Spaceflight Insider

Huge asteroid to zip by Earth on Halloween

Artwork of a potentially-hazardous asteroid approaching the Earth.

Artwork of a potentially-hazardous asteroid approaching the Earth. Image Credit: Jeff Darling

A giant asteroid, designated 2015 TB145 , will zip by the Earth on Oct. 31 at a distance of around 1.3 lunar distances (LD) – approximately 310,000 miles (499,000 km). The space rock, nicknamed “Spooky” is about 1,542 feet (470 meters) in diameter and was recently spotted by NASA’s Pan-STARRS I survey. The space research team expects the asteroid to fly by our planet with a speed of 78,000 mph (125,529 km/h). 2015 TB145 is the biggest known asteroid to sweep near Earth until 2027.

The closest approach will occur at 11:14 a.m. ET (15:14 UTC). The asteroid is following an eccentric and high-inclination orbit, which may help explain why it was not discovered until Oct. 10 of this year.

“The asteroid is on an extremely eccentric and a high inclination orbit,” NASA said in a statement. “Its absolute magnitude of 19.9 indicates that its diameter is probably within a factor of two of 320 meters.”

Amateur astronomers may be able to see the moving asteroid in telescopes of 8ʺ (20 cm) diameter or larger. The asteroid will be traveling across the constellation of Orion.

NASA hopes to obtain high-resolution images of the asteroid as it passes. The radio astronomy installations at both Deep Space Network in Goldstone, California, and the Arecibo array in Puerto Rico intend to track and record the path of 2015 TB145 via radar, which should provide invaluable data for future near-Earth asteroid encounters.

“We hope to obtain images with a range resolution as high as 2 m/pixel using DSS-13 [DSN’s antenna] to transmit and Green Bank, and possibly Arecibo, to receive. The flyby presents a truly outstanding scientific opportunity to study the physical properties of this object,” the space agency said.

NASA describes 2015 TB145 as being potentially “hazardous”, although they are sure that it poses no danger and will not hit Earth.

“Spooky” will also miss the Moon the same day at about 0.74 LD. Its next Earth flyby will take place on Oct. 9, 2125; however, it is hard to call it a flyby as the asteroid should not come any closer to Earth than 189 LD.

This is the closest approach by a known object this large until (137108) 1999 AN10 approaches within 1 LD in August of 2027.

According to NASA’s Near-Earth Object (NEO) Observations Program, 13,251 near-Earth objects have been discovered, 877 of which are asteroids with a diameter of approximately 1 kilometer or larger.

As of Oct. 21, 2015, there were 1,629 potentially hazardous asteroids (PHAs). PHAs are space rocks larger than approximately 328 feet (100 meters) that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.



Tomasz Nowakowski is the owner of Astro Watch, one of the premier astronomy and science-related blogs on the internet. Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate. Nowakowski's generous offer was gratefully received with the two organizations now working to better relay important developments as they pertain to space exploration.

Reader Comments

Hey there is the earth safe ur not there loads asteroid coming near us alot

Hi Tracy,
Per the story’s 7th paragraph: “NASA describes 2015 TB145 as being potentially “hazardous”, although they are sure that it poses no danger and will not hit Earth.

Sincerely, Jason Rhian – Editor, SpaceFlight Insider

I don’t think that’s what Tracy meant. We track “potentially hazardous” NEO rocks very closely, and the math on their orbits is old hat and very precise.
However, THIS rock came out of nowhere and we’ve only known about it for about twelve days.
I think what she wants to know, and so do I, is how often do we discover a new rock just three or four weeks before a close flyby? I’ll add to that…How precise is the math on a rock that we’ve only been watching for twelve days?

Hi Bill,
Thanks for that clarification. As was the case with the Chelyabinsk meteor, which struck with little-to-no warning – there are more than a few of these objects that we’re completely unaware of. We do monitor the path of a good many NEOs.
From what I understand, once scientists know the general position/speed of one of these objects – they have a fairly good grasp of what it’s trajectory is. Sorry, I know that’s not very specific.
Sincerely, Jason Rhian – Editor, SpaceFlight Insider

Although it is clearly stated that the asteroid will not hit earth, what kind of damage could something like this potentially do?

Hi Nick,
Here’s a link to a NASA page with some information on the subject. Let me know if you want to know more and we’ll get it to you:

Sincerely and with kind regards, Jason Rhian – Editor, SpaceFlight Insider

Perfect, thanks!

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