Category Archives: Astronomy

Q: How can the universe expand faster than the speed of light?

Physicist: You’ll often hear that “the universe is expanding faster than the speed of light”.  However, this statement is akin to statements like “green is bigger than happy”.  It’s not even wrong. There are two big things to remember about … Continue reading

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

Q: How fast are we moving through space? Has anyone calculated it?

The original question was: Considering the spin of the earth, it’s orbit around the sun, the sun’s orbit around the Milky Way and the Milky Way’s journey through interstellar space, has anyone calculated our speed though the universe? Physicist: The … Continue reading

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

Q: What role does Dark Matter play in the behavior of things inside the solar system?

Physicist: To a stunningly good approximation: zero. The big difference between dark matter and ordinary matter is that dark matter is “aloof” and doesn’t interact with other stuff.  Instead, it cruises by like “ghost particles”.  Matter on the other hand … Continue reading

Posted in -- By the Physicist, Astronomy, Physics | 17 Comments

Q: Could the tidal forces of the Sun and Moon be used to generate power directly?

The original question was: If a machine enclosed in a building could, as I think it could, detect the tidal forces of the sun and moon upon the Earth could the effect be used to extract useful energy from those … Continue reading

Posted in -- By the Physicist, Astronomy, Engineering, Physics | 5 Comments

Q: What would it be like if another planet just barely missed colliding with the Earth?

Physicist: There’s a long history of big things in the solar system slamming into each other.  Recently (the last 4.5 billion years or so) there haven’t been a lot of planetary collisions, but there are still lots of “minor” collisions … Continue reading

Posted in -- By the Physicist, Astronomy, Physics | 10 Comments

Q: Are white holes real?

Physicist: The Big Bang is sometimes described as being a white hole.  But if you think of a  white hole as something that’s the opposite of a black hole, then no: white holes aren’t real. They show up when you … Continue reading

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