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Q & A: Rotation of Earth with respect to center of the galaxy?

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Most recent answer: 08/25/2017
Q:
how fast the earth rotates relative to the black hole of center of the galaxy?
- Nicola (age 32)
Grontardo (cr) italy
A:
Ciao Nicola,

The Earth is pretty far out from the center of the galaxy which is in the constellation .   There is evidence that there is a big black hole there, named .  The rotation rate for our position in the Milky Way is about once per 200 million years.
As you can imagine, the galaxy is not a solid disk so rotational rates can vary as a function of distance to the center.  Observation and analysis of this phenomenon has provided evidence that there is a component of mass within the galaxy called dark matter.  It is a current hot topic in the astro-physics community.  Take a look at  for an interesting discussion.

LeeH



(published on 03/19/2013)

Follow-Up #1: missing links

Q:
Hello My question is....why do there appear to be missing words in your answer to this question? There appear to be two missing words in the first three sentences (marked with [??]): "...the galaxy which is in the constellation [??]. There is evidence that there is a big black hole there, named [??]. The rotation rate for..." It also happens in your answer to this question (https://van.physics.illinois.edu/qa/listing.php?id=1086&t=hypergiant-stars): "According to [??], hypergiant stars are..." I notice that this is quite common in other answers as well. Also, you often refer to a link which does not seem to appear. Is this related? Kind Regards Iain
- Iain (age 30)
London
A:

We were having problems with some sort of cyber attacks, and had to do some protective filtering of the site. In the process, unfortuantely many good url's were lost, seriously affecting the quality of many answers. You noticed one of them.

Mike W.


(published on 08/25/2017)

Follow-up on this answer.