Telescopes are often called time machines because they show us what has happened in the past. When we look at a star, we can see what it looked like years ago.
By looking through the Hubble Space telescope, astronomers have been able to study how galaxies evolve with time.
Telescopes also allow astronomers to see deep into space and back in time when stars were being born from gas and dust clouds that had been around since the Big Bang.
Some more information are discussed here about why are telescopes sometimes called “time machines”?
A telescope is a device that collects light. The word “telescope” comes from the Greek word for “farseeing”. Sometimes it is easy to confuse a telescope with a camera, but they are different devices.
A camera collects images, but the images are upside down and reversed. A picture taken with a camera can be converted into colors by adjusting an appropriate color filter or dye over the lens.
A real telescope projects patterns of light onto pictures on paper so it can be seen as colors right-side up and normal to us. A camera does not do this.
Here are some of the reasons are discussed about why telescopes are called time machine-
1. Telescope shows distant galaxies and stars across the Universe.
The farther and farther away we look in space, the faster the Universe is expanding. This means that when we look back into time, we see galaxies that are much farther away than they are now.
The Hubble Space Telescope was launched in 1990 to see how the Universe has changed over the past 20 years. It is still in orbit today.
2. Telescopes are able to see stars that are too dim to be seen with the naked eye.
The human eye can only see stars that are 1,000 times brighter than other visible light sources in the night sky, but using a telescope, we can look at places where there are 100 million times less light than other visible light sources in the night sky.
The less light there is around us, the farther away it comes from. Light travels at about 186,000 miles per second (300 000 km per sec).
We can measure this speed because light gets to us almost instantly, even if it travels through space for billions of years.
3. Telescopes show us what stars are made of.
Different stars have different levels of elements like hydrogen and oxygen in their atmospheres which we cannot see with our eyes at night.
There are thousands and thousands of stars in the sky and we really could not see all of them in the night sky if we were only looking at them at or near human eye visibility because there is so much light reflected off the moon, planets and other objects in the sky.
Different stars have different elements in their atmospheres which we can not see with our eyes at night.
4. Telescopes tell the time of day to the nearest minute, even if it is far away.
While there are many ways to keep track of the time, the way that shows us how long it has been since sunrise or sunset is as follows – as a clock goes around once every 24 hours, an observer on Earth sees the sun rise in the East and set in the West.
The time between sunrise and sunset can be measured from any location on Earth by carefully watching for a star that appears to drift up from behind a distant mountain or other object on Earth’s horizon as night begins and descends as day ends.
It can also be measured by carefully watching for a star that appears to drift up from behind the sun as sunrise or sunset begins and descend as night begins.
5. Telescopes can show us what some stars look like at night.
Stars are not only seen at night. They also emit some light during the day and we can use a telescope to see them during the day too.
A star such as the Sun is bright enough that we can’t see it directly with our eyes, but we can see it through a telescope.
Other stars like Sirius or Arcturus, on the other hand, are dim enough that we cannot see them unless they line up just right with our eyes and telescopes on Earth.
6. Telescopes show us the history of the Universe.
When astronomers look at distant galaxies with telescopes, they can see how they change over time. Galaxies are made of stars that are billions of years old and each one has its own unique birthmark on it that was made when it first formed.
The way these galaxies change over time is very important for scientists to understand how the Universe works on a grand scale.
