In the last post about telescopes, “Telescope: how it works”, we explained their origins, how they work, and why we use them. We also explained that the design had a major flaw. It was designed to use light to see far away but if something is in the way, like our atmosphere, then the image gets blurry. That is why a telescope was launched into space, so it could see beyond our atmosphere. The name of that telescope is the Hubble Telescope.
Where is the Hubble Telescope?
The easiest answer to that question is it is 250 miles from the planet’s surface, but that doesn’t really give you a picture of its location. The atmosphere is divided into layers based on what is in them and how much gravity pulls on them.
- Closest to the planet is the layer of the atmosphere called the troposphere and is only 12 miles high, but it contains nearly all of our weather.
- The layer that is the furthest away is the exosphere and it begins at 440 miles high, but continues to spread for roughly another 5000 miles.
- The layer below the exosphere is where Hubble is located. It is the Thermosphere which ranges from 50 miles above Earth to about 450 miles.
The Thermosphere is special because it is where the parts of the atmosphere that mess with telescopes ends, but not gravity. There is no water, not even in vapor form, and even the few molecules in the air are spread roughly a mile from each other. However, the movement of these molecules can be seen the lowest parts of the layer in the phenomena we call the Aurora Borealis. Hubble, along with the international space station, orbit the Earth a few miles above that interference.
How is the Hubble Telescope used to look into space?
To explain that, a quick explanation about how light in space works is going to be needed. Light, like everything else, takes time to travel. It is really, really fast so we don’t usually think about light taking time to travel, but the further away from the source of light, the easier it is to imagine it.
For example, light from the sun takes 8 minutes to get to your eyes and the sun is just under 93 million miles away, but don’t get caught up in the distance yet. Remember, anything that happens on the sun, we won’t see until 8 minutes later. With that in mind, what about things further away than the sun, like 10 hours, days, or years? Now we are talking about a light year. A light year is the distance light travels in one Earth year. That distance is almost 6 trillion, that’s 6,000,000,000,000, miles. That’s a long distance, so here is where it gets difficult.
If you were able to see things that happened so many miles away, then you would be able to see what happened that long ago… in the past. That also means, the further you can see, the further back into the past you could see. Now this isn’t a time machine, it is simply something that already happened, like a sun burst from another star that throws light into space. That light is traveling toward Earth, but it is so far away that it has not arrived yet and we have a telescope to see it coming, just like sailors used those tubes with lenses to identify distant specks on the horizon as ships on the ocean.
What does the Hubble Telescope “see”?
Most of the general population think that Hubble just takes pretty pictures and then scientists analyze the pictures. In reality, Hubble analyzes space and takes a picture for scientists to see what it found. When the telescope is pointed in a direction it covers a field of view and within the field of view are different specks of light. To us they all look like stars, but to Hubble they have different colors, sizes, shapes, and even movements. Using Hubble, each speck of light is a discovery of a new mixture of molecules and compounds. Those mixtures create different wavelengths of light that could look like colors or could be undetectable to our eyes because they are moving too fast or too slow.
Either way, Hubble can detect the light and analyze it to some degree, but times have changed. Even with the 5 missions to upgrade Hubble, each making the telescope better and better, eventually, like anything else we’ve made, a newer, more technologically advanced model was going to be created. After over 25 years in the sky, “the next generation”, its original name, has almost been completed and the capabilities of this new telescope are incredible.
Tune in next time to discover the amazing new telescope, what it can do, what it can find, and where it will take us!