Nasa: Jätteasteroid träffar inte jorden inom hundra år

99942 Apophis () is a near-Earth asteroid with a diameter of 370 metres (1,210 feet) that caused a brief period of concern in December 2004 when initial observations indicated a probability up to 2.7% that it would hit Earth on April 13, 2029. Additional observations provided improved predictions that eliminated the possibility of an impact on Earth in 2029. However, until 2006, a possibility remained that during the 2029 close encounter with Earth, Apophis would pass through a gravitational keyhole, a small region no more than about 800 metres (1⁄2 mi) in diameter, that would set up a future impact exactly seven years later on April 13, 2036. This possibility kept it at Level 1 on the Torino impact hazard scale until August 2006, when the probability that Apophis would pass through the keyhole was determined to be very small and Apophis's rating on the Torino scale was lowered to zero. By 2008, the keyhole had been determined to be less than 1 km wide. During the short time when it had been of greatest concern, Apophis set the record for highest rating on the Torino scale, reaching level 4 on December 27, 2004.The diameter of Apophis is estimated to be approximately 370 metres (1,210 ft). Preliminary observations by Goldstone radar in January 2013 effectively ruled out the possibility of an Earth impact by Apophis in 2036. By May 6, 2013 (April 15, 2013 observation arc), the probability of an impact on April 13, 2036 had been eliminated. Apophis will make two modest approaches to Earth in 2036, but even the planet Venus will come closer to Earth in 2036. On April 12, 2068 the nominal trajectory has Apophis 1.87 AU (280 million km) from Earth. Entering March 2021, there were six asteroids with a more notable cumulative Palermo Technical Impact Hazard Scale than Apophis, though none of them has a Torino level greater than 0. On average, an asteroid the size of Apophis (370 metres) can be expected to impact Earth once in about 80,000 years. Observations in 2020 by the Subaru telescope have confirmed David Vokrouhlický's 2015 Yarkovsky effect predictions. Goldstone radar observed Apophis March 3-11, 2021 helping to refine the orbit. On March 25, 2021 the Jet Propulsion Laboratory announced that Apophis has no chance of impacting Earth in the next 100 years. It was removed from the Sentry Risk Table the next day.