NASA | A Flickering X-ray Candle

The Crab Nebula, once considered a steady beacon for X-ray astronomers, has shown unexpected variations in brightness. Observations from 1999 to 2008 revealed fluctuations, and since 2008, a decline in brightness was detected by NASA's Fermi satellite, which also observed gamma ray flares. Scientists believe these changes are due to processes within the nebula's core, powered by a rapidly spinning neutron star. Future research with advanced X-ray telescopes is needed to understand these long-term changes.

What is the Crab Nebula primarily known for among X-ray astronomers?

• Its rapid movement across the sky

• Its brightness and steadiness

• Its proximity to Earth

• Its unusual color

What did NASA's Fermi satellite detect about the Crab Nebula?

• A decrease in its size

• A change in its color

• A decline in its X-ray emissions and gamma-ray flares

• An increase in its distance from Earth

What powers the processes deep within the Crab Nebula?

• A black hole

• A massive asteroid

• A supernova explosion

• A rapidly spinning neutron star

What does the image from NASA's Chandra X-Ray Observatory reveal about the Crab Nebula?

• Its outer shell is expanding

• It is losing mass rapidly

• Its inner region is complex

• It is moving towards the Milky Way

What is required to understand the long-term X-ray changes in the Crab Nebula?

• Larger optical telescopes

• Advanced infrared sensors

• More powerful radio telescopes

• A new generation of hard X-ray telescopes