Extreme Objects

Key facts

PSR B1919+21 – the first pulsar

This was the first pulsar ever found: a spinning neutron star that sweeps a beam of radio waves across Earth like a lighthouse. Its pulses are so regular that at first scientists wondered whether they were an alien signal.

Crab Pulsar

At the heart of the Crab Nebula is a neutron star only about 20 km across but heavier than the Sun. It spins about 30 times every second, blasting out beams of radiation that light up the whole nebula.

Vela Pulsar

The Vela Pulsar is the collapsed core of a star that exploded about 11,000 years ago. It is one of the brightest sources of gamma rays in the sky, and sometimes it suddenly spins a little faster – a “glitch”.

Cygnus X-1

Cygnus X-1 is a black hole pulling gas off a giant blue companion star. As the gas spirals in, it heats up to millions of degrees and glows in X-rays. It was the first object most astronomers agreed was a black hole.

Sagittarius A*

At the centre of our galaxy lies Sagittarius A* (say “A-star”), a supermassive black hole. Stars race around it in tight orbits, and by tracking them astronomers proved it’s there.

M87* – the first black hole photo

M87* is a gigantic black hole in the galaxy Messier 87. In 2019 it became the first black hole ever photographed: a dark shadow surrounded by a glowing ring of hot gas.

Quiz

1. Who discovered the first pulsar in 1967?

   • ☐ Albert Einstein
   • ☐ Jocelyn Bell Burnell
   • ☐ Stephen Hawking
   • ☐ Edwin Hubble

2. What is at the centre of our Milky Way galaxy?

   • ☐ A huge star
   • ☐ Nothing
   • ☐ A supermassive black hole
   • ☐ Another galaxy

3. When was the first-ever image of a black hole released?

   • ☐ 1969
   • ☐ 1999
   • ☐ 2019
   • ☐ It has never been photographed

Find it in the sky

Use the Sky Finder at seethestar.com. Tick what you find and write when you saw it.