Category Archives: Astronomy

Q: Why does the Earth orbit the Sun?

The original question was: What exactly causes the Earth’s rotation and revolution?  Does this occur due to centripetal force and the lack of friction to stop the Earth from spinning? IE- Newton’s First Law? If so, where did this centripetal … Continue reading

Posted in -- By the Physicist, Astronomy, Equations, Physics | 63 Comments

Q: What would Earth be like to us if it were a cube instead of spherical? Is this even possible?

Physicist: The Earth is really round.  It’s not the roundest damn thing ever, but it’s up there.  If the Earth were the size of a basketball our mountains and valleys would be substantially smaller than the bumps on the surface … Continue reading

Posted in -- By the Physicist, Astronomy, Physics | 85 Comments

Q: What is the universe expanding into? What’s outside the universe?

Physicist: Probably nothing.  We do know that the universe doesn’t need anything to expand into, and we haven’t seen any evidence that there is anything outside of the universe.  But there has still been some speculation. In the last hundred … Continue reading

Posted in -- By the Physicist, Astronomy, Philosophical, Physics | 63 Comments

Q: Is there a single equation that proves black holes are real?

Physicist: Nope! Using general relativity (which has plenty of equations), and a little borrowed knowledge from other fields (to describe star collapse), you can show that black holes should exist.  But unfortunately there are no proofs in physics, just experimental … Continue reading

Posted in -- By the Physicist, Astronomy, Philosophical, Physics | 11 Comments

Q: What is the evidence for the Big Bang?

Physicist: The very short answer is: all the galaxies in the universe are flying apart, so at some point in the distant past they must have been very close together.  It would have been so close and so dense that … Continue reading

Posted in -- By the Physicist, Astronomy, Physics | 13 Comments

Q: Can we build a planet?

Physicist: In theory, there’s nothing standing in the way.  In fact by constructing a planet from asteroids, comets, or dust you can expect to get a fair amount of energy back out.  Normally, you’d just chuck a bunch of dust, … Continue reading

Posted in -- By the Physicist, Astronomy, Physics | 30 Comments