Astronomers are always watching the skies for observations of near-Earth asteroids—”space rocks” that have orbits close to Earth’s and, in the case of potentially hazardous asteroids (aka PHAs), those whose orbits could actually cross Earth’s and are larger than 150 meters (500 ft) across. When a new one of these is discovered—no small feat considering that many are very dark, move quickly, and could really be anywhere in the sky—it’s a scramble to determine the object’s orbital parameters and figure out just how close it can get to us and when. Such was the case on Oct. 19, 2016, when the asteroid 2016 WJ1 was identified with the Catalina Sky Survey. This object, estimated to be anywhere from 110 to 340 meters across—easily within the potentially hazardous range—was initially calculated to pose a threat in 2065 with a possible impact risk, albeit a very small one. Eventually though, scientists were able to refine the risk chance with more observations of 2016 WJ1…observations that had actually occurred over 13 years earlier.
Read the full story from ESA here: Asteroid sleuths go back to the future
On the afternoon of Oct. 31, 2015, Earth was visited by something much creepier than the typical Halloween trick-or-treater: a dark 2,000-foot (600-meter) -wide asteroid that sped silently (because space) by, approaching at its closest only about 1.3 times the distance to the Moon.
Designated 2015 TB145, this particular near-Earth object had only just been discovered a couple of weeks earlier. And while it posed no danger of impact, its considerable size and high velocity made the close pass a topic of interest for laypeople and scientists alike. By bouncing radar waves off its surface NASA researchers were able to generate an image of 2015 TB145, capturing details that would have been otherwise impossible due to its high velocity and incredibly dark coloration.
Yes, it’s true: a rather not-so-tiny near-Earth
asteroid SKULL-SHAPED ZOMBIE COMET (see below) 2015 TB145 will make a relatively close pass by our dear planet Earth on October 31, aka Halloween — the day when certain beliefs profess that the veil separating the worlds of the living and the dead is at its thinnest, allowing spiritual and even physical interaction to occur between both.
Of course there is no scientific evidence that the latter is at all true but it makes for good scary stories around the light of a campfire. And as the first-world campfires of today are the stark lights of computer monitors and smartphone screens, some are trying to weave scary stories about the passing of this asteroid as well. Should you be afraid? Certainly not. (But there is a cautionary tale to be told.)
Just under two weeks from now, on Monday, Jan. 26, the 1/3-mile (0.5-km) -wide potentially hazardous asteroid 357439 (2004 BL86) will pass by Earth at 3.1 lunar distances, or 739,680 miles (1,190,400 km). While this may sound like a long way off, in the grand scheme of things it’s still a close pass… especially for an object as wide as the Burj Khalifa is high!
Don’t worry though – there’s no risk of an impact from 2004 BL86. It will go sailing by harmlessly at a relative 15.6 km/s velocity (that is, 34,900 mph) back out into the Solar System, just another rocky reminder that Earth is definitely not alone out here.
And, thankfully, astronomers will be watching.
Telescope twin powers: ACTIVATE! Form of… an asteroid?
Okay, so the telescopes involved aren’t twins — one is a giant 70-meter dish in California’s Mojave Desert and the other is a 305-meter behemoth high in the Puerto Rican rain forest — they did combine their powers to image the passing asteroid 2014 HQ124 on June 8 as it came to within about 3 lunar distances, obtaining some of the highest-resolution data of a near-Earth asteroid ever.
Before the pass this object was being called “the beast,” but once astronomers bounced some radar off it its true beauty shined through. Read more in my Discovery News article here.
Image credit: NASA/JPL-Caltech/Arecibo Observatory/USRA/NSF