Resources
Q & A
Glossary
Acronym Guide
Further Reading
Outside the Site
Google Sky
WWT
Facebook
Youtube
Vimeo
Twitter
Flickr
Pinterest
Multimedia, Etc
Images/Illustrations
Animation & Video
Special Features
Chandra Podcasts
Chandra Mobile
Desktop Images
The Big Chandra Picture
High Res Prints
Presentations
Handouts
Screen Savers
Audio
Web Shortcuts
Chandra Blog
RSS Feed
Chandra Mobile
Chronicle
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
Q&A: Black Holes

Q:
If two objects were drifting towards a black hole at the same speed and distance from the black hole, if they had different masses would the heavier one get "pulled" in first?

A:
This is a trick question. First, I assume you mean they are on radial orbits. The newtonian answer is that the more massive object goes in first (the black hole is attracted towards it more). Viewed from infinity, it takes infinite time for an object to cross the event horizon. So, technically, the General Relativity answer is that neither ever falls in. The Newtonian answer will still be correct (to the extent that it makes sense) in the General Relativity case, but off the top of my head I do not know what happens when they get close to the event horizon. The effective horizon will be a little larger for the more massive object, so I would be surprised if it does not stay ahead of the lower mass object (in effect). Of course, if the two are together (so they can influence one another) things can get very messy (they could orbit one another). Even if they don't, the less massive object would gain from the effect of the other object in moving the black hole.

Back | Index | Next