Asteroid

Hey, we already know that dinosaurs extinct by the 100,000 tons of nuclear bombs meteor caused extinction to them. But what time did this happen? How do we know?

Well, …, embedded in rock, over the entire earth is a thin layer of iridium. It’s known as the K-T boundary (see link below). Below this layer there’s evidence of life and life in abundance via fossil evidence. In the layer and immediately above it … no life (i.e. no fossils) until many many years later, thus, indicating that global extinction occurred. Most scientists agree that this happened in the cretaceous period roughly 65 +- 0.3 million years ago. There is also a massive (mostly underwater) impact crater that was discovered a few years ago off the coast of Yucatan. It too dates to roughly 65 +- 0.3 million years ago and, since meteors (composed of carbonaceous chondrites) contain a high concentration of iridium, it’s highly probable that the massive global extinction event was caused by that meteoric impact.

Do we know for sure? No. It’s a theory, but a highly probable one. This particular impact may not have been the lone smoking gun. There appears to have been many impacts during that particular period of time, coupled with and uptick in geologic vulcanism, as well as, the evidence that dinosaurs were literally destroying their own environment (and themselves) due to their voracious appetites for plant life and one another. As a result, the dinosaurs of that particular era were doomed to extinction on at least 3 levels: themselves, geologic vulcanism (or volcanism), and finally, death from above. Let’s face it they were doomed!

A meteor is visible only once, but a comet may be visible at regular intervals throughout its lifetime. Why?

Comets are much farther away and do not impact the
Earth.

Meteor is 2000 meters wide and made of ice and impacts the water/ocean.

What would the damage be on the entire earth.

Depends on the size of the meteor.

I’ve heard a little bit about a meteor that is due to come close to or near earths orbit in 2027 and possibly but probably not make impact. Is this true?

Apophis is supposed to make its return in 2027. IF Apophis comes too close to Earth in that year, the gravitational affect due to Apophis’ close proximity to Earth can change its trajectory for it to come back around and set it for a collision course with Earth in 2032. The possibility is slim but it’s still there.

As a side question, are the meteor fragments they sell at the gift shop there real and from that crater?

It’s a great question, but it could be a trifle misleading. The meteor in question was an Iron/Nickel type. Most space rocks are stony or even carbonaceous. Allowing for similar impact velocities and angles, you get decidedly different craters.

http://www.lpl.arizona.edu/impacteffects/

Here is a program that will help you simulate the different impacts.

Have fun!

OK so my sister told me that the biggest meteor shower of 2009 starts tonight but she does not know what time and I’m having trouble finding a straight answer on Google. So please if anyone knows what time the meteor shower starts (and if there is even one she’s gets her facts wrong alot) please tell me! Thanks!

on facebook an event says it starts at 9 on the east coast, so if you live anywhere else, try to figure out the time to where you live.

try this:

http://www.spacedex.com/locations/index.php