Category Archives: — By the Physicist

Q: Is it possible to parachute to Earth from orbit?

Physicist: Yes and no, but mostly no. It’s certainly possible to parachute safely to Earth from the top (or nearly the top) of the atmosphere, but this question isn’t about parachuting from space it’s about parachuting from orbit.  An orbit … Continue reading

Posted in -- By the Physicist, Engineering, Physics | 6 Comments

Q: Why can’t we see the lunar landers from the Apollo missions with the Hubble (or any other) telescope?

Physicist: About why you’d expect: they’re just too damn small and too damn far away.  Nothing fancy.  That’s not to say that we can never get images, just that you need to be a lot closer.  The lunar landers are … Continue reading

Posted in -- By the Physicist, Physics | 7 Comments

Q: How bad would it be if we accidentally made a black hole?

Physicist: Not too bad!  Any black hole that humanity might ever create is very unlikely to harm anyone who doesn’t try to eat it. Black holes do two things that make them (potentially) dangerous: they eat and they pop.  For … Continue reading

Posted in -- By the Physicist, Physics | 16 Comments

Q: What if gravity acted like magnetism?

Physicist: The problem with magnetism and the electric force is that they tend to cancel themselves out.  For example, if you have a positive charge the first thing it does is repel all the other positive charges around it and … Continue reading

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

Q: When you write a fraction with a prime denominator in decimal form it repeats every p-1 digits. Why?

The original question was: How come the length of the repetend for some fractions (e.g. having a prime number p as a denominator) is equal to p-1? Physicist: The question is about the fact that if you type a fraction … Continue reading

Posted in -- By the Physicist, Math, Number Theory | 6 Comments


Physicist: In 2006 a probe called New Horizons was launched to get a better look at Pluto and its moons Charon, Nix, and Hydra.  Since then, Pluto stopped being a planet and gained a couple more moons: Kerberos and Styx. This … Continue reading

Posted in -- By the Physicist | 9 Comments