Reading Astronomy News: Giant Radio Telescope in China Just Detected Repeating Signals from Across Space
By Stacy Palen
Fast radio bursts have been known since 2007. Recently, China’s FAST telescope has detected a repeat of one first discovered at Areceibo in 2012. This article poses several explanations for fast radio bursts.
1) Study the picture of the 500-m telescope at the top of the article. Is this a “steerable telescope?"
Answer: No, this telescope is far too large to be steerable.
2) Describe how a telescope that is not steerable “sees” the sky differently than a steerable telescope.
Answer: A telescope like this can see only the portion of the sky that passes through its zenith. Because it is not steerable, it cannot track an object, so the observing time is set by the amount of time it takes for the object to pass through the field of view.
3) The signal was emitted from a source 3 billion light-years away. How long has the signal been travelling to reach us?
Answer: The signal has been traveling for three billion years.
4) What was happening on Earth when this signal left the source?
Answer: The earliest forms of photosynthesis date from around this time.
5) Why is a repeating FRB so interesting to astronomers?
Answer: If the FRB repeats, that rules out a whole class of causes. The object has clearly not blown up, so this is not connected to supernovae or black hole mergers.
6) Choose one of the proposed explanations for FRBs and explain in more detail how an FRB could be caused in that way.
Answer: Answers will vary.