You, too, can be an asteroid hunter — thanks to a citizen-science project launched by the University of Arizona’s Lunar and Planetary Laboratory. And you might even get a scientific citation.
The project is enlisting human spotters to verify potential detections of space rocks moving through the field of view of the Catalina Sky Survey’s telescopes. The NASA-funded survey is charged with keeping track of more than a million asteroids, with a principal goal of identifying near-Earth objects that could pose a risk to our planet.
More than 14,400 near-Earth objects, or NEOs, have been discovered by the Catalina Sky Survey during the past 30 years, including 1,200 that were identified just in the past year. That adds up to nearly half of the known NEO population.
The problem is, astronomers know there are still lots of unknown asteroids out there — too many for them to spot without an assist from amateurs. “We take so many images of the sky each night that we cannot possibly look through all of our potential real asteroids,” Carson Fuls, a science engineering specialist for the Catalina Sky Survey, said in a NASA news release. That’s where the Daily Minor Planet can make a difference.
Humanity is getting better a planetary defense. At least from external threats from outer space. As long as they’re just dumb rocks that follow the laws of physics. And a group of extraordinary humans proved it last week when the planetary defense community jumped into action to accurately track and predict exactly where a relatively small meteor would fall on November 19th.
It’s a shooting gallery out there. The spattered face of Earth’s Moon and large impact sites such as Meteor Crater outside of Flagstaff, Arizona remind us that we still inhabit a dangerous neck of the solar neighborhood. But despite the inevitable cries proclaiming the “End of the World of the Week” this coming weekend, humanity can breathe a collective sigh of relief next Wednesday on April 19th, when asteroid 2014 JO25 passes safely by the Earth.
To be sure, lots of smaller space rocks pass by the Earth closer than the Moon (that’s an average of 240,000 miles distant) on a monthly basis. Take for example 4-meter asteroid 2017 GM, which passed just 16,000 kilometers distant on April 4th. What makes 2014 JO25 special is its size: measurements from NASA’s NEOWISE mission suggest that 2014 JO25 is about 2,000 feet (650 meters) along its longest axis, about twice the length of a Nimitz-class aircraft carrier. 2014 JO25 is passing 1.1 million miles (1.8 million kilometers) or 4.6 times the Earth-Moon distance on Wednesday, the closest large asteroid pass since 5-km Toutatis in September, 2004. The next predicted large asteroid pass near Earth is 1999 AN10, set to pass 1 LD (lunar distance) from the Earth in 2027.
This is also the closest passage of 2014 JO25 near the Earth for a 900 year span.
Discovered on May 5th, 2014 by the Catalina Sky survey, asteroid 2014 JO25 orbits the Sun once every three years, taking it from a perihelion of 0.237 AU (interior to Mercury’s orbit) out to an aphelion of 3.9 distant in the asteroid belt, interior to Jupiter’s orbit.
Finding 2014 JO25 at its Closest Approach
With an estimated albedo (surface brightness) about twice that the lunar surface, 2014 JO25 will reach magnitude +10 to +11 on closest approach on Wednesday. Currently low in the dawn sky in the Square of Pegasus asterism, asteroid 2014 JO25 passed perihelion sunward as seen from the Earth at 1.015 Astronomical Units (AU) distant on March 11th. At its closest to the Earth on April 19th at 12:24 Universal Time (UT)/6:24 AM EDT, asteroid 2014 JO25 will skim the jagged Draco-Ursa Minor border below the bowl of the Little Dipper, moving at a whopping three degrees per hour. Sitting just 25 degrees from the north celestial pole on closest approach, catching sight of 2014 JO25 at favors western North America and northeastern Asia, though the eastern half of North America and Europe have a shot at the asteroid a few hours prior to closest approach in the early morning hours of April 19th. North American viewers get another shot at catching the fleeting asteroid later the same evening 13 hours after closest approach as the asteroid sails through the galaxy-rich constellation Coma Berenices.
At +11th magnitude, you’ll need a telescope of at least 6” aperture or larger and a good star chart to nab 2014 JO25 as it glides against the starry background. Fellow Universe Today contributor Bob King has some great star charts of the pass over at Sky & Telescope. The Moon will be at Last Quarter phase on the morning of the 19th, providing moderate light pollution.
And if you’re out hunting for asteroids on the coming mornings, there are currently two bright binocular comets in the dawn sky to keep you company: Comet C/2017 E4 Lovejoy in the constellation Andromeda and Comet C/2015 ER61 PanSTARRS in Aquarius. Both are currently performing above expectations at about magnitude +7.
“What if” an asteroid the size of 2014 JO25 hit the Earth? Well, the Chelyabinsk meteor was an estimated 20 meters in size; the impactor that formed Meteor Crater in Arizona was about 50 meters in diameter. The Chicxulub event off the Yucatan peninsula 66 million years ago was an estimated 10 kilometer-sized impactor well over ten orders of magnitude bigger than 2014 JO25. While the impact of a 600 meter asteroid would be a noteworthy event and a bad day locally, it would pale in comparison to an extinction level event.
All something to consider, as you watch the faint dot of asteroid 2014 JO25 pass harmlessly by the Earth and through the news cycle for the coming week.
No one’s 100% certain what WT1190F is — asteroid or rocket stage — but we are certain it will light up like a Roman candle when it re-enters Earth’s atmosphere around 6:20 Universal Time (12:20 a.m. CST) tomorrow morning Nov. 13.
Animation by Jost Jahn of WT1190F’s final hours as it races across the sky coming down off the coast of Sri Lanka
As described in an earlier story at Universe Today, an object discovered by the Catalina Sky Survey on Oct 3rd and temporarily designated WT1190F is expected to burn up about 60 miles (100 km) off the southern coast of Sri Lanka overnight. The same team observed it twice in 2013. Based upon the evolution of its orbit, astronomers determined that the object is only about six feet (2-meters) across with a very low density, making it a good fit for a defunct rocket booster, possibly one used to launch either one of the Apollo spacecraft or the Chinese Chang’e 3 lander to the Moon.
Additional observations of WT1190F have been made in the past few days confirming its re-entry later tonight. Checking the latest predictions on Bill Gray of Project Pluto’s page, the object will likely be visible from Europe about an hour before “touchdown”. To say it will be moving quickly across the sky is an understatement. Try about 3 arc minutes per second or 3° a minute! Very tricky to find and track something moving that fast.
58 minutes later, in the minute of time from 6:18 to 6:19 UT, WT1190F will move one full hour of right ascension and plummet 34° in declination while brightening from magnitude +8 to +4.5. If you’d like to attempt to find and follow the object, head over to JPL’s Horizons site for the latest ephemerides and orbital elements. At the site, make sure that WT1190F is in the Target Body line. If not, click Change and search for WT1190F in the Target Body field at the bottom of the window.
You’ll find updates at Bill Gray’s site. According to the most recent positions, the object will pass almost exactly in front of the Sun shortly before plunging into the ocean. Sri Lanka’s capital, Colombo, is expected to get the best views.
Because the mystery object’s arrival has been fairly well publicized, I hope to update you with a full report and photos first thing tomorrow morning. Like many of you, I wish I could see the show.
Get ready for a man-made fireball. A object discovered by the Catalina Sky Survey on Oct 3rd temporarily designated WT1190F is predicted to impact the Earth about 60 miles (100 km) off the southern coast of Sri Lanka around 6:20 Universal Time (12:20 a.m CST) on November 13.
The object orbits Earth with a period of about three weeks. Because it was also observed twice in 2013 by the same survey team, astronomers have the data they need to model its orbit and trajectory, and as far anyone can tell, it’s likely man-made.
Solar radiation pressure, the physical “push” exerted by photons of sunlight, is proportional to a space object’s area-to-mass ratio. Small, lightweight objects get pushed around more easily than heavier, denser ones. Taking that factor into account in examining WT1190F’s motion over two years, the survey team has indirectly measured WT1190F’s density at about 10% that of water. This is too low to be a typical asteroid made of rock, but a good fit with a hollow shell, possibly the upper stage of a rocket.
It’s also quite small, at most only about six feet or a couple of meters in diameter. Most or all of it is likely to burn up upon re-entry, creating a spectacular show for anyone near the scene. During the next week and a half, the European Space Agency’s NEO (Near-Earth Object) Coordination Centeris organizing observing campaigns to collect as much data as possible on the object, according to a posting on their website. The agency has two goals: to better understand satellite re-entries from high orbits and to use the opportunity to test our readiness for a possible future event involving a real asteroid. The latter happened once before when 2008 TC3(a real asteroid) was spotted on October 6, 2008 and predicted to strike Earth the very next day. Incredibly, it did and peppered the Sudan with meteorites that were later recovered.
Assuming WT1190F is artificial, its trans-lunar orbit (orbit that carries it beyond the Moon) hints at several possibilities. Third stages from the Saturn-V rockets that launched the Apollo missions to the Moon are still out there. It could also be a stage from one of the old Russian or more recent Chinese lunar missions. Even rockets used to give interplanetary probes a final push are game.
Case in point. What was thought initially to be a new asteroid discovered by amateur astronomer Bill Yeung on September 3, 2002 proved a much better fit with an Apollo 12 S-IVB (third) stage after University of Arizona astronomers found that spectra taken of the object strongly correlated with absorption features seen in a combination of man-made materials including white paint, black paint, and aluminum, all consistent with Saturn V rockets.
Apollo 13’s booster was the first deliberately crashed into the Moon, where it blew out it a crisp, 98-foot-wide (30-meter) crater. Why do such a crazy thing? What better way to test the seismometers left by the Apollo 12 crew? All subsequent boosters ended their lives similarly in the name of seismography. Third stages from earlier missions — Apollos 8, 10 and 11 — entered orbit around the Sun, while Apollo 12, which is orbiting Earth, briefly masqueraded as asteroid J002E3.
Bill Gray at Project Pluto has a page up about the November 13 impact of WT1190F with more information. Satellite and asteroid watchers are hoping to track the object before and right up until it burns up in the atmosphere. Currently, it’s extremely faint and moving eastward in Orion. You can click HERE for an ephemeris giving its position at the JPL Horizons site. How exciting if we could see whatever’s coming down before its demise on Friday the 13th!
Itching for some cometary action? After a fine winter’s performance from Comet C/2014 Q2 Lovejoy, 2015 has seen a dearth of good northern hemisphere comets. That’s about to change, however, as Comet C/2013 US10 Catalina joins the planetary lineup currently gracing the dawn sky in early November. Currently located in the constellation Centaurus and shining at magnitude +6, Comet US10 Catalina has already put on a fine show for southern hemisphere observers over the last few months during Act I.
Currently buried in the dusk sky, Comet US10 Catalina is bashful right now, as it shares nearly the same right ascension with the Sun over the next few weeks, passing just eight degrees from our nearest star as seen from our Earthly vantage point on November 7th — and perhaps passing juuusst inside of the field of view for SOHO’s LASCO C3 camera — and into the dawn sky.
The hunt is on come early November, as Comet US 10 Catalina vaults into the dawn sky. From 30 degrees north latitude here in Central Florida, the comet breaks 10 degrees elevation an hour prior to local sunrise right around November 20th. This should see the comet peaking in brightness right around magnitude +5 near perihelion the same week on November 16th.
The angle of the comet’s orbit is favorable for northern hemisphere viewers in mid-November, as viewers start getting good looks in the early morning from latitude 30 degrees northward and the comet gains about a degree of elevation per day. This will bring it up out of the murk of twilight and into binocular view.
Mark your calendar for the morning of December 7th, as the crescent Moon, Venus and a (hopefully!) +5 magnitude comet US10 Catalina will all fit within a five degree circle.
Here are some key dates with celestial destiny for Comet US10 Catalina for the remainder of 2015:
20-Crosses into the constellation Hydra.
2-Crosses into the constellation Libra.
16-Crosses into the constellation Virgo.
16-Reaches perihelion at 0.823 AU (127.6 million kilometers) from Sun.
26-Crosses the ecliptic plane northward.
27-Passes less than one degree from the +4.5 magnitude star Lambda Virginis.
7-Fits inside a five degree circle with Venus and the waning crescent Moon.
8-Passes less than one degree from the +4 magnitude star Syrma (Iota Virginis).
17-Crosses the celestial equator northward.
24-Crosses into the constellation Boötes.
In January, Comet US10 Catalina starts the New Year passing less than a degree from the -0.05 magnitude star Arcturus. From there, the comet may drop below +6 magnitude and naked eye visibility by mid-month, just prior to its closest approach to the Earth at 0.725 AU (112.3 million kilometers) on January 17th. By February 1st, the comet may drop below +10th magnitude and binocular visibility, into the sole visual domain of large light bucket telescopes under dark skies.
Or not. Comets and predictions of comet brightness are always notoriously fickle, and rely mainly on just how the comet performs near perihelion. Then there’s twilight extinction to contend with, and the fact that the precious magnitude of the comet is diffused over its extended surface area, often causing the comet to appear fainter visually than the quoted magnitude.
But do not despair. Comets frequently under-perform pre-perihelion passage, only to put on brilliant shows after. Astronomers discovered Comet US10 Catalina on Halloween 2013 from the Catalina Sky Survey based just outside of Tucson, Arizona. On a several million year orbit, all indications are that Comet US10 Catalina is a dynamically new Oort Cloud visitor and will probably get ejected from the solar system after this all-too brief fling with the Sun. Its max velocity at perihelion will be 46.4 kilometers per second, three times faster than the New Horizons spacecraft currently on an escape trajectory out of the solar system.
The odd ‘US10’ designation comes from the comet’s initial identification as an asteroidal object, later upgraded to cometary status. The comet’s high orbital inclination of 149 degrees assured two separate showings, as the comet approached the Sun as seen from the Earth’s southern hemisphere, only to then vault up over the northern hemisphere post-perihelion. As is often the case, the comet was closest to the Sun at exactly the wrong time: had perihelion occurred around May, the comet would’ve passed the Earth just 0.17 AU (15.8 million miles or 26.3 million kilometers) distant! That might’ve placed the comet in the negative magnitudes and perhaps earned it the title of ‘the Great Comet of 2015…’
But such was not to be.
Ah, but the next ‘big one’ could come at any time. In 2016, we’re tracking comet C/2013 X1 PanSTARRS, which will ‘perhaps’ become a fine binocular comet next summer…
More to come. Perhaps we’ll draft up an Act III for US10 Catalina in early January if it’s a top performer.
The self-professed “Pluto Killer” is at it again. Dr. Michael Brown is now reminiscing about the good old days when one could scour through sky survey data and discover big bright objects in the Kuiper Belt. In his latest research paper, Brown and his team have concluded that those days are over.
Ten years ago, Brown discovered what is now known as the biggest Kuiper Belt object – Eris. Brown’s team found others that rivaled Pluto in size and altogether, these discoveries led to the demotion of Pluto to dwarf planet. Now, using yet another sky survey data set but with new computer software, Brown says that its time to move on.
Like the famous Bugs Bunny cartoon, its no longer Rabbit Season or Duck Season and as Bugs exclaims to Elmer Fudd, there is no more bullets. Analyzing seven years worth of data, Brown and his team has concluded we are fresh out of Pluto or Charon-sized objects to be discovered in the Kuiper Belt. But for Dr. Brown, perhaps it now might be Oort Cloud season.
His latest paper, A Serendipitous All Sky Survey For Bright Objects In The Outer Solar System, in pre-print, describes the completion of analysis of two past sky surveys covering the northern and southern hemisphere down to 20 degrees in Galactic latitude. Using revised computer software, his team scoured through the data sets from the Catalina Sky Survey (CSS) and the Siding Spring Survey (SSS). The surveys are called “fast cadence surveys” and they primarily search for asteroids near Earth and out to the asteroid belt. Instead Brown’s team used the data to look at image frames spaced days and months apart.
Update: In a Twitter communique, Dr. Brown stated, “I would say we’re out of BRIGHT ones, not big ones. Could be big ones lurking far away!” His latest work involved a southern sky survey (SSS) to about magnitude 19 and the northern survey (CSS) to 21. Low albedo (dark) and more distant KBOs might be lurking beyond the detectability of these surveys that are in the range of Charon to Pluto in size.
Objects at Kuiper Belt distances move very slowly. For example, Pluto orbits the Sun at about 17,000 km/hr (11,000 mph), taking 250 years to complete one orbit. These are speeds that are insufficient to maintain ven a low-Earth orbit. Comparing two image frames spaced just hours apart will find nearby asteroids moving relative to the star fields but not Kuiper belt objects. So using image frames spaced days, weeks or even months apart, they searched again. Their conclusion is that all the big Kuiper belt objects have been found.
The only possibility of finding another large KBO lies in a search of the galactic plane which is difficult due to the density of Milky Way’s stars in the field of view. The vast number of small bodies in the Kuiper belt and Oort Cloud lends itself readily to statistical analysis. Brown states that there is a 32% chance of finding another Pluto-sized object hiding among the stars of the Milky Way.
Dr. Brown also released a blog story in celebration of the discovery of the largest of the Kuiper Belt objects, Eris, ten years ago last week. Ten years of Eris, reminisces about the great slew of small body discoveries by Dr. Brown, Dr. Chad Trujillo of Gemini Observatory and Dr. David Rabinowitz of Yale Observatory.
Brown encourages others to take up this final search right in the galactic plane but apparently his own intentions are to move on. What remains to be seen — that is, to be discovered — are hundreds of large “small” bodies residing in the much larger region of the Oort Cloud. These objects are distributed more uniformly throughout the whole spherical region that the Cloud defines around the Sun.
Furthermore, Dr. Brown maintains that there is a good likelihood that a Mars or Earth-sized object exists in the Oort Cloud.
Small bodies within our Solar System along with exo-planets are perhaps the hottest topics and focuses of study in Planetary Science at the moment. Many graduate students and seasoned researchers alike are gravitating to their study. There are certainly many smaller Kuiper belt objects remaining to be found but more importantly, a better understanding of their makeup and origin are yet to be revealed.
Presently, the Dawn spacecraft is making final approach to the dwarf planet Ceres in the Asteroid belt. The first close up images of Ceres are only a few days away as Dawn is now just a couple of 100 thousand miles away approaching at a modest speed. And much farther from our home planet, scientists led by Dr. Alan Stern of SWRI are on final approach to the dwarf planet Pluto with their space probe, New Horizons. The Pluto system is now touted as a binary dwarf planet. Pluto and its moon Charon orbit a common point (barycenter) in space that lies between Pluto and Charon.
So Dr. Brown and team exits stage left. No more dwarf planets – at least not soon and not in the Kuiper belt. Will that upstage what is being called the year of the Dwarf Planet?
But next up for close inspection for the first time are Ceres, Pluto and Charon. It should be a great year.
Guess who’s dropping by for a quick visit this weekend? On Sunday, a 60-foot-wide (20-meters) asteroid named 2014 RC will skim just 25,000 miles (40,000 km) from Earth. That’s within spitting distance of all those geosynchronous communication and weather satellites orbiting at 22,300 miles.
Size-wise, this one’s similar to the Chelyabinsk meteorite that exploded over Russia’s Ural Mountains region in February 2013. But it’s a lot less scary. 2014 RC will cleanly miss Earth this time around, and although it’s expected back in the future, no threatening passes have been identified. Whew!
NEOs or Near Earth Asteroids are defined as space rocks that come within about 28 million miles of Earth’s orbit. Nearly once a month astronomers discover an Earth-crossing asteroid that passes within the moon’s orbit. In spite of hype and hoopla, none has threatened the planet. As of February 2014, we know of 10,619 near-Earth asteroids. It’s estimated that 93% of all NEOs larger than 1 km have been discovered but 99% of the estimated 1 million NEOs 100 feet (30-meters) still remain at large.
No surprise then that new ones pop up routinely in sky surveys. Take this past Sunday night for example, when the Catalina Sky Survey nabbed 2014 RA, a 20-foot (6-meter) space rock that whistled past Earth that evening at 33,500 miles (54,000 km). It’s now long gone.
2014 RC was picked up on or about September 1-2 by both the Catalina Sky Survey and Pan-STARRS 1 survey telescope atop Mt. Haleakala in Maui. The details are still being worked out as to which group will take final discovery credit. Based on current calculations, 2014 RC will pass closest to Earth around 2:15 p.m. EDT (18:15 UT) on Sunday, September 7th. When nearest, the asteroid is expected to brighten to magnitude +11.5 – too dim for naked eye observing but visible with a good map in 6-inch and larger telescopes.
Seeing it will take careful planning. Unlike a star or planet, this space rock will be faint and barreling across the sky at a high rate of speed. Discovered at magnitude +19, 2014 RC will brighten to magnitude +14 during the early morning hours of September 7th. Even experienced amateurs with beefy telescopes will find it a challenging object in southern Aquarius both because of low altitude and the unwelcome presence of a nearly full moon.
64-frame movie showing Toutatis tumbling through space only 4.3 million miles from Earth on Dec. 12-13. Credit: NASA/Goldstone radar
Closest approach happens in daylight for North and South America , but southern hemisphere observers might spot it with a 6-inch scope as a magnitude +11.5 “star” zipping across the constellations Pictor and Puppis. 2014 RC fades rapidly after its swing by Earth and will quickly become impossible to see in all amateur telescopes, though time exposure photography will keep the interloper in view for a few additional hours.
Most of us won’t have the opportunity to run outside and see the asteroid, but Gianluca Masi and his Virtual Telescope Project site will cover it live starting at 6 p.m. EDT (22:00 UT). Lance Benner, who researches radar imaging of near-Earth and main-belt asteroids, hopes to image 2014 RC with 230-foot (70-m) radar dish at the Goldstone complexon September 5-7 and possibly the big 1,000-foot (305-m) radar dish at Arecibo. Both provide images based on radar echoes that show asteroids up close with shapes, craters, ridges and all.
That pale white dot up there? No. 10,000 in a list of near-Earth objects. This rock, 2013 MZ5, was discovered June 18. It is 1,000 feet (300 meters) across and will not come anywhere near to threatening Earth, NASA assures us.
But what else is out there? The agency still hasn’t found every asteroid or comet that could come by Earth. To be sure, however, it’s really trying. But is there more NASA and other agencies can do to search? Tell us in the comments.
A bit of history: the first of these objects was discovered in 1898, but in recent decades we’ve been more systematic about finding them. This means we’ve been picking up the pace on discoveries.
Congress asked NASA in 2005 to find and catalog 90 per cent of NEOs that are larger than 500 feet (140 meters) in size, about enough to level a city. The agency says it has also found most of the very largest NEOs, those that are at least six-tenths of a mile (1 kilometer) across (and none so far discovered are a threat.)
Still, NASA says once it achieves its latest goal (which it is supposed to be by 2020), “the risk of an unwarned future Earth impact will be reduced to a level of only one per cent when compared to pre-survey risk levels. This reduces the risk to human populations, because once an NEO threat is known well in advance, the object could be deflected with current space technologies.”
Several blockbuster movies, television shows and commercials have depicted the discovery of an asteroid heading towards Earth and usually, somehow, impending doom is averted. But how do the discoveries of Near Earth Objects really happen? Asteroid 2012 BX34 buzzed by Earth last week, and even though this small asteroid was never considered a threat to Earth, its discovery still piqued the interest of the public. It was discovered by Alex Gibbs, an astronomer and software engineer from the Catalina Sky Survey. Universe Today asked Gibbs to share his experiences of being an asteroid hunter and what it was like to find this latest NEO that made the Top-20 list of closest approaches to Earth.
The Catalina Sky Survey is a research program at the University of Arizona and is part of the Spaceguard Survey, a NASA project to discover and catalog Earth-approaching and Potentially Hazardous Asteroids (PHAs).
When astronomers look through telescopes, asteroids don’t look much different from stars – they are just points of light. But these points of light are moving; however they are moving slow enough that to detect the motion, astronomers take a series of images, usually four images spaced 10-12 minutes apart.
Then, the observers run specialized software to examine their images for any star-like objects that are moving from one image to the next. The software removes any candidates that correspond to known objects or main-belt asteroids.
Gibbs said the software has a low detection threshold to avoid missing anything, so the observer looks over what the software found and determines which are real. The remaining objects that the software determines could be interesting are then sent in to the Minor Planet Center (MPC) at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, for the team or others to follow up.
Gibbs said his discovery images of 2012 BX34 were taken at 10:30 UT (3:30 am in Tucson) on January 25, 2012. He was using a Schmidt telescope on Mount Bigelow. At the time, the object was 1.8 million km away, moving 1.15 degrees/day across the sky, and at 20th magnitude.
On the night of discovery, Gibbs said 2012 BX34 seemed just like most of the NEOs they find. But something unusual happened the following night.
“No one seemed to be able to find it,” Gibbs said via email. “That happens sometimes, but it should have been pretty easy for the observatories that were looking. When my colleague, Rik Hill, found a ‘new’ object nearby I was suspicious that it might be the same object. The object’s rapid increase in brightness and apparent motion had made it difficult to recognize as the same object.”
When Gibbs put the two observations together he could tell they were the same object. But more importantly, he also could tell the object was going to come fairly close to Earth.
“That’s when I emailed the MPC to point out that they were the same object,” Gibbs said.
Even though this is what Gibbs does for a living, certainly there must be a certain thrill (or butterflies in the stomach) when it is realized one of these NEOs is coming fairly close to Earth?
“We realized it was going to come pretty close, but wouldn’t impact,” Gibbs said. “I knew it was small enough that it would disintegrate if it did, so although I was excited, I was also a little disappointed that it wasn’t going to put on more of a show. But I definitely prefer this to it being TOO flashy!”
The software at the MPC also figured out this asteroid was coming close, and just like in the movies, astronomer Gareth Williams, associate director of the MPC, was aroused from his sleep in the middle of the night by a pager message. But, said Williams in an interview with the BBC, “when I saw the miss distance was going to be 10 Earth radii, I said ‘that’s too far for me to get up,’ so I rolled over and went back to sleep.”
“That explains why the emails I exchanged with him later on were so short,” Gibbs said.
At its closest approach, on January 27 15:15 UT, 2012 BX34 was 59,600 km from the Earth’s surface, moving 729 deg/day, appearing at 14th magnitude, which is 250 times brighter than when Gibbs first saw it.
Gibbs said it is common for discoveries to be followed up by others astronomers, though it’s not a rigid practice.
“Whenever we find something moving in an ‘interesting’ way we send it to the Minor Planet Center, as do all the other surveys,” he said. “The MPC publishes the objects on their public NEO Confirmation Page. Various parties then follow the objects up, both pros and amateurs. Whether an object is deemed interesting or not is primarily determined by software that looks at the motion and brightness, though we can often tell when we see it. We also submit anything that appears to have cometary features.”
As of January 29, 2012, 8,648 Near-Earth objects have been discovered, with about 840 of these NEOs being asteroids with a diameter of approximately 1 kilometer or larger. Also, 1,284 of these NEOs have been classified as PHAs.
“NEOs are ones that come within 1.3 AU of the Sun (since the Earth is at 1 AU it means they pass through our neighborhood),” Gibbs said. “ PHAs are those that are larger than about 150 m (500 ft) and come within 0.05 AU of Earth’s orbit, so that at some point in the future they may cross paths.” (See more info on PHAs here)
“The large asteroids are much brighter than objects like 2012 BX34,” Gibbs said. “We see them as they orbit the Sun, and can determine if they are likely to come close to the Earth at some point. That gives us a lot more time to do something about an impact from the most dangerous asteroids. However, we ought to be doing more to catalog all the asteroids that could potentially take out a city or cause a tsunami. We are finding them now, but not fast enough. An asteroid impact is one of the few predictable and potentially preventable natural disasters.”
Even though asteroid 2012 BX34 was one of the top-20 closest approaches by an asteroid, its size made it a non-issue. While bus-sized sounds pretty big, this is small enough that it would break apart and burn up in the atmosphere. Instead, it passed by harmlessly.
“But a close fly-by like this one serves to remind people that asteroids of all sizes do come by the Earth,” said Gibbs. “We need to be vigilant.”
As for Gibbs, he is back at his job of asteroid hunting, and tonight will be scanning the skies from a larger telescope on Mt. Lemmon in Arizona.