Another asteroid to miss us by a hair

March 31, 2009 17:54 by scibuff

Today at 23:58 UT asteroid labeled as 2009 FP will pass the Earth at a distance of about 0.003 AU which roughly represents 1.2 Lunar Distances (LD). The comfortable separation of 445,000 km is not a “hair” per se, nevertheless it is quite close by space standards.

Orbit Diagram of 2009 FP - Source: NASA JPL

Orbit Diagram of 2009 FP - Source: NASA JPL

This Near Earth Object (NEO) was discovered at 05:46 UT on March 29 by Mount Lemmon Survey (MLS) in Arizona, one of the three facilities of the Catalina Sky Survey. The probability of impacting the Earth is only 1 in 133,000. The asteroid has a diameter of approximately 10 meters and poses no risk to anyone as it would certainly break up in the Earth’s atmosphere and rain down only a few small fragments (meteorites).

Astronomers have been conducting surveys to locate objects whose orbits bring them to close proximity with the Earth for decades. However, automatization techniques first introduced by LINEAR program greatly increased the numbers of discovered asteroid in the last ten year. LINEAR alone is responsible for the discovery of more than 220,000 new objects out of which more than 2,000 classify and NEO’s (NEO is a Solar System object with perihelion distance less than 1.3 AU).

NEO Chart - Source: NASA JPL

NEO Chart - Source: NASA JPL

It might seem that Earth’s neighborhood got filled fill space junk suddenly as news of fireballs have filled internet blogs and even TV news over the past 6 months. Fortunately, it is far more likely that general public and media simply pay more attention to these events. Additionally, astronomers are becoming better at detecting even the smallest objects days before they pass the Perigee of their orbits. Bad Astronomer offers a great explanation for this “puzzling” phenomenon:

I think it’s a mix of coincidence — there may be a few more than usual, but it’s not like these things have published schedules; sometimes there are more and sometimes fewer — together with people being more aware of them because they’ve been in the news lately. It’s like buying a car and suddenly seeing it everywhere when you drive. We notice what we’re primed to notice.

Below is a short list of notable objects that crossed path with Earth in the past six month:

On October 6, 2008 Richard A. Kowalski of the Catalina Sky Survey discovered a meteoroid, later labeled as  2008 TC3, that entered Earth’s atmosphere only 20 hours later, at 02:46 UT on October 7, 2008 over Sudan. There was great excitement in NEO community as it was the first time a prediction was issued about an object entering Earth’s atmosphere. Consequent observations led to discovery of several fragments of the original piece of rock that measured about 5 meters in diameter. Here is an animation of what an observer on the asteroid would see in the last hours before the atmospheric entry.

A very bright fireball lit up the skies in Alberta and Saskatchewan, Canada around 22:30 UT on Thursday, November 20, 2008.

Only two months later this footage from Sweden captures a spectacular meteor that entered Earth’s atmosphere on January 17, 2009.

It is quite rare to see a meteor during daylight as most meteors are too faint to be noticed. One of the exceptions is the great fireball of 1972 which was the first Earth-grazing object ever observed.

Earth-grazing fireballs are caused by a meteoroid that enters the atmosphere but overcomes the Earth’s gravity and exists back into outer space. Only four grazers have been scientifically observed.

A very bright daylight meteor was seen over Texas on February 15, 2009. Only a few days later, two astronomers claimed to have found meteorite debris.

On March 2, 2008 at 13:45UT we had the first close miss of March when Asteroid 2009 DD45, discovered only a few days before, reached the perigee distance of 72,000 km.

Orbit Diagram of 2009 DD45 - Source: NASA JPL

Orbit Diagram of 2009 DD45 - Source: NASA JPL

Two weeks later, on March 18 at 12:17 UT another interplanetary rock 15 meters across, 2009 FH, flew by reaching minimal geocentric distance of 79,000 km. Both of these objects passed us at only twice the altitude of geostationary satellites.

Orbit Diagram of 2009 FH - Source: NASA JPL

Orbit Diagram of 2009 FH - Source: NASA JPL

If this feels like the Universe is out there to get us … well … that’s right. We know with 100% certainty that it will eventually succeed.