Asteroid 2012 KT42 zips only 8,700 miles from Earth tonight

2012 KT42 was nabbed as it move across the sky earlier today. Credit and a big thanks to: Ernesto Guido, Nick Howes and Giovanni Sostero

2012 KT42 was discovered earlier today May 28 by the Mt. Lemmon Survey’s 1.5-meter (59-inch) reflecting telescope north of Tucson, Arizona. The tiny asteroid was only 18th magnitude and estimated at between 10-30 feet wide. While posing no threat, it’s moving rapidly towards closest approach to Earth around 2:10 a.m. CDT tomorrow morning May 29, when it will fly by at the slim distance of 8,700 miles. That would make 2012 KT42 the 6th closest asteroid approach to date. Click HERE to see a list of Top 20 closest approaches.

Earth gets a visit from asteroid 2012 KT42 overnight. The diagram shows the time of closest approach. Credit: JPL/NASA

Savvy amateurs with 6-inch telescopes and larger should be able to see it shining between 12th and 13th ┬ámagnitude late tonight through tomorrow morning. Watch out though – the asteroid will move very rapidly across the sky. You’ll need to download its orbital elements at this site and put them into a sky-charting program, so you can make a detailed map to find and follow the zippy rock. Or … you can go to the same site, click the Ephemeris heading, select the date and time interval and then click the Generate Ephemeris button to create a list of positions you can hand plot on a sky chart.

The asteroid will transit across the face of the sun tomorrow for parts of Asia and Africa. It will only be about 6 seconds wide - very tiny. Click map for larger version. Thanks and credit to: Aldo Vitagliano

Once you do find it, don’t let go. You’ll be on a fast train. When closest, 2012 KT42 will be traveling at over 2 arc minutes per second. Two arc minutes is more than twice as big as Jupiter appears through a telescope. That’s plenty fast enough to see move in real time.

Between 1 and 3 a.m. CDT, 2012 KT42 will travel from the constellation Libra in the southern sky all the way to Auriga in the far north!

Viewers along a path that cuts across central Asia and Africa will see the asteroid transit the sun at around 5:10 CDT May 29. It’ll be interesting to see if anyone can spot it through a telescope given its minute size.

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About astrobob

My name is Bob King and I work at the Duluth News Tribune in Duluth, Minn. as a photographer and photo editor. I'm also an amateur astronomer and have been keen on the sky since age 11. My modest credentials include membership in the American Association of Variable Star Observers (AAVSO) where I'm a regular contributor, International Meteorite Collectors Assn. and Arrowhead Astronomical Society. I also teach community education astronomy classes at our local planetarium.

10 thoughts on “Asteroid 2012 KT42 zips only 8,700 miles from Earth tonight

  1. Hi bob it comes closest to earth at 2:10 am eastern or central time? & are u gonna see it? And are u sure it poses no threat? Being they just noticed it they can tell?? Its small right wouldnt it break in our atmosphere if it did hit earth? Thanks so much

    • Milayla,
      It’s 2:10 CDT or Central Daylight Time. 3:10 Eastern. No threat – even if it did enter our atmosphere, and it’s a long way from that, it’s so small it would almost certainly break into pieces, most of which would burn up.

  2. Are you positive it isn’t visible with the naked eye. My husband saw something really bright traveling in the sky at about 2am Central.

    • Hi Paula,
      Yes, I’m positive. It was only visible in a telescope. I watched it myself this morning and it was only about 11th magnitude at brightest. You may have seen a satellite.

  3. Hi Bob,
    As you said, this asteroid would have posed no threat as it would have burned up in the atmosphere as do most of the small ones, which is just as well as quite a lot of them seem to be found weeks or maybe hours before close approach, as to the large ones over 1 km that can do serious damage locally or worldwide, do you think any of these ones would ever just be found hours or weeks before they were going to hit, as I understand that over 90% of these large ones have already been found, but someone once told me that we would know well in advance that something that large was a threat to earth, I’m always worried that one over 1 km could just appear and not get much warning like that smaller ones do, and how large would one have to be to do catastrophic damage to us. Thanks Bob :)

    • Hi Lynn,
      Yes, it certainly is possible that a 1 km asteroid could still sneak by. If something that big survived entry intact, that would cause destruction over a large region. A 10 km asteroid would affect the entire planet as apparently happened 65 million years ago during the extinction of the dinosaurs.

  4. At what distance is it possible for earths gravity to pull an object toward earth. I heard it about the same distance away from earth as some satilites. I guess NASA will have a report about a close call with an asteroid, AFTER it hopefully passes us, as usuall.

    • Angelo,
      That would vary depending on the object’s speed. Geosynchronous satellites are just 22,236 miles up and they stay put just fine. They’re only moving at around 6800 mph and are expected to remain in orbit for a very long time. Most near-Earth asteroids are moving fast, in the range of 7200 to 61,000 mph. While they may be tugged by Earth, they’re moving too fast to get pulled right in. If an asteroid were to get close enough to actually pass through the upper atmosphere, friction would slow it further and potentially bring it down. That’s what happens when a meteorite falls. So I guess I can’t answer your question definitively as to exact distance and size.

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