Category Archives: Astronomy

Q: How does Earth’s magnetic field protect us?

Physicist: High energy charged particles rain in on the Earth from all directions, most of them produced by the Sun.  If it weren’t for the Earth’s magnetic field we would be subject to bursts of radiation on the ground that … Continue reading

Posted in -- By the Physicist, Astronomy, Particle Physics, Physics | 3 Comments

Q: If time slows down when you travel at high speeds, then couldn’t you travel across the galaxy within your lifetime by just accelerating continuously?

Physicist: Yup!  But sadly, this will never happen. This is a good news / really bad news situation.  On the one hand, it is true (for all intents and purposes) that if you travel fast enough, time will slow down … Continue reading

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

Q: If nothing can escape a black hole’s gravity, then how does the gravity itself escape?

Physicist: A black hole is usually described as a singularity, where all the mass is (or isn’t?), which is surrounded by an “event horizon”.  The event horizon is the “altitude” at which the escape velocity is the speed of light, … Continue reading

Posted in -- By the Physicist, Astronomy, Physics, Relativity | 27 Comments

Q: Why are many galaxies, our solar system, and Saturn’s rings all flat?

Physicist: This may be the shortest answer yet: “accretion“. Accretion is the process of matter gravitationally collapsing from a cloud of dust or gas or (usually) both.  Before thinking about what a big cloud of gas does when it runs … Continue reading

Posted in -- By the Physicist, Astronomy, Physics | 8 Comments

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 | 20 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 | 16 Comments