|
Science briefs: August 22
Posted: Fri, Aug 23, 2002, 8:01 AM ET (1201 GMT)
- Scientists have found evidence that an asteroid collided with the Earth nearly 3.5 billion years ago. Rocks in South Africa and Australia contain spherules of material created during asteroid impacts; radioactive uranium dating of those rocks showed that they are 3.47 billion years old. Scientists don't believe the impact would have had a major impact on the development of life on Earth, since only bacteria existed on the Earth at the time.
- A "cosmic smog" of organic molecules may have existed when the solar system formed, helping seed the Earth with the building blocks required for life to form, New Scientist reported this week. Scientists determined that polycyclic aromatic hydrocarbons (PAHs) found in meteorites were not altered after the meteorite formed, implying that they existed in the cloud of gas and dust from which the solar system formed nearly five billion years ago. Scientists suggest that this means that the building blocks for life may be commonplace in other solar systems as well.
|
|
