What is Sagittarius A*?

The supermassive black hole at our galaxy's center

How did astronomers prove a black hole was there?

By tracking stars orbiting an unseen mass

What is the Event Horizon Telescope?

A worldwide network of radio telescopes

What does the asterisk in the name refer to?

It marks it as an exciting radio source

Sagittarius A* Quiz: Star Orbits and Our Galaxy's Black Hole

This Sagittarius A* quiz peers through dust to the heart of the Milky Way. Play 10 interactive questions on its mass, its distance, the star S2, decades of tracking orbits, the 2020 Nobel Prize for Andrea Ghez and Reinhard Genzel, the 2022 Event Horizon Telescope image, gravitational redshift and what the asterisk means.

Start Sagittarius A* Quiz

🎯 Daily Trivia Challenge • 🧠 10 Questions • ⏱️ 150 Seconds

Question 1 / 10 Time: 150s

What
What is Sagittarius A*?
Mass
About how massive is Sagittarius A*?
Distance
About how far away is it?
S2
What is S2?
Proof
How did astronomers prove a black hole was there?
Nobel
Who shared the 2020 Nobel Prize for this work?
Image
When was the first image of Sagittarius A* released?
EHT
What is the Event Horizon Telescope?
Redshift
What did S2's 2018 close pass confirm?
Star
What does the asterisk in the name refer to?

Explanations: answer key for all 10 questions

Q1: What is Sagittarius A*?
Answer: The supermassive black hole at our galaxy's center
It is in the Milky Way.
Q2: About how massive is Sagittarius A*?
Answer: About 4 million Suns
It is huge but quiet.
Q3: About how far away is it?
Answer: About 26,000 light-years
Dust hides it from visible light.
Q4: What is S2?
Answer: A star that orbits close to it
Its orbit takes about 16 years.
Q5: How did astronomers prove a black hole was there?
Answer: By tracking stars orbiting an unseen mass
Only a black hole fit the data.
Q6: Who shared the 2020 Nobel Prize for this work?
Answer: Andrea Ghez and Reinhard Genzel
Roger Penrose shared the prize too.
Q7: When was the first image of Sagittarius A* released?
Answer: 2022
The Event Horizon Telescope made it.
Q8: What is the Event Horizon Telescope?
Answer: A worldwide network of radio telescopes
It acts like an Earth-sized dish.
Q9: What did S2's 2018 close pass confirm?
Answer: Gravitational redshift predicted by Einstein
Light stretched near the black hole.
Q10: What does the asterisk in the name refer to?
Answer: It marks it as an exciting radio source
Astronomer Robert Brown coined it.

Sagittarius A* Quiz – Star Orbits and Our Galaxy's Black Hole

Sagittarius A* is the supermassive black hole at the center of the Milky Way, about 26,000 light-years away. It has about 4 million times the mass of the Sun.

Teams led by Andrea Ghez and Reinhard Genzel tracked stars racing around an unseen mass for decades. The star S2 orbits every 16 years, and its 2018 close pass confirmed gravitational redshift predicted by Einstein.

Ghez and Genzel shared the 2020 Nobel Prize in Physics. In 2022 the Event Horizon Telescope, a worldwide network of radio dishes, released the first image of the black hole's glowing ring.

What This Quiz Teaches

Astronomy fans will enjoy these questions.

What Sagittarius A* is
How big and far it is
How it was found
Who won the Nobel
How it was imaged

Did You Know?

It is much quieter than many black holes in other galaxies.
Infrared light lets astronomers see through the dust.
Flares from it happen several times a day.
It lies in the direction of the constellation Sagittarius.
M87's black hole was imaged first, in 2019.