"Are we from adam or we are from monkey? if we are somehow like a monkey why the other ones couldn't be humans? "
-
Question
How do you disprove that an asteroid caused extinction?
There are many causes of extinctions, but I presume you are interested primarily in mass extinctions, when a substantial fraction of all life dies out in a single environmental catastrophe. In the one case of the end-Cretaceous (KT) mass extinction 65 million years ago, we are pretty sure that the cause was the collision of the Earth with a comet or asteroid about 15 km in diameter, which left the impact crater in Mexico that we now call Chicxulub. This conclusion has been supported by many lines of evidence, and very few scientists remain unconvinced today. In no other case, however, is there similar strong evidence for an impact associated with a mass extinction. There are some suggestive data, but nothing that might be called "proof". However, there is also nothing that "disproves" the hypothesis that an impact was associated with these mass extinctions, and I don't know what could disprove this hypothesis -- except perhaps an alternative explanation that is more strongly supported by the evidence. For more information on impacts and mass extinctions you might want to read the books "Extinction: Bad Genes or Bad Luck" by David Raup, "Night Comes to the Cretaceous" by James Powell, or "When Life Nearly Died" by Michael Benton.
David Morrison
NAI Senior Scientist
October 16, 2003
- How frequently are questions answered?
- I asked a question but there was no answer?
- Who is the Astrobiologist answering these questions?
- Will I get an email when my question is answered?
- What college courses should I take to become an astrobiologist?
- How can I get a job as an astrobiologist at NASA?
- Have aliens visited Earth? Are UFOs real?
- Is there a planet or brown dwarf called Nibiru or Eris that is approaching the Earth and threatening our planet with widespread destruction?
- Is it true that the Sun will be in the center of the Milky Way Galaxy in December 2012 and that this will cause a pole shift and massive destruction.
- Has NASA discovered life on other worlds?
- Astrobiology Career Path Suggestions
