Questions for ‘How to catch a gravity wave’

crab nebula

This Crab Nebula is the aftermath of a supernova — the explosion of a dying star. At its center is a pulsar, a type of neutron star. Supernovas and pulsars are both potential sources of gravity waves — energy giving information about distant, violent events throughout the cosmos. 

NASA, ESA, J. Hester, A. Loll (ASU)

To accompany feature “How to catch a gravity wave”


Before Reading:

1.    Name three things that move, or spread, as waves.

2.    What is gravity and explain how it affects activities on Earth.

During Reading:

1.    What was the source of the gravity waves that were recorded for the first time in 2015?

2.    Who first predicted such waves would exist, and in what year?

3.    Radio waves are a type of what kind of radiation?

4.    How do gravity waves differ from radio waves in the way they travel?

5.    Who designed the first gravity-wave detector and what did he make it out of?

6.    Why is it important to have at least two detectors searching for gravity waves at the same time?

7.    What was one advantage of Weiss’s design for a gravity-wave detector, compared with Weber’s bars?

8.    What does LIGO stand for and where are its two detectors located?

9.    Name at least two other countries where detectors are hunting for gravity waves.

10.  According to the article, what types of information might gravity waves share with astronomers about distant objects?

After Reading:

1.    Most scientists think Weber was unsuccessful with his bar detector. If, in fact, he never found a gravity wave, would you consider his efforts a waste or not? Remember, science is a search for answers, not necessarily just the acquisition of answers. (Also: Consider Weiss’s observation about his own work.) And whatever you decide about Weber, explain how you came to your assessment.

2.    At least two nations have developed gravity-wave detectors in addition to the United States. At least two more nations are planning to build them. These are costly systems. If you were a researcher (or funding agency) in Japan, India or somewhere in Europe, how would you justify building your own gravity wave detectors? Give at least two arguments why your nation should do so. Now, give at least two arguments why it shouldn’t. Be specific.


1.    The first estimates of how much LIGO might cost to build was around $200 million. It eventually cost nearly $300 million. How much of an increase is that, in percent? If the agency that was going to pay for it had a budget of $418 million dollars, how much of its budget — by percent — would the original amount have been; and what percent share would a $300 million price tag equal?