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 94 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?

There used to be a metric calendar, as well as metric clocks. The metric calendar, or "French Republican Calendar" divided the year into 12 months, but each month was divided into three 10-day weeks. Each day had 10 decimal hours. Each hour had 100 decimal minutes. Due to lack of popularity, the metric clocks and calendars were ended in 1795, three years after they had been first marketed.

Did you know?

Hypertension is a silent killer because it is deadly and has no significant early symptoms. The danger from hypertension is the extra load on the heart, which can lead to hypertensive heart disease and kidney damage. This occurs without any major symptoms until the high blood pressure becomes extreme. Regular blood pressure checks are an important method of catching hypertension before it can kill you.

Did you know?

All adverse reactions are commonly charted in red ink in the patient's record and usually are noted on the front of the chart. Failure to follow correct documentation procedures may result in malpractice lawsuits.

Did you know?

Every flu season is different, and even healthy people can get extremely sick from the flu, as well as spread it to others. The flu season can begin as early as October and last as late as May. Every person over six months of age should get an annual flu vaccine. The vaccine cannot cause you to get influenza, but in some seasons, may not be completely able to prevent you from acquiring influenza due to changes in causative viruses. The viruses in the flu shot are killed—there is no way they can give you the flu. Minor side effects include soreness, redness, or swelling where the shot was given. It is possible to develop a slight fever, and body aches, but these are simply signs that the body is responding to the vaccine and making itself ready to fight off the influenza virus should you come in contact with it.

Did you know?

HIV testing reach is still limited. An estimated 40% of people with HIV (more than 14 million) remain undiagnosed and do not know their infection status.

Global view of Mars as seen by the Viking 1 orbiter in 1980, showing the Valles Marineris (center) Global view of Mars as seen by the Viking 1 orbiter in 1980, showing the Valles Marineris (center)
Views of the Milky Way’s Central Regions Views of the Milky Way’s Central Regions
The Kaaba, center of the Haram Mosque, Mecca, Saudi Arabia. The Kaaba, center of the Haram Mosque, Mecca, Saudi Arabia.
Start the diagnosis by locating the relay center. It is under the hood on this General Motors ... Start the diagnosis by locating the relay center. It is under the hood on this General Motors ...
TV-Watching and Hyperactivity in Youth TV-Watching and Hyperactivity in Youth
The X-inactivation center (XIC) The X-inactivation center (XIC)
Video: Gas exchange - driving force

For a complete list of videos, visit our video library