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

Author Question: Explain how we can estimate that there are about 50-100 billion galaxies in the observable universe. ... (Read 34 times)

justinmsk

  • Hero Member
  • *****
  • Posts: 524
on: Jul 27, 2018
Explain how we can estimate that there are about 50-100 billion galaxies in the observable universe.
 
  What will be an ideal response?

Question 2

Which statement is true of Venus' surface?
 
  A) There are no shield volcanoes.
  B) Atmospheric pressure is very low.
  C) It has remained unchanged for billions of years.
  D) There is an extensive hydrosphere.
  E) There are two continent sized uplands.


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

yahahah24021

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

While it's impossible to count so many galaxies one by one, we can observe a small part of the sky in detail and then extrapolate to get the total number. As an example, the Hubble deep field shows thousands of galaxies in a very small angular patch in 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.

Answer to Question 2

C


justinmsk

  • Member
  • Posts: 524
Reply 2 on: Jul 27, 2018
YES! Correct, THANKS for helping me on my review

Liamb2179

  • Member
  • Posts: 365
Reply 3 on: Yesterday
:D TYSM

« previous next »
 

Did you know?

Though the United States has largely rejected the metric system, it is used for currency, as in 100 pennies = 1 dollar. Previously, the British currency system was used, with measurements such as 12 pence to the shilling, and 20 shillings to the pound.

Did you know?

GI conditions that will keep you out of the U.S. armed services include ulcers, varices, fistulas, esophagitis, gastritis, congenital abnormalities, inflammatory bowel disease, enteritis, colitis, proctitis, duodenal diverticula, malabsorption syndromes, hepatitis, cirrhosis, cysts, abscesses, pancreatitis, polyps, certain hemorrhoids, splenomegaly, hernias, recent abdominal surgery, GI bypass or stomach stapling, and artificial GI openings.

Did you know?

Before a vaccine is licensed in the USA, the Food and Drug Administration (FDA) reviews it for safety and effectiveness. The CDC then reviews all studies again, as well as the American Academy of Pediatrics and the American Academy of Family Physicians. Every lot of vaccine is tested before administration to the public, and the FDA regularly inspects vaccine manufacturers' facilities.

Did you know?

Warfarin was developed as a consequence of the study of a strange bleeding disorder that suddenly occurred in cattle on the northern prairies of the United States in the early 1900s.

Did you know?

Acute bronchitis is an inflammation of the breathing tubes (bronchi), which causes increased mucus production and other changes. It is usually caused by bacteria or viruses, can be serious in people who have pulmonary or cardiac diseases, and can lead to pneumonia.

Barred Spiral Galaxies Barred Spiral Galaxies
Galaxies with Rings Galaxies with Rings
Big Picture of the Evolution of the Universe Big Picture of the Evolution of the Universe
An Estimate of the Time of Global Peak Conventional Oil Production An Estimate of the Time of Global Peak Conventional Oil Production
Diego Rivera, Man, Controller of the Universe. Diego Rivera, Man, Controller of the Universe.
Galaxies Galaxies
Video: Tuberculosis Testing

For a complete list of videos, visit our video library