What would happen if two people out in space a few meters apart, abandoned by their spacecraft, decided to wait until gravity pulled them together? My initial thought was that it would take a really long time, longer than they would practically be able to wait. The calculation (unless I've done something wrong) seems to indicate otherwise.

My first approach, which is approximate, is to determine the resulting kinetic energy when they come together and assume (badly) that it was a constant acceleration to determine the time. This will low-ball the time but be easy to calculate. My second approach is to numerically simulate the system in pyndamics3. If I feel like it, I might do the integral later, but after the first approximation I like to look at things numerically (mostly for fun).

which clearly shows them coming together in around 1/2 of a day, from their own gravity. I guess I have to adjust my intuitions for such situations.

Popular Posts

Gravitational Attraction

What would happen if two people out in space a few meters apart, abandoned by their spacecraft, decided to wait until gravity pulled them together? My initial thought was that …

A Simple Physics Problem Gets Messy

A physics problem from a practice AP test came to my attention, when my daughter was in AP physics this past spring. I went over her solutions when she did …

Skepticism and Dubious Medical Procedures

In my discussion with Jonathan McLatchie on the Still Unbelievable podcast, I said that there hasn’t been a verified miracle claim even since Hume’s essay on miracles. Here I look into the papers he references in response.

Get in touch

What problems are you interested in? How can I help?