How many galaxies?

How many galaxies?

​Kroo Moo-Noi

astronomer

faint

galaxy

solar system

telescope

torch

​Vocabulary

Imagine your town. Then your country. Then the Earth. Then our solar system.Then our galaxy....

​What is the name of our galaxy?

It's difficult to think about something as big as a galaxy, containing billions of stars. Our galaxy, called the Milky Way, measures 100,000 light years across. If you stood at one side of our galaxy and switched on a torch, it would take 100,000 years for its light to reach the other side!

​What is the name of our galaxy?

And the Milky Way is just one galaxy. For many years, scientists thought there were 200 billion galaxies, but in 2016 they realised they were wrong. We now know there are ten times more than that - around two trillion galaxies! We know that because of the Hubble Telescope. It was built by NASA and sent into space in 1990. The Hubble telescope sends photos from space back to the Earth, to help us understand our universe.

​What is the name of our galaxy?

We can't see the new galaxies that the telescope discovered. They are too far away. Astronomers used Hubble's photos to make 3D models, and when they did the maths, they understood that humans could not see most of the universe. Our technology is not strong enough yet.

​What is the name of our galaxy?

Christopher Conselice is one of the astronomers. He said "It boggles the mind that over 90 percent of the galaxies in the universe have yet to be studied. In the near future, the James Webb space Telescope will be able to study these ultra-faint galaxies." The James webb Space Telescope will replace the Hubble. It can see further and take better photographs.

​What is the name of our galaxy?

Imagine our galaxy. Then 200 billion galaxies. Then two trillion galaxies. What do you think the new telescope will find out there?