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Wow. A low-flying space rock set a record last Friday (appropriately, 13th), when the 2020 VT4 passed just under 400 kilometers (250 miles) over the South Pacific.
The an asteroid has been identified from the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey at the Mauna Loa Observatory in Hawaii in the early morning hours of Saturday, November 14, just 15 hours after the approach. This is not uncommon for fast speeds, especially asteroids that are coming to Earth from our blind spot towards the sun, such as 2020 VT4.
The newly discovered asteroid A10sHcN approached Earth yesterday, passing only a few hundred miles above the South Pacific Ocean. This encounter shortened its orbit, ensuring that this Earth cruiser will make more frequent approaches. Http://t.co/TmkzojIzPf pic.twitter.com/XrnKiiGTyJ
– Tony Dunn (@ tony873004) November 14, 2020
Asteroid 2020 VT4 is estimated to be 5-10 meters (16-32 feet) in diameter, about the size of a small house. Earth failed to occupy the same space as the perihelion point for the asteroid, which occurred just 20 hours prior to Earth’s passage.
This sets a record for the closest documented non-meteoric asteroid passage against Earth. This record has already been broken once this year, with asteroid 2020 HQ passing 3,000 kilometers (1,864 miles) from the Earth’s surface on August 16. A brilliant fireball was captured on video on the afternoon of 10 Augustth, 1972, when it became a brilliant daytime fireball over the Grand Teton Mountains in Wyoming before turning back from Earth’s atmosphere. Another recent record was set in October 2008, when astronomers sighted a 4-meter (13-foot) 2008 TC3 asteroid 19 hours before impact, and later recovered fragments in the Nubian Desert in northern Sudan two months. later, making 2008 TC3 the first asteroid that has been documented before is after impact.
Unfortunately, the close passage of asteroid 2020 VT4 appears to have gone without witnesses; the closest approach occurred at 5:20 pm universal time (UT) on Friday 13 Novemberth over the South Pacific near the Pitcairn Islands under daytime skies and followed the edge of the outgoing Earth shadow. For context, the International Space Station also orbits 400 kilometers (250 miles) above the surface of the Earth, and is 109 meters (358 feet) from tip to tip … 2020 VT4 would certainly have been visible as a + Una ” star “of magnitude 3 on its outbound stretch of southern Tasmania in the pre-dawn sky, had an island-bound observer or a morning sailor who was watching. No satellite (including the ISS, which was over the South Atlantic at the time) was affected by the 2020 VT4 passage, although it certainly passed through the sphere of geostationary satellites and touched the ring of low Earth orbit.
Had it hit Earth, 2020 VT4 would have simply put on a good show, and perhaps it would have left a field strewn with meteorites in its wake. For context, the asteroid that produced the 2013 Chelyabinsk event was thought to be 20 meters in diameter.
This step actually substantially altered the orbit of 2020 VT4. On entry, the asteroid was on a 549-day orbit around the Sun, tilted 13 degrees to the ecliptic … its encounter with the massive Earth deflected it into a 315-day orbit tilted 10, 2 degrees with respect to the ecliptic plane. With a perihelion now within the orbit of Venus, this actually changes the classification of the 2020 VT4 from a NEO Apollo ground cruiser to an Aten asteroid.
On November 13, 2020, VT4 will visit Earthth 2052 with a passage of 0.02 AU (1.8 million nominal miles) much further away.
2020’s VT4 record will be hard to break … but 2020 is far from over.
Main image: An artist’s impression of an asteroid crossing the Earth. Credit: ESA / P. Carril
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