3.Which of the following is evidence of a near-Earth supernova having occurred 2

Question

3.Which of the following is evidence of a near-Earth supernova having occurred 2.8 million years ago?

Select one:

A. Cave paintings of the intensely bright event by early humans

B. Cosmic ray particles embedded in ancient ice cores

C. A spike in the abundance of radioactive iron in rocks of that age

6.

Why is the star IK Pegasi not a threat to life on Earth?

Select one:

a. The Sun-like star in IK Pegasi is still fusing hydrogen. It will be at 1-2 billion years before it evolves into a red giant, allowing the white dwarf to capture mass and exceed the 1.4 MSun mass limit.

b. IK Pegasi is a binary system with a white dwarf and a Sun-like star. Only massive stars explode in supernovas.

c. IK Pegasi is too far from Earth to be a threat to life.

Explanation / Answer

3. C. A spike in the abundance of radioactive iron in rocks of that age

6. c. IK Pegasi is too far from Earth to be a threat to life.

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