Neutron Stars & Black Holes

Flashcards covering key concepts related to neutron stars, pulsars, gamma-ray bursts, and black holes.

What is left after a Type I supernova?

Nothing, just remains.

What can be left after a Type II supernova?

A neutron star or a black hole.

What type of pressure supports a neutron star?

Neutron degeneracy pressure.

What are two properties that young neutron stars have?

Fast rotation and strong magnetic fields.

What is a pulsar?

A highly magnetized rotating neutron star that emits beams of electromagnetic radiation.

Who discovered the first pulsar, and when?

Jocelyn Bell Burnell in 1967.

Describe the lighthouse effect.

It explains why we see pulsars appear to flash on and off as their beams sweep past Earth.

What happens to the energy pulsars radiate after a few tens of millions of years?

The energy output decreases then leading to a stop.

Pulsars will not be visible to us on Earth if their __ are not pointing our way.

Beams.

All ____ are neutron stars, but not all _____ are ______ .

Pulsars; neutron stars; pulsars.

What are gamma-ray bursts?

Intense flashes of gamma-ray radiation from distant space. (Lasting few seconds)

How were gamma-ray bursts first discovered?

By military satellites designed to detect nuclear bomb tests.

How do we know gamma-ray bursts must originate from outside our Galaxy?

Because their distances are too great to be from within the Milky Way.

Over what range of time does a typical gamma-ray burst last?

A few milliseconds to several minutes.

What must we usually study to determine the distance to a gamma-ray burst?

The afterglow of the burst.

What are the two possible ways gamma-ray bursts are believed to be created?

Merger of neutron stars and collapse of massive stars (Hyper Nova)

What is the minimum mass of a progenitor star to form a black hole during its death?

About 20 and 30 solar masses.

The radius at which the escape speed from the black hole equals the speed of light is called what?

The Schwarzschild radius.

What is a black hole’s event horizon?

The boundary beyond which nothing can escape from a black hole.

Which of the following can escape from inside a black hole’s event horizon? A. Neutrinos B. Electrons C. High energy gamma-ray bursts D. Gravitons E. None of the listed choices

E. None of the listed choices.