Lets also assume that it is very rare among planets to be Earth like. Again only 1 in a million, and this is very conservative because we are assuming that only earth like planets are suitable for life. ... There are up to 50 billion planets like earth in our own Milky Way galaxy. ... The existence of earth does not imply anything about the probability of life elsewhere, because if there was no life here, we would not be exist to observe it. ... We are sitting on the surface of the earth and it takes enormous energy to get us out because of our gravity. ...

• Word Count: 2961
• Approx Pages: 12

As did all of the cosmologists in the first stage, the Greeks were absolutely sure that the Earth must be still. ... Copernicus was the first to suggest that maybe; just maybe, the Earth was not the center of the Universe. ... Newton was one of the first to realize that the rules, which governed the movement and interactions of objects in our world, also applied to the movement and interaction of objects far from Earth. ...

• Word Count: 3486
• Approx Pages: 14
• Has Bibliography

Time for a stationary observer on earth and for an astronaut on a spaceship of high velocity is different. ... As an example, astronauts traveling at 99% the speed of light could make a trip to the star Procyon that is 11.4 light-years away in 23 earth years round trip (Hewitt 229). ... The ship would take the machine on a journey while being connected to the other on earth via the wormhole. ...

• Word Count: 2726
• Approx Pages: 11
• Grade Level: High School

For as long as the Earth has been around, humans have looked up in awe at the night sky and wondered about the intricate pieces that make up what is our universe. For most of Earth's history, the universe only encompassed what was visible to the naked eye. ... Such a star would obviously not be visible on Earth because its light would never reach us, but Mitchell argued that it might be possible to detect the presence of that star by the effect that its gravitational field would have on nearby matter (Hawking 117). ... If there is a large mass concentrated in a small volume, and if the ma...

• Word Count: 3066
• Approx Pages: 12
• Has Bibliography