{"id":11520,"date":"2021-08-13T18:49:18","date_gmt":"2021-08-13T10:49:18","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/ultra-precise-tracking-virtually-rules-out-near-term-impact-by-asteroid-bennu\/"},"modified":"2021-08-13T18:49:18","modified_gmt":"2021-08-13T10:49:18","slug":"ultra-precise-tracking-virtually-rules-out-near-term-impact-by-asteroid-bennu","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/ultra-precise-tracking-virtually-rules-out-near-term-impact-by-asteroid-bennu\/","title":{"rendered":"Ultra-precise tracking virtually rules out near term impact by asteroid Bennu"},"content":{"rendered":"

STORY WRITTEN FOR CBS NEWS & USED WITH PERMISSION<\/p>\n

\"\"
This mosaic of Bennu was created using observations made by NASA\u2019s OSIRIS-REx spacecraft that was in close proximity to the asteroid for over two years. Credits: NASA\/Goddard\/University of Arizona<\/figcaption><\/figure>\n

In September 2135, the 1,600-foot-wide asteroid Bennu will pass between the Earth and the moon and while scientists said Wednesday there is no chance of a collision, Earth\u2019s gravity will alter the interloper\u2019s trajectory, raising the possibility of an impact during a subsequent close encounter.<\/p>\n

It all depends on how Bennu\u2019s trajectory is affected by Earth\u2019s gravity, the long-range gravitational influence of other plants and asteroids and perturbations caused by more subtle factors, including the effects of solar heating.<\/p>\n

The latter is known as the Yarkovsky effect, a tiny acceleration produced when the heat absorbed from the sun is radiated back into space as an asteroid rotates from daylight to darkness and rocks cool down.<\/p>\n

\u201cThe Yarkovsky effect acting on Bennu is equivalent to the weight of three grapes,\u201d said Davide Farnocchia, a researcher at the Center for Near Earth Object Studies at the Jet Propulsion Laboratory and lead author of a paper describing Bennu\u2019s path in the journal Icarus.<\/p>\n

\u201cThink about that. Just three grapes, and that\u2019s what\u2019s really driving the motion of Bennu into the future, because this acceleration is persistent, its effect builds up over time, and it becomes very significant by the time we get to 2135.\u201d<\/p>\n

Thanks to NASA\u2019s OSIRIS-REx spacecraft, which spent two years orbiting the sun in concert with Bennu and is now heading home with a treasure trove of collected rock samples, researchers have been able to more accurately model those forces to determine Bennu\u2019s future course.<\/p>\n

Ultra-precise tracking of the spacecraft and its motion around Bennu, reflected in slight changes in probe\u2019s radio signals, allowed researchers to nail down the parameters of the asteroid\u2019s orbit to within about 6 feet.<\/p>\n

\u201cWe measured the distance between the Earth and Bennu, which at times was as large as the distance between the Earth and the Sun, with a precision of two meters,\u201d Farnocchia said. \u201cThat\u2019s the height of a basketball player.\u201d<\/p>\n

Before the OSIRIS-REx mission, analysts had identified 26 half-mile-wide gravitational \u201ckeyholes\u201d along Bennu\u2019s path in the 2135 encounter. If Bennu\u2019s trajectory, influenced by the Yarkovsky effect or other factors, passed through one of those keyholes, Earth\u2019s gravity could then put the asteroid on a collision course.<\/p>\n

Thanks to the exquisite tracking precision, the researchers were able to rule out all but two such keyholes to come up with the most accurate assessment of Bennu\u2019s impact potential to date.<\/p>\n

And the odds remain comfortably low: just a 0.06 percent chance of a collision on Sept. 24, 2182, the date of the most likely near-term encounter, which means a 99.94 percent probability Bennu will miss.<\/p>\n

\u201cThere is no particular reason for concern,\u201d said Farnocchia. \u201cWe know that Bennu is still a potentially hazardous asteroid, but the probability is small, and we have time to keep tracking the asteroid and eventually come to a final answer.\u201d<\/p>\n

Bennu is classified as a \u201cpotentially hazardous\u201d body because it\u2019s orbit periodically intersects Earth\u2019s. And while impact by a 1,600-foot-wide asteroid like Bennu would not trigger a mass extinction like the 6-mile-wide body that wiped out the dinosaurs 66 million years ago, it would still wreak widespread devastation.<\/p>\n

Lindley Johnson, a planetary defense officer at NASA\u2019s Planetary Defense Coordination Office, said the crater produced in an impact is typically 10 to 20 times the size of the impacting body.<\/p>\n

\u201cSo a half-kilometer sized object (like Bennu) is now going to create a crater that\u2019s at least five kilometers in diameter and it could be as much as 10 kilometers (6 miles) in diameter,\u201d he said. \u201cBut the area of devastation is going to be much, much broader than that, as much as 100 times the size of the crater.<\/p>\n

\u201cAn object Bennu\u2019s size impacting on the Eastern Seaboard would pretty much devastate things up and down the coast.\u201d<\/p>\n

But as the researchers pointed out, the odds of such an impact are remote.<\/p>\n

\u201cWe should remember that the risk carried by Bennu as an individual asteroid is actually smaller than the risk coming from the undiscovered population of objects of a similar size,\u201d Farnocchia said. \u201cAnd that\u2019s why NASA is making a big effort to discover more than 90 percent of the near Earth objects greater than 140 meters (460 feet) in size.\u201d<\/p>\n

Lindley said about 60 percent of the presumed population has been identified to date.<\/p>\n","protected":false},"excerpt":{"rendered":"

STORY WRITTEN FOR CBS NEWS & USED WITH PERMISSION This mosaic of Bennu was created using observations made by NASA\u2019s OSIRIS-REx spacecraft that was in close proximity to the asteroid for over two years. Credits: NASA\/Goddard\/University of Arizona In September 2135, the 1,600-foot-wide asteroid Bennu will pass between the Earth and the moon and while scientists said […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[],"class_list":["post-11520","post","type-post","status-publish","format-standard","hentry","category-news"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/11520"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=11520"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/11520\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=11520"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=11520"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=11520"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}