Time-Travelling through the telescope
By: Dashmi Wijerathna
Tags: NASA, Cosmology, Time Travel, Telescope, Freestyle

Scientists claim that if an alien 65 million light-years away, see the earth through a powerful telescope, they can see “dinosaurs”. Is it possible?

Did you know that when we look at objects in space through a telescope, we are looking at the past?

Celestial bodies like stars or faraway galaxies are far too distant to be measured in kilometers. Therefore, we use “light years”, which is a measure of the distance light travels in one year. Given how fast light travels, it takes less than a nanosecond to travel from the eyes to the TV or a wall, or even a house 200–300 meters away.

Sound travels one kilometer every three seconds, while light travels 300,000 kilometers per second. If we see a flash of light three kilometers away, and then seconds pass until we hear the rumble of distant thunder. What we see is what happened one-hundredth of a milliseconds ago, and what we hear happened seconds ago. That is not exactly the distant past.

If we were to look at our closest celestial bodies like the moon, which is 380,000 kilometers away. We see it as it was 1.3 seconds ago. Because it only takes 1.3 seconds for light to travel from the moon to us. If we look at the sun, we will see it as it was about 8 minutes ago.

The moon doesn’t change much from one moment to the next. But when the mission control center talks to the astronaut on the moon, this delay can be noticed. Radio waves travel at the speed of light, so it takes 1.3 seconds for information from the mission control center to reach the moon, and even the fastest response takes 1.3 seconds to return.

The Andromeda Galaxy is 2.5 million light-years away. It is the most distant celestial body visible to the naked eye. The light we see now has a history of 2.5 million years. The closest human relatives that could have seen the Andromeda Galaxy are the Genus Australopithecus.

So if we were to go back to when the dinosaurs went extinct, which is 65 million light-years away. We would find the NGC 4845 galaxy. Let’s assume some brilliant aliens residing there decided to look our way. If so, they’ll see the earth as it was at the time of the dinosaurs. But we cannot be certain that they would see any individual dinosaurs getting hit by an asteroid. Because they’ll need a very powerful telescope. Unless the aliens have technology that surpasses ours, the laws of physics make it impossible to make a telescope that powerful.

When it comes to our technology in recent years, the Hubble Space Telescope has obtained images of some galaxies that are seen in their early stages of development. To go further back to the time when the stars began to shine, we would need a telescope that can detect extremely low-intensity infrared light. Because although the light from these young stars in distant galaxies is emitted in the form of visible light, it has been stretched to resemble infrared light by the expansion of the universe.

It is hoped that when the James Webb Space Telescope is finally launched, we will be able to look back in time and observe events that occurred in distant galaxies a long time ago.

So the conclusion is until we can build a telescope that defies the laws of physics, we cannot be certain that aliens are peeping at our Mesozoic Era. But we are certain that we do not need a Tardis to time-travel. We can do that with just our bare eyes or with glasses, if you can’t see without them.

So when you look up, remember you aren’t seeing things as they are now, you’re seeing things as they were.