This topic contains a solution. Click here to go to the answer
« previous next »

Author Question: If they existed, and if they were watching, a civilization at the center of the Milky Way could have ... (Read 41 times)

ghost!

  • Hero Member
  • *****
  • Posts: 560
on: Jul 27, 2018
If they existed, and if they were watching, a civilization at the center of the Milky Way could have detected our first TV signals by now.
 
  Indicate whether the statement is true or false

Question 2

Explain how we estimate that there are about 50-100 billion galaxies in the observable universe.
 
  What will be an ideal response?


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

tandmlomax84

  • Sr. Member
  • ****
  • Posts: 323
Reply #1 on: Jul 27, 2018
Answer to Question 1

FALSE

Answer to Question 2

Obviously it's impossible to count so many galaxies one by one, but by observing a small part in detail, we can extrapolate to get the total number. As an example, the Hubble deep field shows thousands of galaxies in a very small angular area of the sky (about equal to the size of a grain of sand held at arm's length). Multiplying the number of galaxies by the ratio of the angular area of the entire sky to the angular area of the deep field then gives an estimate of the total number of galaxies in the observable universe.


ghost!

  • Hero Member
  • *****
  • Posts: 560
Reply #2 on: Jul 27, 2018
Thank you!


tandmlomax84

  • Sr. Member
  • ****
  • Posts: 323
Reply #3 on: Jul 27, 2018
Always glad to help...


« previous next »
 

Did you know?

Drug abusers experience the following scenario: The pleasure given by their drug (or drugs) of choice is so strong that it is difficult to eradicate even after years of staying away from the substances involved. Certain triggers may cause a drug abuser to relapse. Research shows that long-term drug abuse results in significant changes in brain function that persist long after an individual stops using drugs. It is most important to realize that the same is true of not just illegal substances but alcohol and tobacco as well.

Did you know?

Intradermal injections are somewhat difficult to correctly administer because the skin layers are so thin that it is easy to accidentally punch through to the deeper subcutaneous layer.

Did you know?

The eye muscles are the most active muscles in the whole body. The external muscles that move the eyes are the strongest muscles in the human body for the job they have to do. They are 100 times more powerful than they need to be.

Did you know?

Asthma is the most common chronic childhood disease in the world. Most children who develop asthma have symptoms before they are 5 years old.

Did you know?

Russia has the highest death rate from cardiovascular disease followed by the Ukraine, Romania, Hungary, and Poland.

Off-Center Disk Off-Center Disk
Spiral Galaxies Seen Nearly Edge On from the Milky Way Spiral Galaxies Seen Nearly Edge On from the Milky Way
Milky Way Milky Way
Do you know what that large object in the center of the photo is? In the 1920s, 30s, and 40s, ... Do you know what that large object in the center of the photo is? In the 1920s, 30s, and 40s, ...
Ti Watching A Hippopotamus Hunt Ti Watching A Hippopotamus Hunt
TV-Watching and Hyperactivity in Youth TV-Watching and Hyperactivity in Youth
Video: Subunits of DNA And Semi Conservative Replication

For a complete list of videos, visit our video library