Saturday, April 28, 2012

Astronomers Worried Enough To Urge World To Prepare For Asteroids To Hit Earth.

Astronomer urges world to prepare for asteroids to hit earth
By John Hollenhorst
SALT LAKE CITY — Threats from the skies are real, and they could could push the human race to extinction, according to a prominent astronomer who spoke Friday in Logan. But he's quick to denounce a popular "end of the world" notion making the rounds this year.
The fearful — or playful — fad now is the supposed 2012 doomsday prophecy of the Mayan calendar. A prominent astronomer says it's all nonsense. But even he is raising the alarm about "death from the skies."
Hollywood loves a good catastrophe. What better use of special effects than threats from the sky … or deep in the Earth?
And astronomer-blogger Phil Plait enjoys talking about the scary, but improbable events that could snuff us out in a twinkling of the cosmic eye. He wrote a book on all the ways the human race could come to an end.
"Astroid impacts, big solar storm, nearby supernova, there's a super-violent event called a gamma-ray burst. And this can wipe out life across the galaxy," he said.
He's visiting Utah State's College of Science to deliver a message that is slightly unsettling.
"Space is fairly dangerous," he said. "I like to say that the universe is trying to kill us."
This is a guy who puts no stock in the Mayan Calendar 2012 end of the world frenzy, but he gets asked for advice about it all the time.
"I shouldn't have to do this," he said. "It's just totally made up, out of whole cloth. It's just nonsense. But it is literally scaring people and having an impact on what they're doing."
Space is fairly dangerous. I like to say that the universe is trying to kill us.
–Phil Plait
He worries about real threats to Earth, verified by science. There's not much we can do about extremely improbable threats like black holes, exploding stars and gamma-ray bursts, Plait said. But the most likely threat is from asteroids, which most scientists now accept as the instrument of doom for the dinosaurs. Every shooting star is a warning sign.
"Asteroid impacts are rare; they don't happen that much," Plait said. "But we just had something about the size of an SUV explode over California."
If we sit around and do nothing long enough, a big asteroid hit is almost certain, Plait said, so let's do something.
"We have to find these asteroids," he said. "We have to find out, if we see one, how do we do this? Do we blow it up? Do we slam it? Do we tow it?"
But the key, he said, is using science as a tool, instead of ignorance and phony mythology.
"It's so easy to fool human beings," he said. "And science circumvents that as long as you use it correctly."
Dwayne Brown
Headquarters, Washington

Nancy Neal Jones
Goddard Space Flight Center, Greenbelt, Md.
April 18, 2012
RELEASE : 12-121
NASA Mission Wants Amateur Astronomers to Target Asteroids
WASHINGTON -- A new NASA outreach project will enlist the help of amateur astronomers to discover near-Earth objects (NEOs) and study their characteristics. NEOs are asteroids with orbits that occasionally bring them close to the Earth. 

Starting today, a new citizen science project called "Target Asteroids!" will support NASA's Origins Spectral Interpretation Resource Identification Security - Regolith Explorer (OSIRIS-REx) mission objectives to improve basic scientific understanding of NEOs. OSIRIS-REx is scheduled for launch in 2016 and will study material from an asteroid. 

Amateur astronomers will help better characterize the population of NEOs, including their position, motion, rotation and changes in the intensity of light they emit. Professional astronomers will use this information to refine theoretical models of asteroids, improving their understanding about asteroids similar to the one OSIRIS-Rex will encounter in 2019, designated 1999 RQ36. 

OSIRIS-REx will map the asteroid's global properties, measure non-gravitational forces and provide observations that can be compared with data obtained by telescope observations from Earth. In 2023, OSIRIS-REx will return back to Earth at least 2.11 ounces (60 grams) of surface material from the asteroid. 

Target Asteroids! data will be useful for comparisons with actual mission data. The project team plans to expand participants in 2014 to students and teachers. 

"Although few amateur astronomers have the capability to observe 1999 RQ36 itself, they do have the capability to observe other targets," said Jason Dworkin, OSIRIS-REx project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. 

Previous observations indicate 1999 RQ36 is made of primitive materials. OSIRIS-REx will supply a wealth of information about the asteroid's composition and structure. Data also will provide new insights into the nature of the early solar system and its evolution, orbits of NEOs and their impact risks, and the building blocks that led to life on Earth. 

Amateur astronomers long have provided NEO tracking observations in support of NASA's NEO Observation Program. A better understanding of NEOs is a critically important precursor in the selection and targeting of future asteroid missions. 

"For well over 10 years, amateurs have been important contributors in the refinement of orbits for newly discovered near-Earth objects," said Edward Beshore, deputy principal investigator for the OSIRIS-REx mission at the University of Arizona in Tucson. 

NASA's Goddard Space Flight Center in Greenbelt, Md., will provide overall mission management, systems engineering and safety and mission assurance for OSIRIS-REx. Dante Lauretta is the mission's principal investigator at the University of Arizona. Lockheed Martin Space Systems in Denver will build the spacecraft. OSIRIS-REx is the third mission in NASA's New Frontiers Program. NASA's Marshall Space Flight Center in Huntsville, Ala., manages New Frontiers for the agency's Science Mission Directorate in Washington. 

For more information about NASA, visit: 

For more information on Target Asteroids! and OSIRIS-REx, visit: 
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Tucson scientist reveals new dangers of asteroid impact

Posted: Nov 5, 2010 6:00 AM 

TUCSON - New research by a Tucson scientist reveals shocking details about asteroids and our planet. The study shows certain asteroids could be more destructive than we ever thought.
Elisabetta Pierazzo, a senior scientist at the Planetary Science Institute, studied asteroids ranging from 500 meters to one kilometer. Unlike the one that killed the dinosaurs, these asteroids would not cause mass extinction.
"There is a chance that it could be a large enough impact to destabilize current civilization. And there's never been a quantification of what does that mean," Pierazzo said.
Pierazzo's study shows what might happen if one of these medium size asteroids landed in the ocean. She created simulations, looked at the data and found that kind of impact would have world-wide repercussions.
"You're going to throw a lot of water vapor and, with that, you're going to throw a lot of chloride and bromide into the upper atmosphere," Pierazzo said.
Those chemicals could destroy at least 60 percent of the ozone layer all over the world. People and plants would have little natural protection from harmful ultraviolet rays, forcing us to stay inside or wear sunscreen and hats all the time. However, plants and fish would be stuck unprotected in the sun.
"We are going to have less food to eat and it's going to be a major problem for this world," Pierazzo said.
Edward Beshore, Senior Staff Scientist at the Lunar and Planetary Laboratory and Principle Investigator for the Catalina Sky Survey, spends his days looking for asteroids.
"Most of the objects we find are about 100 to 200 meters across," Beshore said.
As for the asteroids from Pierazzo's study, Beshore says they spot about 50 a year. A small number of them come within five million miles of the earth's orbit. Those can be unpredictable.
"If they cross the orbit of the earth, they are potentially hazardous asteroids that we really need to keep our eye on," Beshore said.
In all, there are a couple hundred of those potentially hazardous, medium sized (500m to 1 km) asteroids out there. On average, asteroids that size hit the earth about every 25,000 to one million years.

Impact of large asteroid may cause disruption of Earth ozonosphere

Recently scientists all over the world have presented many models describing a collision of the Earth with an asteroid or a comet. All of us can imagine the consequences of such a collision. That is a powerful impact wave, a huge tsunami from the body falling into the ocean and the so-called “impact” winter and “firey” rain consisting of material from the Earth’s crust blasted to the edge of the atmosphere with a subsequent rain of meteors back to the Earth. All these scenarios are possible with the falling of a large body similar to that which possibly killed off the dinosaurs at the Cretaceous-Tertiary boundary (the so-called K-T Event).

Is this all we can expect from such a catastrophic scenario? Or do we need to prepare for something more? As studies by the American scientists of the Planetary Science Institute (PSI) have shown, one more biosphere-destroying event will be the destruction of the planet’s ozone layer. The group, under the direction of Elizabeth Pierazzo, generated two models describing the fall of asteroids 500 and 1000 meters in diameter into the ocean (depth of 4000 meters). From their analysis of the data the scientists came to some conclusions about the catastrophic consequences of the ejection of huge quantities of hot water vapor into the atmosphere. After the water vapor, the liberation of huge volumes of chlorides and bromides will continue the process of destroying the ozone layer. As a result of these events, there will be a global exhaustion of the ozone layer, and Earth life will be defenseless for years.

The UVI (ultraviolet index) may be over 20 for several months after Earth is hit by a 500 meter asteroid. A reading of 10 is dangerous to humans, and 20 is the maximum value ever recorded on Earth. Under such radiation, a person can get burned even after only five minutes in the sun. Even more serious are the facts associated with the impact of a kilometer-sized asteroid. The brightness of the ultraviolet radiation will reach a huge value – 56! A person without protection in the open sunlight would literally burn up. The ultraviolet intensity would gradually decrease, but over the course of two years its level would remain over 20.

During this time most of the plant and animal life on Earth would perish; in countries where there are not huge reserves of foodstuffs, hunger would become a problem. All this is without calculating in the catastrophe which a huge tsunami would cause.

All these data are not to scare the people of the Earth, but, instead, they have the purpose of bringing understanding of what we must be prepared for, if we want to preserve our civilization at our modern level of development, and not plunge it into chaos because we couldn’t take a hit from space.


New observations of Apophis

D. Tholen, M. Micheli, G. Elliott, UH Institute for Astronomy
January 31, 2011, American astronomers at the University of Hawaii took the first pictures of the well-known asteroid Apophis on the way to its next passage by the Earth, which will take place January 9, 2013. To observe this still faint object, scientists used the 2.2 meter telescope of the university observatory located on the top of the Hawaiian volcano, Mauna Kea. These observations were complicated not only by the faintness of the object, but also by the smallelongation of the asteroid.

With these observations begins a new round of study of this interesting and potentially hazardous object. Remember that April 13, 2029 it passes closer to the Earth than geostationary satellites, at an elevation of about 30,000 km, and will be visible to the unaided eye. This passage will not be dangerous for our planet. The danger may be in the asteroid flying through the so called “keyhole” – a zone of width of only 600 km. If that happens, the Earth’s own gravitational influence will bring the asteroid into an orbit of resonant return, and in 2036 the asteroid will collide with the Earth. The probabilty of such an event is very small, but it does exist. The fall of a body with a diameter on the order of 270 meters can have catastrophic consequences for the Earth. We still have time and we must protect ourselves regardless of how events might develop. But we must do this before the 2029 passage, otherwise the complexity of this already difficult task will increase many times.


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