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

Author Question: Why are all spiral tracers young? What will be an ideal ... (Read 68 times)

magmichele12

  • Hero Member
  • *****
  • Posts: 559
on: Jul 27, 2018
Why are all spiral tracers young?
 
  What will be an ideal response?

Question 2

Most stars generate their energy by the thermonuclear fusion of ___________________ _ to form ___________________ _.
 
  Fill in the blank(s) with correct word


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

sierrahalpin

  • Sr. Member
  • ****
  • Posts: 329
Reply #1 on: Jul 27, 2018
Answer to Question 1

Spiral tracers are young objects, formed recently, astronomically speaking. O stars, for example, live for only a few million years. Their typical orbital velocity is about 200 km/s, so they cannot move more than about 500 pc in their lifetimes. This is less than the width of a spiral arm. Because they don't live long enough to move away from the spiral arms, they must have formed there.

Answer to Question 2

hydrogen; helium


magmichele12

  • Member
  • Posts: 559
Reply 2 on: Jul 27, 2018
Gracias!

bblaney

  • Member
  • Posts: 323
Reply 3 on: Yesterday
Great answer, keep it coming :)

« previous next »
 

Did you know?

Alzheimer's disease affects only about 10% of people older than 65 years of age. Most forms of decreased mental function and dementia are caused by disuse (letting the mind get lazy).

Did you know?

Many supplement containers do not even contain what their labels say. There are many documented reports of products containing much less, or more, that what is listed on their labels. They may also contain undisclosed prescription drugs and even contaminants.

Did you know?

The horizontal fraction bar was introduced by the Arabs.

Did you know?

There can actually be a 25-hour time difference between certain locations in the world. The International Date Line passes between the islands of Samoa and American Samoa. It is not a straight line, but "zig-zags" around various island chains. Therefore, Samoa and nearby islands have one date, while American Samoa and nearby islands are one day behind. Daylight saving time is used in some islands, but not in others—further shifting the hours out of sync with natural time.

Did you know?

Although not all of the following muscle groups are commonly used, intramuscular injections may be given into the abdominals, biceps, calves, deltoids, gluteals, laterals, pectorals, quadriceps, trapezoids, and triceps.

The Spiral The Spiral
Variety in Spiral Arms Variety in Spiral Arms
Why did these young volunteers of the First Virginia Militia join the Confederate army in 1861? “It Why did these young volunteers of the First Virginia Militia join the Confederate army in 1861? “It
Many households today include young adults who have not moved out of their parents’ homes (or who ... Many households today include young adults who have not moved out of their parents’ homes (or who ...
Because of immature visual-motor coordination, young children find it hard to throw and catch small ... Because of immature visual-motor coordination, young children find it hard to throw and catch small ...
Typical Night’s Sleep for a Young Adult Typical Night’s Sleep for a Young Adult
Video: Hip Animation

For a complete list of videos, visit our video library