TED Talks: Space Trek
Brilliant minds give clues about ancient celestial life
forms, future spacecraft and the universe's most peculiar places. Experts offer
their entertaining explanations of cosmic phenomena, space travel and the
possibility of extraterrestrial life.
99942 Apophis (/əˈpɒfɪs/, previously known by its provisional
designation 2004 MN4) is a near-Earth asteroid that caused a
brief period of concern in December 2004 because initial observations indicated
a probability of up to 2.7% that it would hit Earth
in 2029. Additional observations provided improved predictions that eliminated
the possibility of an impact on Earth or the Moon in
2029. However, 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 m (half a mile) wide,[7] that would set up a future impact on
April 13, 2036. This possibility kept the asteroid 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. Apophis broke the record for the highest level on the Torino Scale,
being, for only a short time, a level 4, before it was lowered.[8]
************************************** From HHMI - Howard Hughes Medical InstituteEducational Material http://www.hhmi.org/educational-materials
Series: Changing
Planet: Past, Present, Future
The Holiday Lectures on Science series brings current
research into the science classroom. http://www.hhmi.org/node/19795
You can start here with Lecture 1 from 2012, (Top navigation list leads to All lectures since 1995) http://media.hhmi.org/hl/12Lect1.html
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