Wednesday, February 9, 2011

Asteroid Apophis is labeled a Near Earth Object
Filed under: Asteroid Apophis latest
08 February 2011
Asteroid Apophis will come very close to earth in 2029 and possibly impact in the year 2036. That may seem like a long time from now, but it is just around the corner. Instead of worrying about 2012, start to worry that we don’t have a good program designed to track potential asteroid hazards. How many times do we hear about asteroids zooming very close to earth and we did not know that it was even coming? We know Asteroid Apophis is coming…but what are they not telling us?
Apophis will come within 18,000 miles from earth on Friday, April 13th, 2036. That amount of miles is actually very, very close and it will be visible to the naked eye. You thought Halley’s comet was the talk of the world in the 1980’s…just wait until this Asteroid Apophis comes knocking on our door.
Asteroid Apophis is 1,000 feet in diameter, which is about 90 stories tall and weighs 25 million tons. If this asteroid hits anywhere on earth it would be 68,000 times the force that the atomic bomb that destroyed Hiroshima.
NASA labeled Apophis as a Near Earth Object. Lets just hope it stays in that label and not become an impact asteroid.
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Astronomers predict Asteroid Apophis to hit in 2036
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31 January 2011
Some Russian astronomers are recalculating Asteroid Apophis’s trajectory and now say that there is a strong possibility that it will slam into Earth on April 13th, 2036. The name Apophis was given to this asteroid, named after the Egyptian god Apep, aka “The Uncreator”.
Professor Leonid Sokolov of the Petersburg State University was quoted as saying, “Apophis will approach Earth at a distance of 37,000 to 38,000 kilometers on April 13, 2029. Its likely collision with Earth may occur on April 13, 2036,” during an interview with Russian state television and broadcast by the Russian RIA Novosti News.
Everyday more and more astronomers are waking up to the idea that perhaps the Earth is in danger. From this a summit will be held in July to discuss joining forces against these potential hazardous asteroids.
More to come.
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Asteroid Apophis May Kill Satellites
Filed under: Asteroid Apophis latest
21 November 2010
NASA predicts On Friday the 13th, April 2029 asteroid 99942 Apophis will be perilously close to earth and will be within range to wipe out geosynchronous satellites.
Quoting NASA:
The future for Apophis on Friday, April 13 of 2029 includes an approach to Earth no closer than 29,470 km (18,300 miles, or 5.6 Earth radii from the center, or 4.6 Earth-radii from the surface) over the mid-Atlantic, appearing to the naked eye as a moderately bright point of light moving rapidly across the sky. Depending on its mechanical nature, it could experience shape or spin-state alteration due to tidal forces caused by Earth’s gravity field.
This is within the distance of Earth’s geosynchronous satellites. However, because Apophis will pass interior to the positions of these satellites at closest approach, in a plane inclined at 40 degrees to the Earth’s equator and passing outside the equatorial geosynchronous zone when crossing the equatorial plane, it does not threaten the satellites in that heavily populated region.
The close approach in 2029 will substantially alter the object’s orbit, making predictions uncertain without more data. “If we get radar ranging in 2013 [the next good opportunity], we should be able to predict the location of 2004 MN4 out to at least 2070.” said Jon Giorgini of JPL. Apophis will pass within 0.09666 AU (14.4 million km) of the Earth in 2013 allowing astronomers to refine the trajectory for future close passes.
In July 2005, former Apollo astronaut Rusty Schweickart, as chairman of the B612 Foundation, formally asked NASA to investigate the possibility that the asteroid’s post-2029 orbit could be in orbital resonance with Earth, which would increase the probability of future impacts. Schweickart asked for an investigation of the necessity of placing a transponder on the asteroid for more accurate tracking of how its orbit is affected by the Yarkovsky effect.
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NASA Prepares For Huge Asteroid Encounter
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31 August 2010
NASA has commenced the countdown for its Dawn spacecraft’s brush with the behemoth asteroid Vesta, slated for less than a year from now.
Commencing next July, Dawn will orbit Vesta for a year, carrying a elaborate study and becoming the 1st spacecraft ever to orbit a body in the asteroid belt. Former missions have depicted us a fistful of asteroids, but Vesta will be peculiar, scientists say.
“Vesta is going to amaze us,” said Marc Rayman, Dawn’s chief engineer at NASA’s Jet Propulsion Laboratory.
At 350 miles (565 km) across, Vesta is about a globe unto itself. It’s the second-largest body in the asteroid belt, bearing about 10 percent of the entire belt’s mass. The asteroid Ceres, so big it is believed a dwarf planet, is the only belt object greater than Vesta.
“It’s a big, rocky, terrestrial-type body more likely alike to the moon and Mercury than to the little bits of rocks we’ve flown by in the past,” Rayman said of Vesta. “For example, there’s a large crater at Vesta’s south pole, and inside the crater is a mountain bigger than asteroid Eros.”
Researchers hope Dawn’s mission will assist them interpret how planets form. Astronomers believe, after all, that Vesta was in the process of becoming a experienced planet when Jupiter disrupted its growth. The gas giant’s gravity stirred up the material in the asteroid belt so objects there could no longer coalesce.
Dawn, which of late set a record for the all-time greatest speed boost for a spacecraft engine, will start its Vesta surveys out slow. Its first orbits will be high and leisurely, and the craft will take days to loop around Vesta at altitudes of about 1,700 miles (2,735 km).
After taking pictures and gathering data from up high, Dawn will spiral down to lower and lower orbits, eventually settling in a little more than 100 miles (nearly 161 km) high lower than satellites orbiting Earth.
The great Vesta view Dawn gets won’t be restricted to astronomers: Researchers will quickly combine the images the probe captures into a movie, allowing the mission team and public all to vicariously ride along.
After a year orbiting Vesta, Dawn will move on to take a look at the asteroid belt’s largest body: the dwarf planet Ceres.
Dawn’s mission follows on the heels of several others, as astronomers have become increasingly interested lately in near-Earth objects.
For example, the European Space Agency’s Rosetta spacecraft just beamed back pictures of Lutetia, which at 62 miles (100 km) wide is the largest asteroid yet visited by a spacecraft.
And in June, the Japanese space agency’s Hayabusa probe returned to Earth after a seven-year journey to the asteroid Itokawa. Hayabusa’s goal was to return samples of an asteroid to Earth, which would be a first and it may have done so, though the jury is still out.
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Trojan Asteroid Found
Filed under: Asteroid Apophis latest
13 August 2010
Astronomers have discovered a new asteroid in a region of Neptune’s orbit where no previous object was known to exist — a so-called gravitational “dead zone.”
The asteroid, which follows Neptune’s orbit around the sun, may help shed light on fundamental questions about planetary formation and migration.
The asteroid, classified as a Trojan, was found in a difficult-to-detect area near Neptune, known as the Lagrangian point L5. Lagrangian points are five areas in space where the gravitational tugs from two relatively massive bodies — such as Neptune and the sun — balance out. This allows smaller bodies, like asteroids, to remain stable and fixed in synch with the planet’s orbit, as they orbit the sun.
Trojan asteroids, named after the famous war in Greek mythology that was waged by the ancient Greeks against the city of Troy, share a planet’s orbit around the sun, but do not collide with it because they remain safely near the Lagrangian regions.
Trojan asteroids have previously been found in some of the stable points near Neptune and Jupiter, but this is the first discovery of a Trojan in Neptune’s L5 region.
“We believe Neptune Trojans outnumber the Jupiter Trojans and the main-belt asteroids between Mars and Jupiter,” Scott Sheppard of the Carnegie Institution in Washington, D.C., told SPACE.com. “If Neptune was where the main-belt was, we’d know thousands of these objects.”
He added that thousands of Trojan asteroids are associated with Jupiter.
Stable regions
At Neptune, the L4 and L5 regions are 60 degrees along the planet̢۪s 360-degree orbital path, ahead and behind the planet respectively. In this configuration, dust grains and other small bodies are able to collect and remain there.
Neptune Trojans are very faint because they are so far away from the Earth and the sun, making them difficult to detect. Astronomers Scott Sheppard of the Carnegie Institution in Washington, D.C., and Chad Trujillo of the Gemini Observatory in Hilo, Hawaii, discovered the Trojan asteroid, 2008 LC18, through an innovative observational strategy.
Using images from the digitized all-sky survey, the astronomers identified pockets of space in the stable regions where dust clouds in our galaxy blocked out the background starlight that crowds the galaxy’s plane. This gave the researchers an observational window to observe asteroids in the foreground.
The L5 Neptune Trojan was found using the 8.2-meter Japanese Subaru Telescope in Hawaii. They then used the Carnegie 6.5 meter Magellan Telescope to observe and determine the object’s orbit.
Sheppard and Trujillo had previously discovered three of the six known Neptune Trojans in the L4 region in the last several years. The L5 region is much more difficult to observe.
“You’re looking at the center of the Milky Way galaxy, so there are a lot of stars and dust clouds there” [in the background], Sheppard told SPACE.com.
The astronomers’ discovery proves that at least one Trojan asteroid exists in the L5 region of Neptune. And while the asteroid is too faint to be able to determine its composition, Sheppard and Trujillo were able to gather other details about the mysterious object.
“We estimate that the new Neptune Trojan has a diameter of about 62 miles (100 km), and that there are about 150 Neptune Trojans of similar size at L5,” Sheppard said. “It matches the population estimates for the L4 Neptune stability regions.”
A window to the past
The 2008 LC18 Trojan asteroid always trails behind Neptune and takes the same amount of time to circle the sun as the gas giant planet, but there is one key difference between the orbits of the objects, Sheppard said.
The asteroid has a highly inclined orbit, meaning for half of its orbit the asteroid swings north of Neptune and for the other half it sits south relative to the plane of the solar system. Even though it swings above and below this plane, the angle between the asteroid and Neptune relative to the sun remains at 60 degrees.
This is similar to several asteroids found in the L4 region, which suggests that the objects were captured into these stable regions in the early years of the solar system.
During this time, Neptune was moving on a different orbit than it is now, said Sheppard.
“This is a high-inclination object, as it would be if Neptune was on a much more eccentric orbit in the past,” Sheppard said. “This supports the idea that the solar system was much more chaotic, and that giant planets didn’t form where they are now, but migrated there.”
Planets likely captured Trojan asteroids through a slow, smooth process of planetary migration, or, as giant planets like Neptune and Jupiter settled into their obits, their gravitational attraction may have trapped these objects in their current locations.
“In the distant past, Neptune likely migrated out several AU (astronomical units) and had a much more eccentric and chaotic orbit than it has now,” Sheppard said.
The research from this study will be published in the Aug. 13 issue of the journal Science.
Source: http://www.csmonitor.com/Science/2010/0813/Trojan-asteroid-detected-in-Neptune-s-dead-zone
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NASA Asteroid Apophis Update
Filed under: Asteroid Apophis latest
13 July 2010
SUMMARY
Researchers at NASA/JPL, Caltech, and Arecibo Observatory have released the results of radar observations of the potentially hazardous asteroid 99942 Apophis, along with an in-depth analysis of its motion. The research will affect how and when scientists measure, predict, or consider modifying the asteroid’s motion. The paper has been accepted for publication in the science journal “Icarus” and was presented at the AAS/DPS conference in Orlando, Florida in October of 2007. The Apophis study was led by Jon Giorgini, a senior analyst in JPL’s Solar System Dynamics group and member of the radar team that observed Apophis.
The analysis of Apophis previews situations likely to be encountered with NEAs yet to be discovered: a close approach that is not dangerous (like Apophis in 2029) nonetheless close enough to obscure the proximity and the danger of a later approach (like Apophis in 2036) by amplifying trajectory prediction uncertainties caused by difficult-to-observe physical characteristics interacting with solar radiation as well as other factors.
BACKGROUND
Upon its discovery in 2004, Apophis was briefly estimated to have a 2.7% chance of impacting the Earth in 2029. Additional measurements later showed there was no impact risk at that time from the 210-330 meter (690-1080 foot) diameter object, identified spectroscopically as an Sq type similar to LL chondritic meteorites. However, there will be a historically close approach to the Earth, estimated to be a 1 in 800 year event (on average, for an object of that size).
The Arecibo planetary radar telescope subsequently detected the asteroid at distances of 27-40 million km (17-25 million miles; 0.192-0.268 AU) in 2005 and 2006. Polarization ratios indicate Apophis appears to be smoother than most NEAs at 13-cm scales. Including the high precision radar measurements in a new orbit solution reduced the uncertainty in Apophis’ predicted location in 2029 by 98%.
While trajectory knowledge was substantially corrected by the Arecibo data, a small estimated chance of impact (less than 1 in 45,000 using standard dynamical models) remained for April 13, 2036. With Apophis probably too close to the Sun to be measured by optical telescopes until 2011, and too distant for useful radar measurement until 2013, the underlying physics of Apophis’ motion were considered to better understand the hazard.
RESULTS OF THE STUDY
(1) Extending the “Standard Dynamical Model”
Trajectory predictions for asteroids are normally based on a standard model of the solar system that includes the gravity of the Sun, Moon, other planets, and the three largest asteroids.
However, additional factors can influence the predicted motion in ways that depend on rarely known details, such as the spin of the asteroid, its mass, the way it reflects and absorbs sun-light, radiates heat, and the gravitational pull of other asteroids passing nearby. These were examined, along with the effect of Earth’s non-uniform gravity field during encounters, and limitations of the computer hardware performing the calculations.
One would normally look for the influence of such factors as they gradually alter the trajectory over years. But, for Apophis, the changes remain small until amplified by passage through Earth’s gravity field during the historically close approach in 2029.
For example, the team found solar energy can cause between 20 and 740 km (12 and 460 miles) of position change over the next 22 years leading into the 2029 Earth encounter. But, only 7 years later, the effect on Apophis’ predicted position can grow to between 520,000 and 30 million km (323,000 and 18.6 million miles; 0.0035-0.2 AU). This range makes it difficult to predict if Apophis will even have a close encounter with Earth in 2036 when the orbital paths intersect.
It was found that small uncertainties in the masses and positions of the planets and Sun can cause up to 23 Earth radii of prediction error for Apophis by 2036.
The standard model of the Earth as a point mass can introduce up to 2.9 Earth radii of prediction error by 2036; at least the Earth’s oblateness must be considered to predict an impact.
The gravity of other asteroids can cause up to 2.3 Earth radii of prediction uncertainty for Apophis.
By considering the range of Apophis’ physical characteristics and these error sources, it was determined what observations prior to 2029 will most effectively reduce prediction uncertainties. Observing criteria were developed that, if satisfied, could permit eliminating the 2036 impact possibility without further physical characterization of Apophis.
Such observations could reduce the need for a visit by an expensive spacecraft and reduce the risk of Apophis being prematurely eliminated as a hazard under the standard model, only to drift back into the hazard classification system years later as the smaller, unmodeled forces act upon it.
(2) Mitigation
Mitigation was not specifically studied, but the team found small variations in the energy absorption and reflection properties of Apophis’ surface are sufficient to cause enough trajectory change to obscure the difference between an impact and a miss in 2036. Changing the amount of energy Apophis absorbs by half a percent as late as 2018 – for example by covering a 40 x 40 meter (130 x 130 foot) patch with lightweight reflective materials (an 8 kg payload) – can change its position in 2036 by a minimum of one Earth radius.
A change somewhat greater than this minimum would be required to allow for prediction uncertainties. For Apophis, scaling up to distribute 250 kg (550 pounds) of a reflective or absorptive material (similar to the carbon fiber mesh being considered for solar sails) across the surface could use the existing radiation forces to produce a 6-sigma trajectory change, moving at least “99.9999998″ percent of the statistically possible trajectories away from the Earth in just 18 years.
While no deflection is expected to be necessary, the team’s research demonstrates that any deflection method must produce a change known in advance to be greater than all the error sources in the prediction, including some greater than those considered with the standard model.
(3) Impact probability
The study did NOT compute new impact probabilities. This is because important physical parameters (such as mass and spin pole) that affect its trajectory have not yet been measured and hence there are no associated probability distributions. The study characterizes how the Standard Dynamical Model can over or under-estimate impact probability for those objects having close planetary encounters prior to the potential impact.
The situation is similar to having 6 apples (the measured Apophis parameters) and 6 boxes whose contents are unknown (the unmeasured Apophis parameters), then trying to compute the probability one has a total of 12 apples (impact probability). The result reflects back what is assumed about the unknown contents of the boxes, but doesn’t reveal new information. The contents of the boxes must be observed (measured) to learn something new.
For similar reasons, the Apophis study instead uses the minimum and maximum range-of-effect in place of computing impact probabilities to provide reasonable criteria for excluding impact in the absence of detailed physical knowledge, once new position measurements are obtained at six key times.
(4) Non-Apophis Conclusions
Aspects of the study relevant to asteroids other than Apophis:
The Standard Dynamical Model can misestimate impact risk for the more numerous sub-km objects preceded by close planetary encounter(s). This problem might be addressed by reassessing impact potential after planetary encounters, given new measurements.
The minimum-maximum effect of unmeasured parameters can provide enough information to exclude threats in certain cases, even if a realistic impact probability cannot be computed.
Amplification of small trajectory offsets makes valid prediction across a close-encounter difficult without physical knowledge, but offers the potential to redirect the entire uncertainty region and has significant implications for costly spacecraft missions.
A deflection effort must be known in advance to produce change greater than predicted uncertainties due to ALL parameters, not only the Standard Dynamical Model. For example, if a method produces 10 Earth-radii of change, but prediction uncertainties from all sources are 20 Earth-radii, the deflection would move the asteroid around within the noise, producing an unpredicted result or even a new hazard.
The Apophis situation has predictability problems essentially the same as previously described in “Science” for 29075 (1950 DA), but occurring more severely: in as little as 2-3 decades, rather than the 880 year prediction of that case.
FUTURE
The future for Apophis on Friday, April 13 of 2029 includes an approach to Earth no closer than 29,470 km (18,300 miles, or 5.6 Earth radii from the center, or 4.6 Earth-radii from the surface) over the mid-Atlantic, appearing to the naked eye as a moderately bright point of light moving rapidly across the sky. Depending on its mechanical nature, it could experience shape or spin-state alteration due to tidal forces caused by Earth’s gravity field.
This is within the distance of Earth’s geosynchronous satellites. However, because Apophis will pass interior to the positions of these satellites at closest approach, in a plane inclined at 40 degrees to the Earth’s equator and passing outside the equatorial geosynchronous zone when crossing the equatorial plane, it does not threaten the satellites in that heavily populated region.
Using criteria developed in this research, new measurements possible in 2013 (if not 2011) will likely confirm that in 2036 Apophis will quietly pass more than 49 million km (30.5 million miles; 0.32 AU) from Earth on Easter Sunday of that year (April 13).
CREDITS
In addition to Giorgini, co-authors of the report include Dr. Lance A. M. Benner and Dr. Steven J. Ostro of JPL; Dr. Michael C. Nolan, Arecibo Observatory, Puerto Rico, and Michael W. Busch of the California Institute of Technology.
Arecibo Observatory is operated by Cornell University under a cooperative agreement with the National Science Foundation. JPL is managed for NASA by the California Institute of Technology in Pasadena.
Source:
http://neo.jpl.nasa.gov/apophis/
Here is the PDF from http://neo.jpl.nasa.gov/apophis/Apophis_PUBLISHED_PAPER.pdf
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Killer Asteroid Apophis
Filed under: Asteroid Apophis latest
23 June 2010
By MICHIO KAKU
Anatoly Perminov, head of the Russian Space Agency, caught scientists off guard back in January when he called for a closed meeting of Russian

ASTEROID1
scientists to counter a killer asteroid headed our way. He said that a potential impact from the asteroid Apothis around 2036 could kill hundreds of thousands of people. Immediately this conjured up images of Bruce Willis and his space cowboys riding the Space Shuttle to blow up a comet in the movie “Armageddon.” Scientists, realizing that the danger is slight but real, have in fact seriously proposed various ways in which to deflect the asteroid.
As asteroids go, Apophis is a whopper, measuring 1,000 feet across, about the size of the Rose Bowl. In 2029 it will make its first pass around the earth, so close that it will travel beneath our communication satellites. In fact, you might see it whiz by overhead with binoculars. Depending on how it whips around the earth, there is a slight chance it might actually hit the earth when it returns in 2036 (but the latest calculations only show a one in a hundred thousand chance of impact).
The Russians take such a threat seriously, since a “city buster” hit Tunguska, Siberia, in 1908, flattening about a thousand square miles of forest, destroying about 100 million trees, and leaving a huge scar in the Earth. The object that struck Siberia was probably only 100 feet across, yet it created a blast about 1,000 times greater than the Hiroshima bomb. The shock waves were so intense they were detected in Europe. It created a strange glow which spread over Asia and Europe so that you could read the London papers at night. If it had hit Moscow, it would have completely flattened that city and beyond. A city-buster like that happens once every 100-300 years, with most of them hitting the oceans.
A hit from Apothis, however, would be another story. It would be a “country buster,” capable of creating fire storms, shock waves, and a rain of fiery debris that would destroy an area almost the size of France, or perhaps the entire Northeast of the U.S. The energy of the impact would be roughly 100,000 times that of the Hiroshima bomb. If it hits the Pacific Ocean, it could also generate a huge tidal wave, a gigantic wall of water that could swamp most coastal cities in the Americas and Asia. An impact from an Apophis-like asteroid is estimated to happen once in a thousand years. (The worst case scenario, however, would be an impact from a “planet buster” as little as six miles across, like the one that hit Mexico and probably wiped out the dinosaurs 65 million years ago.)
Plans to counter such a hypothetical threat, however, are sketchy. A staple of science fiction is to send the Space Shuttle to blow it up. Bad idea.
First, this might only crack the asteroid, so you would have a swarm of deadly mini-asteroids headed your way. Second, the Space Shuttle can only circle the Earth; it is incapable of reaching deep space to intercept the asteroid. And it is going to be phased out this year anyway and a replacement won’t be ready for about five years.
Several proposals made by scientists are currently being studied. One likely scenario is to nudge the asteroid while it is still in deep space so that it eventually misses the Earth. This deflection might be done via rockets to push the asteroid years before it passes the Earth. Or, the gravity of the spacecraft itself may be used to gently tug on its trajectory. Yet another proposal is to use mirrors and even paint to increase the pressure of sunlight so that, over decades, its trajectory is modified.
At present, none of the hardware for such a mission exists, so we will be helpless for years if a real threat emerges. And any serious proposal will require tens of billions of dollars, for new booster rockets and the complex machinery to deflect the asteroid.
But given these hard economic times, money is scarce even to maintain the current space program. The Augustine Report on the future of space travel, commissioned by NASA and presented to President Obama in October, stated that manned missions to the moon and Mars were “unsustainable” without a new injection of funds. However, it did leave open the possibility of landing on an asteroid. So one real possibility is to land a probe on the asteroid in 2029 so that scientists can study its properties as well as get a free ride through the solar system. We know so little about Apothis that it might be a solid object or just a loose collection of rocky debris held together by gravity.
Some conspiracy theorists have raised the dark possibility that any nation that can deflect an asteroid could also send it hurtling toward its enemies. But such a weapon is simply too unstable and unreliable to be taken seriously.
Indeed, scientists are applauding the Russian Space Agency for addressing the issue, even if the danger from Apophis is very slight. Sooner or later, we will face a catastrophic threat from space. Of all the possible threats, only a gigantic asteroid hit can destroy the entire planet. If we prepare now, we better our odds of survival. The dinosaurs never knew what hit them.
http://online.wsj.com/article/SB10001424052748703580904574638230276797924.html
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Asteroids
Filed under: Asteroid Apophis latest
13 June 2010
Yesterday, the Japanese Aerospace Exploration Agency (JAXA) is planning to bring the Hayabusa probe down to Earth in Australia, hopefully bringing bits of an asteroid down with it.
The probe visited asteroid 25143 Itokawa in 2005 and attempted to collect samples of dust and pebbles from the rock. Because of glitches during the sample collection, scientists are unsure exactly what they will find when they open Hayabusa’s sealed sampling chamber.
But if successful, this will mark the first time asteroid samples are returned to Earth for analysis.
Although missions to celestial bodies such as Mars or the moon may sound more exciting than a mission to asteroid 25143 Itokawa, scientists say we have much to learn from these irregularly-shaped rocks that roll through our solar system. Here are 5 reasons why we should care about asteroids:
1. They will tell us about the origins of our solar system.
The materials in asteroids represent the building blocks of the planets,” said Carol Raymond, deputy principal investigator on NASA’s Dawn mission, which lifted off in 2007 and will visit asteroid Vesta in 2011 and dwarf planet Ceres in 2015. Because of the position of the asteroid belt that lies between the rocky inner planets and the gas giants of the outer solar system, the materials found there may hold clues as to why the planets are so diverse today.
For example, although Ceres and Vesta formed at roughly the same time – within the first 10 million years of the solar system’s existence – they have very different compositions now. Vesta, at some point, melted completely and then resolidified, so it is now smooth. Meanwhile Ceres does not show signs of having gone through this melting.
It’s possible, Raymond said, that Vesta experienced more collisions, or that it had a high amount of a radioactive form of aluminum that would have given off heat as it underwent radioactive decay. By studying each asteroid, scientists will be able to solve this mystery. 2. They will help us understand more about the origin of life. Scientists do not fully understand how the first life forms arose on Earth from non-living organic matter, and asteroids may help us learn more about this puzzle.
Asteroids such as 2 Pallas and 10 Hygiea, which are both believed to have had water in the past, appear to have organic (carbon-based) compounds on them, Raymond said. Today, these asteroids have a more primitive chemical composition than Earth has – they are more similar to the conditions that existed in the solar system’s younger years. By studying them, we may learn about how life arose on our own planet.
“There are conditions that may have been conducive to life in the past,” Raymond said.
Plus, scientists think asteroids that landed on Earth long ago may have deposited some of the building blocks that helped start life here.
3. We may want to mine near-earth asteroids for metals. “There is a keen interest in going to asteroids in the near-earth belt,” Raymond said. “They could be sources of valuable metals.” To investigate the feasibility of such operations, we need to know more about asteroid composition and the technical aspects of traveling to them.
Besides the opportunity for mining, these asteroids are also interesting from a scientific perspective, because studying them complements our studies of the major planets, Raymond said. Analyzing the differences between the planets and the smaller asteroids is like taking slices of the solar system at different times during its formation.
4. They may someday threaten to collide with Earth. Because some asteroids orbit around the sun in paths shaped like elongated ovals, they cross Earth’s orbit every so often. And sometimes, they come very close to Earth itself. For example, in January, asteroid 2010 AL30 passed within about 80,000 miles (130,000 km) of Earth.
But 2010 AL30 was just at 36 feet (11 meters) wide. More worrisome is the prediction that asteroid Apophis will come very close to Earth on April 13, 2036. Although NASA predicts that it will pass no closer than 18,300 miles above Earth’s surface, Apophis is larger than two football fields. While that’s not big enough to create Hollywood-style global devastation, it could cause significant regional damage, were it ever to strike Earth. 5. Astronauts may go visit one, according to Obama’s new plan for NASA.
In April, President Barack Obama announced the next goal for Americans in space: visiting an asteroid by 2025.
In a panel discussion in April, astrophysicist John Grunsfeld – a former NASA astronaut who flew on five shuttle missions – suggested that one goal might be sending humans to purposely move an asteroid, to nudge the space rock to change its trajectory. Such a feat, he said, would show that humanity could deflect a space rock if one threatened to crash into the planet.
(Source: Space.com)
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Reasons to Care About Asteroids
Filed under: Asteroid Apophis latest
12 June 2010
On Sunday, the Japanese Aerospace Exploration Agency (JAXA) is planning to bring the Hayabusa probe down to Earth in Australia, hopefully bringing bits of an asteroid down with it.
The probe visited asteroid 25143 Itokawa in 2005 and attempted to collect samples of dust and pebbles from the rock. Because of glitches during the sample collection, scientists are unsure exactly what they will find when they open Hayabusa’s sealed sampling chamber.
But if successful, this will mark the first time asteroid samples are returned to Earth for analysis.
Although missions to celestial bodies such as Mars or the moon may sound more exciting than a mission to asteroid 25143 Itokawa, scientists say we have much to learn from these irregularly-shaped rocks that roll through our solar system. Here are 5 reasons why we should care about asteroids:
1. They will tell us about the origins of our solar system.
“The materials in asteroids represent the building blocks of the planets,” said Carol Raymond,deputy principal investigator on NASA’s Dawn mission, which lifted off in 2007 and will visit asteroid Vesta in 2011 and dwarf planet Ceres in 2015. Because of the position of the asteroid belt that lies between the rocky inner planets and the gas giants of the outer solar system, the materials found there may hold clues as to why the planets are so diverse today.
For example, although Ceres and Vesta formed at roughly the same time – within the first 10 million years of the solar system’s existence – they have very different compositions now. Vesta, at some point, melted completely and then resolidified, so it is now smooth. Meanwhile Ceres does not show signs of having gone through this melting.
It’s possible, Raymond said, that Vesta experienced more collisions, or that it had a high amount of a radioactive form of aluminum that would have given off heat as it underwent radioactive decay. By studying each asteroid, scientists will be able to solve this mystery.
2. They will help us understand more about the origin of life.
Scientists do not fully understand how the first life forms arose on Earth from non-living organic matter, and asteroids may help us learn more about this puzzle.
Asteroids such as 2 Pallas and 10 Hygiea, which are both believed to have had water in the past, appear to have organic (carbon-based) compounds on them, Raymond said. Today, these asteroids have a more primitive chemical composition than Earth has – they are more similar to the conditions that existed in the solar system’s younger years. By studying them, we may learn about how life arose on our own planet.
“There are conditions that may have been conducive to life in the past,” Raymond said.
Plus, scientists think asteroids that landed on Earth long ago may have deposited some of the building blocks that helped start life here.
3. We may want to mine near-earth asteroids for metals.
“There is a keen interest in going to asteroids in the near-earth belt,” Raymond said. “They could be sources of valuable metals.” To investigate the feasibility of such operations, we need to know more about asteroid composition and the technical aspects of traveling to them.
Besides the opportunity for mining, these asteroids are also interesting from a scientific perspective, because studying them complements our studies of the major planets, Raymond said. Analyzing the differences between the planets and the smaller asteroids is like taking slices of the solar system at different times during its formation.
4. They may someday threaten to collide with Earth.
Because some asteroids orbit around the sun in paths shaped like elongated ovals, they cross Earth’s orbit every so often. And sometimes, they come very close to Earth itself. For example, in January, asteroid 2010 AL30 passed within about 80,000 miles (130,000 km) of Earth.
But 2010 AL30 was just at 36 feet (11 meters) wide. More worrisome is the prediction that asteroid Apophis will come very close to Earth on April 13, 2036. Although NASA predicts that it will pass no closer than 18,300 miles above Earth’s surface, Apophis is larger than two football fields. While that’s not big enough to create Hollywood-style global devastation, it could cause significant regional damage, were it ever to strike Earth.
5. Astronauts may go visit one, according to Obama’s new plan for NASA.
In April, President Barack Obama announced the next goal for Americans in space: visiting an asteroid by 2025.
In a panel discussion in April, astrophysicist John Grunsfeld – a former NASA astronaut who flew on five shuttle missions – suggested that one goal might be sending humans to purposely move an asteroid, to nudge the space rock to change its trajectory. Such a feat, he said, would show that humanity could deflect a space rock if one threatened to crash into the planet.
“By going to a near-Earth object, an asteroid, and perhaps even modifying its trajectory slightly, we would demonstrate a hallmark in human history,” Grunsfeld said. “The first time humans showed that we can make better decisions than the dinosaurs made 65 million years ago.”
Source:
http://www.space.com/scienceastronomy/5-reasons-care-about-asteroids-100611.html
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Another Near-Earth Asteroid
Filed under: Asteroid Apophis latest
02 May 2010
Newswise — A near-Earth asteroid named 2005 YU55 – on the list of potentially dangerous asteroids – was observed with the Arecibo Telescope’s planetary radar on April 19, 2010 when it was about 1.5 million miles from the Earth, which is about 6 times the distance to the moon, according to Michael Nolan, director of the Arecibo Observatory.
The Arecibo telescope is located in Arecibo, Puerto Rico, and it is managed by Cornell University on behalf of the National Science Foundation.
Arecibo radar imaging of 2005 YU55 at 25-ft resolution showed that this asteroid is about 400 meters (1,300 feet) in size – about a quarter-mile long – and about twice as large as previously estimated.
On the actual observation at Arecibo, Ellen Howell, a Cornell researcher at Arecibo, was the principal investigator. Other observers include Cornell researcher Patrick Taylor, and Nolan. Jon D. Giorgini of the Jet Propulsion Laboratory (JPL), Pasadena, Calif., conducted the orbital calculations. Lance Benner, Marina Brozovic, both of JPL; Michael Busch of California Institute of Technology, Pasadena; and Chris Magri, University of Maine at Farmington, are collaborators on the project.
This object is on the list of “potentially hazardous asteroids” maintained by the Minor Planet Center, of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.
High-precision radar astrometry reduced orbit uncertainties by 50 percent. This improvement eliminated any possibility of an impact with the Earth for the next 100 years, and it was removed from the “Risk Page” maintained by NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory.
After circling the Sun, 2005 YU55 will next approach the Earth to about 0.8 lunar distances on Nov. 8, 2011. It will pose no impact hazard at that time. Robert McMillan of the Spacewatch asteroid detection program discovered the asteroid on December 28, 2005.
President Barack Obama has proposed that NASA’s “Near Earth Object Observations” program be increased from $3.7 million in 2009 to $20.3 million in 2011. NASA has indicated that it intends to provide support to the Arecibo radar program if that funding remains in the budget. Rep. Jose Serrano, D-N.Y., added $2 million to NASA’s near-Earth object research program in 2010 for support of the Arecibo research work. These funds will offset reduced funding from the National Science Foundation.
The Arecibo Observatory is part of the National Astronomy and Ionosphere Center which is managed by Cornell University under a cooperative agreement with the national Science Foundation.
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