New Count of Potentially Hazardous Asteroids

A New Count of Potentially Hazardous Asteroids

May 16, 2012:  Observations from NASA's Wide-field Infrared Survey Explorer (WISE) have led to the best assessment yet of our solar system's population of potentially hazardous asteroids. Also known as "PHAs," these asteroids have orbits that come within five million miles (about eight million kilometers) of Earth, and they are big enough to survive passing through Earth's atmosphere and cause damage on a regional, or greater, scale.

The asteroid-hunting portion of the WISE mission, called NEOWISE, sampled 107 PHAs to make predictions about the population as a whole. Findings indicate there are roughly 4,700 PHAs, plus or minus 1,500, with diameters larger than 330 feet (about 100 meters). So far, an estimated 20 to 30 percent of these objects have been found.

In this simulated view of the near-Earth asteroid population, potentially hazardous asteroids (PHAs) are denoted in orange. Less dangerous near-Earth asteroids are blue. Earth's orbit is green. [more]

While previous estimates of PHAs predicted similar numbers, they were rough approximations. NEOWISE has generated a more credible estimate of the objects' total numbers and sizes. Because the WISE space telescope detected the infrared light, or heat, of asteroids, it was able to pick up both light and dark objects, resulting in a more representative look at the entire population.

"The NEOWISE analysis shows us we've made a good start at finding those objects that truly represent an impact hazard to Earth," said Lindley Johnson, program executive for the Near-Earth Object Observation Program at NASA Headquarters. "But we've many more to find, and it will take a concerted effort during the next couple of decades to find all of them that could do serious damage or be a mission destination in the future."

This orbit diagram illustrates the difference between a PHA and less hazardous near-Earth asteroids (NEA). [more]

The new analysis suggests that about twice as many PHAs as previously thought reside in low-inclination orbits, which are roughly aligned with the plane of Earth's orbit.

"Our team was surprised to find the overabundance of low-inclination PHAs," said Amy Mainzer, NEOWISE principal investigator, at NASA's Jet Propulsion Laboratory. "Because they will tend to make more close approaches to Earth, these targets can provide the best opportunities for the next generation of human and robotic exploration."

The NEOWISE analysis suggests a possible origin for the low-inclinaton PHAs: Many of them could have originated from a collision between two asteroids in the main belt lying between Mars and Jupiter. A larger body with a low-inclination orbit may have broken up in the main belt, causing some of the fragments to drift into orbits closer to Earth and eventually become PHAs.

The lower-inclination PHAs appear to be somewhat brighter and smaller than other near-Earth asteroids. The discovery that PHAs tend to be bright says something about their composition; they are more likely to be either stony, like granite, or metallic. This type of information is important in assessing the space rocks' potential hazards to Earth. The composition of the bodies would affect how quickly they might burn up in our atmosphere if an encounter were to take place.

"The NEOWISE project, which wasn't originally planned as part of WISE, has turned out to be a huge bonus," said Mainzer.  "Everything we can learn about these objects helps us understand their origins and fate."

The NEOWISE results have been accepted for publication in the Astrophysical Journal.

SOURCE: http://science.nasa.gov/science-news/science-at-nasa/2012/16may_pha/

On May 17, 2012 there were 1287 potentially hazardous asteroids.

Recent & Upcoming Earth-asteroid encounters:

Asteroid	Date(UT)	Miss Distance	Mag.	Size
2012 JU	May 13	0.5 LD	--	10 m
2012 KA	May 17	0.6 LD	--	8 m
2010 KK37	May 19	2.3 LD	--	31 m
4183 Cuno	May 20	47.4 LD	--	5.7 km
2012 JV11	May 22	6.7 LD	--	69 m
2002 VX94	May 26	72.8 LD	--	1.1 km
2002 AC	Jun 16	62.2 LD	--	1.2 km
1999 BJ8	Jun 16	68.8 LD	--	1.1 km
2005 GO21	Jun 21	17.1 LD	--	2.2 km
2003 KU2	Jul 15	40.3 LD	--	1.3 km
2004 EW9	Jul 16	46.8 LD	--	2.1 km
2002 AM31	Jul 22	13.7 LD	--	1.0 km
37655 Illapa	Aug 12	37 LD	--	1.2 km

Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.
SOURCE:http://spaceweather.com/

Asteroid Named 2012 KA Blazing Earth Near You May 17, 2012

Asteroid 2012 KA to Buzz Earth on May 17

by NANCY ATKINSON on MAY 17, 2012

Orbit diagram of asteroid 2012 KA from JPL's Small Body Database website.
On the heels of a bus-sized asteroid that passed harmlessly between Earth and the orbit of the Moon on May 13, another asteroid between 4.5 and 10 meters (14-33 feet) wide will buzz by at about the same distance on May 17, 2012. Asteroid 2012 KA was discovered just today (May 16), and is projected to make its closest approach about 0.0015 AU, or 224,397 kilometers (134,933 miles, .6 lunar distances) from Earth’s surface at 19:43 UTC on Thursday. The asteroid was discovered by the Mt. Lemmon Observatory, and at the time of this writing, is the only observatory that has made any observations. Therefore JPL lists the uncertainty of the orbit as fairly high (9 out of a 1 to 10 scale) but orbital projections from JPL’s Small Body Database website confirms there is no chance this asteroid would hit Earth. However, most stony meteoroids up to a diameter of about 10-meters are destroyed in thermal explosions by plummeting through Earth’s atmosphere.

source: http://www.universetoday.com/95202/asteroid-2012-ka-to-buzz-earth-on-may-17/

On May 17, 2012 there were 1287 potentially hazardous asteroids.

Recent & Upcoming Earth-asteroid encounters:

Asteroid	Date(UT)	Miss Distance	Mag.	Size
2012 JU	May 13	0.5 LD	--	10 m
2012 KA	May 17	0.6 LD	--	8 m
2010 KK37	May 19	2.3 LD	--	31 m
4183 Cuno	May 20	47.4 LD	--	5.7 km
2012 JV11	May 22	6.7 LD	--	69 m
2002 VX94	May 26	72.8 LD	--	1.1 km
2002 AC	Jun 16	62.2 LD	--	1.2 km
1999 BJ8	Jun 16	68.8 LD	--	1.1 km
2005 GO21	Jun 21	17.1 LD	--	2.2 km
2003 KU2	Jul 15	40.3 LD	--	1.3 km
2004 EW9	Jul 16	46.8 LD	--	2.1 km
2002 AM31	Jul 22	13.7 LD	--	1.0 km
37655 Illapa	Aug 12	37 LD	--	1.2 km

Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.

Source: http://spaceweather.com

Here is the conversion from meters to feet 8 m = 26.2467 '

Some interesting reports from the American Meteor Society...

http://www.amsmeteors.org/fireball2/public.php?start_date=2012-05-13&end_date=2012-05-31&state=&event_id=&submit=Find+Reports

2012-05-13 Wichita, KS  

I like watching satellites passing over head at Night. I was out around 4AM, looked up and saw a small green glow burn out directly overhead (NW to SE direction). A few minutes later I went out again, when I turned west I saw the much larger object off in the distance falling near vertical, Green at first then Orange and lighting up low clouds. Because I believed it was space Junk I didn't think much about it. It is not unusual in Kansas to see a Green glowing object fall back to earth. I checked the web and it brought me to this site. It was falling steeply vertical exploded very low to the Horizon, what I saw was low clouds light up with a orange glow. I thought it was space Junk and didn't attach that much importance to it. Several minutes earlier what appeared a small piece of copper (Green ) passed directly over me burning out like a shooting star. I had just written a piece on changing the economic system and regarded these events as signs acknowledging my work and place in the future. Because it was space junk I wasn't particularly impressed. Happened at night, was Green then turned Orange as it passed through and lit up low clouds.

2012-05-13  Wichita, KS

The greenish glow was unusual. The orange was very distinct in the explosion, which leads me to suspect it may have been space junk of some kind. The near vertical angle from my perspective was also worth noting. I'd wager it may have left debris, whatever it was some where south west of Wichita Kansas, with in 100 miles, and in a small area. The explosion was quite large as well, with arcing debris from the epicenter, very spectacular and I feel fortunate to have witnessed it being an amateur astronomer. The biggest and brightest I've ever seen. I'm currently searching for an all sky came here in Kansas to get a better look. I don't believe Lake Afton Observatory has one, but I will check. The other individual who saw it got a better view, and I will prompt him to make a report as well so we can better correlate our data. Just before the explosion, it brightened, then exploded into what seemed many orange pieces that spread out much like a flare in several directions, the green glow had gone, and it turned all orange. Not really a bright white flash as others I had witnessed, more of a yellowish flash. The greenish glow was unusual. The orange was very distinct in the explosion, which leads me to suspect it may have been space junk of some kind. The near vertical angle from my perspective was also worth noting. I'd wager it may have left debris, whatever it was some where south west of Wichita Kansas, with in 100 miles, and in a small area. The explosion was quite large as well, with arcing debris from the epicenter, very spectacular and I feel fortunate to have witnessed it being an amateur astronomer. The biggest and brightest I've ever seen. I'm currently searching for an all sky came here in Kansas to get a better look. I don't believe Lake Afton Observatory has one, but I will check. The other individual who saw it got a better view, and I will prompt him to make a report as well so we can better correlate our data.

2012-05-13 Doniphan, MO

I do not think it was a meteor but I am trying to find out what it was. It was a bright orange/red that fluctuated in intensity slightly, like a flame flickering. There was no wind so it was not anything floating with the wind. At first I thought it was a spotlight for incoming medivac helicopter, but as it passed the intensity stayed the same. It was not a spotlight. It did not blink like a plane and was brighter than a planes lights. It made no noise. The speed was similar to satelites I have seen pass, but it was much brighter. It faded and disappeared, like I have seen the ISS do as it passes into the Earths shadow. I checked the path of the ISS, wrong location in the sky and wrong direction of travel. I did not know where else to report this.

2012-05-13  Kenilworth, IL

I would love to know if these were indeed meteors. There were other cars who pulled aside to look at them. I saw 6 gold balls moving across the sky at a low altitude. The last ones were lit up very brightly on the inside and I don't remember the first ones as they had passed by before they were overhead.. They were moving in a line from east to west and disappeared as they moved west. It was dark and I saw no trail. I watched them for several minutes. A very extraordinary experience and I had no idea what I was seeing. The last one was about the size of a hot air balloon. I called the police dept. the next day and they told me it sounded like a meteor this man had seen at another time. It was amazing..

2012-05-13  SLC, UT

Strangely my friend Audrey and I saw a very simila r one about 4 or 5 years ago. It was exciting to see on as big as this again and with the same person! I love the chaos! ;-) The fireball traveled behind some trees to the south but was very strong still. There were small fragments trailing behind a much larger ball. Glowing train with fragments. Did not see the fireball go out as it passed behind trees and was very strong still at that point.

2012-05-14  Chesterton, IN

This was not a fire ball. I was Much bigger. At 11 :30pm central time I was sitting in my deck and my husband noticed something overhead. It was something I have never seen before. It was not a shooting star or a fireball but a very large object that traveled from south to north towards Lake Michigan. It was grey blue in color and had a halo and small tail. We watched it for 10 seconds and if I were to guess I would say it were an asteroid skimming our upper atmosphere. I was stunned at the size of it. Blue gray train not very long.

2012-05-14  bozeman, MT

I have not ever seen anything like that. Very brig ht! Very bright. I would have rated it as bright as the sun, but did not see the object long enough to make that call. I have not ever seen anything like that. Very bright! This object looked to be the size of an SUV. It came in very fast and I only caught the last part of it, but it was that large to be even reporting it. Very bright orange train wiht a smoke clowd that last a few seconds after the trail.This object looked like something was going to be left after the burn in. I would say, in the 4 corners area of Montana is where it may have landed.

2012-05-15  Downingtown, PA

I just saw this 20 minutes ago in Pennsylvania- th ere were about seven all in a perfectly straight row, flying against the wind. They just disappeared into a cloud. They were moving only slightly slower than a plane, but there was no sound at all. No train- It was just a line of glowing orange orbs (approximately 6-7), about a quarter of a mile apart from each other, moving in a perfectly straight line against the wind.

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."

SOURCE: KSL.COM

__________________________________________________________

Dwayne Brown
Headquarters, Washington
202-358-1726
dwayne.c.brown@nasa.gov


Nancy Neal Jones
Goddard Space Flight Center, Greenbelt, Md.
301-286-0039
nancy.n.jones@nasa.gov 

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: 

http://www.nasa.gov

For more information on Target Asteroids! and OSIRIS-REx, visit: 

http://osiris-rex.lpl.arizona.edu

- end -

SOURCE: NASA

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.

SOURCE: KVOA.COM

Impact of large asteroid may cause disruption of Earth ozonosphere

 October 28th, 2010 |  Author: Leonid Elenin

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.


SOURCE:  SPACE OBS.ORG LEONID ELENIN

New observations of Apophis

 March 18th, 2011 |  Author: Leonid Elenin

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.


SOURCE:  SPACE OBS.ORG LEONID ELENIN