Pan-STARRS discovers its first potentially hazardous asteroid

Pan-STARRS discovers its first potentially hazardous asteroid
This is the Pan-STARRS PS1 Observatory just before sunrise on Haleakala, Maui. Credit: Rob Ratkowski

The Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) PS1 telescope has discovered an asteroid that will come within 4 million miles of Earth in mid-October. The object is about 150 feet in diameter and was discovered in images acquired on September 16, when it was about 20 million miles away.

It is the first "potentially hazardous object" (PHO) to be discovered by the Pan-STARRS survey and has been given the designation "2010 ST3."

"Although this particular object won't hit Earth in the immediate future, its discovery shows that Pan-STARRS is now the most sensitive system dedicated to discovering potentially dangerous asteroids," said Robert Jedicke, a University of Hawaii member of the PS1 Scientific Consortium, who is working on the asteroid data from the telescope. "This object was discovered when it was too far away to be detected by other asteroid surveys," Jedicke noted.

The Harvard-Smithsonian Center for Astrophysics is a major partner in the Consortium.

Most of the largest PHOs have already been catalogued, but scientists suspect that there are many more under a mile across that have not yet been discovered. These could cause devastation on a regional scale if they ever hit our planet. Such impacts are estimated to occur once every few thousand years.

Timothy Spahr, director of the Minor Planet Center (MPC), said, "I congratulate the Pan-STARRS project on this discovery. It is proof that the PS1 telescope, with its Gigapixel Camera and its sophisticated computerized system for detecting moving objects, is capable of finding potentially dangerous objects that no one else has found." The MPC, located in Cambridge, Mass., was established by the International Astronomical Union in 1947 to collect and disseminate positional measurements for asteroids and comets, to confirm their discoveries, and to give them preliminary designations.

Pan-STARRS discovers its first potentially hazardous asteroid
Two images of 2010 ST3 (circled in green) taken by PS1 about 15 minutes apart on the night of Sept. 16 show the asteroid moving against the background field of stars and galaxies. Each image is about 100 arc seconds across. Credit: PS1SC

Pan-STARRS expects to discover tens of thousands of new asteroids every year with sufficient precision to accurately calculate their orbits around the sun. Any sizable object that looks like it may come close to Earth within the next 50 years or so will be labeled "potentially hazardous" and carefully monitored. NASA experts believe that, given several years warning, it should be possible to organize a space mission to deflect any that is discovered to be on a collision course with Earth.

Pan-STARRS has broader goals as well. PS1 and its bigger brother, PS4, which will be operational later in this decade, are expected to discover a million or more asteroids in total, as well as more distant targets such as variable stars, supernovas, and mysterious bursts from galaxies across more than half the universe. PS1 became fully operational in June 2010.

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Sep 27, 2010
I always wondered how expensive would it be to send out a few satellites equipped with radar or similar technology to detect objects around Earth... I suspect the distance to the nearest asteroid might have something to do with it.

Sep 27, 2010
marjon, while I agree that asteroid preimpact discovery is important, why do you think an asteroid impact is more of a threat then global warming? You only have the word of other scientists to go on in both cases since you are clearly not a scientist yourself, so why do you trust the folks at Pan-STARRS but not climatologists? It seems to me your methodology for testing evidence is arbitrary and emotionally motivated, with little reason or logic behind it, but feel free to try and explain yourself if you have a legitimate explanation. I would be delighted to hear it.

Sep 28, 2010
Don't get me wrong, I am not a believer in AGW, I actually have no strong opinion on the matter. I think it's a possibility worth bearing in mind as are most things but I agree it has been exploited politically in ways that are very unjustified and much false information has been spread during the course of the debate.

Sep 28, 2010
For those who are interested, here is an excelent computer animation displaying asteroid discovery progression from 1980 till now, all based on REAL data:

Credits: Scott Manley

Take a drink, open link, choose 720p+ resolution, lean back and relax while watching :) Just make sure not to spill the drink when it gets more intense later on ;-)

Green are non-hazardous, Yellow come near Earth orbit, Red are PHA's (potentialy hazardous, crossing Earth orbit) and Teal are the planets. New additions are temporaly highlighted as White (fading). For more detailed info read the description.

As a side note, the bulk which is present at the end of the video is estimated/believed to include only about 10% of all the PHA's out there, where the rest remains yet undetected. Ouch :)

Sep 28, 2010
... have a list of impending passes. FWIW, there's 1145 currently known PHAs...

Sep 28, 2010
I can visit asteroid impact craters around the world. I can see meteors entering the earth every day and what survives has been collected. Lunar impacts can be observed as well as impacts on other planets.
So you only believe what you can see? What if I pumped radon into your living room, would you be less dead because you can't see it?
Climatologists can't explain why the earth was warmer 1000 years ago.
They have a pretty good idea.
Data implicating CO2 is circumstantial.
Actually it isn't.
Climate peer review is incestuous (Wegman Report)
You mean the discredited wegman report.
and they have chosen to use propaganda and politics instead of data to support their 'consensus' and 'remedies'.
As opposed to FOX news? Marjon, the AGCC proponents have been talking about CO2 based warming since the early 80's. There's a library of evidence, you simply need to read it.

Sep 28, 2010
A 100ft diameter asteroid is a pretty big deal, and would completely annihilate a city.

This object would strike with an energy of 1.94 to 4.36 megatons making a crater ranging from 1.67km wide and 0.33km deep to 1.39km wide and 0.28km deep. This happens on average about every 90 years. Now that's the crater size. The damage caused by the fireball, shockwaves, ejecta, 1000mph winds, conflagration and other secondary explosions would completely vaporize Los Angeles or New York City. The immediate loss of life would depend on exact impact locations but would easily exceed 1 million almost anywhere in the U.S. and could exceed 20 million. The immediate damage and long term economic damage is virtually incalculable.

A 150ft diameter asteroid is 3.375 times as massive as a 100ft diameter asteroid. The energy is between 6.99 and 16 megatons. The crater is between 2.33km wide and 0.66km deep and 1.95km wide and 0.39km deep.

Sep 28, 2010
Since Apophis is potatoe shaped, I used an average diamter of 700ft, or 215 meters:

If Apophis is iron:

714mt to 1606mt explosion
7.41km to 9.15km crater width
0.86km to 0.91km crater depth

If stone:

268mt to 602mt explosion
5.04km to 6.22km crater width
0.76km to 0.81km crater depth

By comparison, the test version of largest nuke ever made was around ~50 megatons while the fully armed version would be around 100 megatons.

So for example, it would probably destroy all life in the entire state of Texas if it hit dead center.

Sep 28, 2010
QC, all of your figures are worthless because you fail to calculate velocity, delta v, and multiple other aspects that would make the problem greater or worse. If anything your estimates are incredibly low.

Sep 28, 2010

For these numbers, I used an impact calculator and assumed velocity 12km/s for lower end and 18km/s for upper end.

Sep 28, 2010

For these numbers, I used an impact calculator and assumed velocity 12km/s for lower end and 18km/s for upper end.

You should simply use the Torino scale calculations instead. Delta V is highly important in accurately determining potential threat. Apophis itself is a 5.6 km/s with max acceleration capable by passing near the earth you'd be lucky to get a bit over 12km/s.

Sep 28, 2010
So for example, it would probably destroy all life in the entire state of Texas if it hit dead center.

Wow, sounds nice. That'd show their state board of education what space thinks of them. But we must also remember that a 100 ft rock won't be 100ft after entering the atmosphere. I'm not sure what the size reduction would be, but it would get smaller. That alone changes our perception of which objects are really dangerous.

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