For those not that keen about our stars. The couple ones we see on our hemisphere (about 2000 each side) are a handful stars in the Orion wing around us out of millions. Orion is one of a handful wings of spiral Galaxy milkyway which has an estimate of billions of stars. In the center of Milkyway is a black hole, sucking us once down. The more is swallows, the bigger gravitation it gets, the faster it goes. Well it will last a couple years until it happens.
Our next star being 4 light years away (1.3 Parsec) is called Proxima Centauri. The next bigger Galaxy is called Andromeda. A couple of those Galaxies then are called a cluster, our cluster is called The Local. Next bigger unit is called a constellation having itself again Billions of Galaxies, each Galaxy having Billions of stars.
There are different classes of stars. Some are bigger than our sun, called red giants, the bigger they are, the more red they shine, the coolor they are on surface. Well, our sun has a core temperature of 100 million degrees. The principle of suns is core fusion where Hydrogen converts into Helium, a principle they want actually to copy at Max Planck institute in Munich. Once you get such a sun running, you take unlimited energy out. The problem just is, to get this reation to work as you first need to start it with an amount of energy being in a dimension of what a nulcear power plant is delivering. And afterwards it runs, the headache is about how to handle those temperatures not to let them melt everything what is around.
Smaller suns than our one are called white dwarfs, they are bright. Brighter means, such ones have higher temperatures. Some suns once in a liftime get unstable and finally blow up, what is called a Super Nova. It will once happen with our own sun when running out of hydrogen as far i know. Then you got all sort of differnt classes as all those objects are turning in differnt speeds of course. When Astronoms watch skies, they do not see planets turning around other suns. But an object circling around a sun, causes even a bigger sun to move in space with a certain frequency. That is what recently they found out about and now can measure those moves and frequency to say if there are any planets around those suns. Likely with James Webb then, they can watch other people eat pizzas on those discovered planets, but with Hubble yet you just see the suns.
Now you can maybe imagine, within those Billions of Billions of other suns, there must be at least one other planet as our one called earth, or did you really think out of such a flood of planet, earth was the only one having a civilization?
By the time we humans nearly do everything to destroy our own little planet, likely most of those big men are not really aware of there is no other place in space to run when we fulfilled our jobs. Technically, with all nuclear weapons, we are able to blow planet earth to small peaces into space. Very likely, this is going to happen with us. The American thrown nuclear kiloton bombs have been a furt considering what is available now with all Megaton bombs. Even we not once manage to blow our planet apart when such called Trump or any other pricks once press trigers, we would not survive radioactive contamination. But even then in evolution, this planet does not really need us and once we made it work to kill ourselves, earth will heal itself over another millions of years.
When understanding the dimension of universe now, did you really think earth is important? It is just another of billions of planets having a civilization highly likely. And if we blow ourselves up here, no one other will care much about.
Of course there are Aliens. Some will have a less, but many will have a more advanteced technology than us. As you know, our computers came up with NASA in the 60s what is actually just 50 years ago in an evolution of universe being 5 billion years old. Now do you hesitate to believe, there must be others having the ideas of computers a couple thousand or even million years before us?
Most having a more advanced technology than us likely would never want to get in touch with us humans, as we are by far not ready for it. At least as long they are not even more evil and selfish than us. All we are, self destroying primates still enlaving others, doing all sort of massacres forced by neverending stupidity, selfishness and arrogance. A failure in evolution we are. But once humans, if they make it not to blow their planet apart, will learn to do better. Such alien civilizations having an advanced technology to reach planet earth might have gone through similiar processes, likely they would never want to get in touch with us when seeing what we do. The funny part, we humans put billions of our paper Dollars into such projects to watch out for others. But what would we do with them if we met them? We would enslave and kill them, right. Same we actually do around earth by the time with millions of people around here already. You can call it funny, or silly. By all efforts, sending golden disks with human signatures into space to get in touch with others, we never have been able yet not to destroy what we got here.
Now our space telescopes discovered in the meantime about 1000 other planets in our Galaxy which are located in the, you call it Green Zone. Where live is possible. Just a bit too far from a sun it will be cold as hell, too close as on Venus, it will be a hell itself. The technology to find Green Zone planets has been developped by Swiss scientists.
Now you maybe thought those planets they find must be on other Galaxies as Andromeda. But to disappoint you, they are just seeing a couple ones around our corner in Orion wing of Milkyway. And not even those we once would reach in a thousand years. All we reached yet with robots was Mars. And even a trip to little Mars which is just a glimpse away from us would be life threatening for humans. Too small spacecrafts having no gravitiy, solar radiation etc. No way humans would make it to get away from our planet here, no matter what Elon Musk is talking about. The efforts to resist earth gravity by bringing materia into space are just too big. You need thousands of tons of fuels just to bring a little satellite into space. Once those rocket fuels burn out, there are not many options. Biggeset speed we reached in space was a couple thousand km per hour. Dimensions away from the speed we really needed to even reach our next star.
Some objects in space into our direction. Some of them hit earh. A 100m diameter object called Meteor will cause a devastation within a 1000km diameter. A 1km diameter Meteor impact on our planet will cause us a next ice age as it once happpened at Gulf of Mexico. As those object are barely visible in space, you see them in last second.
Hubble by the time can watch nearly to the end of our Universe, next upcoming satellite called James Webb then likely will find out about our Universe is just another of a Billion other universes.
With all knowledge we now got on earth and the equation of Einstein, we would never bee able to even reach our next planet Proxima Centauri. The formula says: If you want to travel with light speed, you would need unfinite energy. That is why now Elon Musk concentrates to stay within our sunsystem and gives us a colony on Mars first until we all got smarter again. But maybe first at all we should solve once the couple issues on this planet first before letting our emperors colonize space. 30 million refugees seem to be reason enough?
There are different kind of Telescopes. Some are watching in the spectrum of visible light, Infrared or Ultraviolet (nanometer frequencies), another ones are in the millimeter spectrum which are a bit bigger and some listen on radio frequencies which have then antennas a 10 meter diameter and more. The smaller those signals, often travelling for billions of years, the bigger dishes you need to catch them. That is why on La Palma island, they need to watch out street lights are not disturbing the observatories on top of the moountain.
Another observatory is for detecting Neutrinos. Those Neutrinos cross our planet as if it was nohting and it is hard to catch a couple. Those facilities are usually deep underground in any ancient mines. The best places with clear skies, no light emission disturbances of civilizations are Atacama desert and of course the Scott base in Antarctica.
By 2016 the Chinese built the biggest Radio telescope with a 500m diameter which is already operational by the time.
You remember when hubble needed glasses as its pictures were not sharp when first being switched on? This story was because of the mirror had a mistake of 0,002 millimeter.
So i will overgive this section to the real scientists on earth, hope we all get smart with our space and what to see more than a couple Billion nebulas, comets, big and small suns one looking like another.
Hope some will enjoy this section. I did it for my own happyness beside of usually daily following wars, nightmares and tragedies provided by all those mighty, powerful and primate humans and big men leading this planet from one war and insanity to another.