphere. Those with sharp eyes will see that the meteors appear to radiate from the direction of the constellation Perseus.


Source: nasa.gov