## What would happen if you put a mirror in space?

Hannah – If we could magically put a mirror a million light years away in space then, in theory, if we were able to reflect an image of the Earth that we could see back on Earth, the light would have left the Earth two million years ago. Hannah – The size of the mirror that we would need would be absolutely huge.

### How can we look back in time with a telescope?

Because light takes time to travel from one place to another, we see objects not as they are now but as they were at the time when they released the light that has traveled across the universe to us. Astronomers can therefore look farther back through time by studying progressively more-distant objects.

READ ALSO:   Why are baseball games played during the day?

#### Can you see Earth’s past from space?

You don’t have to travel to space faster than light to see the Earth in the past. All you need to do is travel to a vantage point in space, e.g. ISS and you will see the Earth in the past.

How do astronomers find out how far away a star is?

By measuring the apparent position of a star at one point of the year and comparing it to its position at another point six months later, when the Earth is on the opposite side of the sun, astronomers can figure out how far away the star is. Astronomers call this technique stellar parallax.

How far away are we looking into the past?

Because of the finite speed of light, when you gaze up into the night sky, you are looking into the past. The bright star Sirius is 8.6 light years away. That means the light hitting your eye tonight has been traveling for 8.6 years.

READ ALSO:   Were there Samurais in ww2?

## How far away are the Stars of the Big Dipper?

The stars of the Big Dipper range from 60 to 125 light years away. When you look at Dubhe, the front star in the “bowl” of the Dipper, you are seeing light from before you were born. [Here’s a fun way to think about it.

### How many star systems are closest to the Sun?

Using NASA and other scientific sources, Stacker compiled a list of the 50 star systems closest to our sun. Explore these systems to learn what they can reveal about the universe and which ones might provide the right conditions for habitable planets.