Good morning ladies and gentlemen and welcome back to space facts by Tim. I am so in love with the unknown. Space is the king of the unknown. Truth be told we have explored more of Outer space than our own oceans. But percentage wise the numbers are far different. We have no idea how big space is leading theoretical physicists to assume we have only explored roughly less than .00001% of the known universe. That is almost nothing. Until a few centuries ago people thought stars were part of something called a firmament and were stationary. They had no clue the sun was a star. Fast forward 200 years and we have learned a lot.
We learned that the Earth is in fact a sphere.
We learned that the Earth is not the center of the universe. (Its not even the center of the galaxy.)
We have learned that the moon likely crashed into Earth billions of years ago and could possibly be a big factor in how water got to the Earth.
We learned that there are more stars in the universe than grains of sand on the entire planet Earth. (literalli Trillions of Trillions. Numbers so big we cant fathom them as the human mind is not capable of grasping numbers this big)
We learned that the universe is approximately 14 billion years old (minimum) we know this because the farthest light we can see is approximately that far from us. Does that mean the universe is definitely 14 billion years old? Not really. We just use the data we have to make assumptions. Just because light from 14 billion ly away (ly = light years) that is the age of the universe. But truth be told the universe is supposedly expanding faster than light speed. Which means the universe is likely far older than they suspect. I am just guessing from my limited knowledge in this field. But the universe could be 14 billion years old. Or it could be far older. This may be the 2nd universe (if you believe in the big bang/big crunch theory) This theory basically states that the universe exploded from a single point of infinite mass and energy *basically every single piece of matter and anti matter and energy was balled up into this singularity similar to a black hole (the best comparison I can come up with) Eventually this singularity becomes unstable and explodes. This explosion occurred over 14 billion years ago according to leading scientists. The explosion that happened 14 billion years ago was so massive the explosion is still going. Expansion is still doing its thing. Scientists theorize that eventually gravity from all the matter in the universe will win and the explosion will reverse causing all matter to eventually coalesce back into a signularity once again perhaps eventually triggering another big bang...
Most stars are not single entities floating around by themselves. Most start have a partner that they revolve around. In fact our Sun is a unique star. The conditions on Earth happened to be prime to support life. While life is likely not common across the universe I definitely believe in aliens and there is likely multiple different species inhabiting planets across the universe. We will likely never ever see these other species though unfortunately. Physics is universal. Even if they were super advanced traveling at light speed lets say. The closest star to us besides the Sun is Proxima Centauri and it is roughly 4 light years away. most stars are nowhere near that close. Just travelling across the milky way *(the galaxy we call home) is about 1,000,000,000,000,000,000 km (about 100,000 light years or about 30 kpc) across. That is a big number. Lets just say we sent a group of people in an airship that goes light speed. This is just theoretical but just imagine it were so. If every generation lived 70 years and died after 70 and produced off spring with some careful planning it would take 1428 generations of people having kids on a space ship just to make it across the milky way. We have no clue how abundant life is across the universe. For all we know we may be the only intelligent life in the milky way. (I think there is more life across the universe than people think... But intelligent life may be more rare than your typical animal like thought process creature that only thinks about eating and reproducing. This is all really just thoughts. We may never ever meet another intelligent species. We may be wiped out far before even a radio message were to arrive. Perhaps there is an intelligent species that knows we are here. Lets say they are 200,000 light years away. If they sent the message 1000 years ago we still have to wait 199,000 more years to receive that message. If a message sent a light speed takes that long think about a space ship. We always use ships that can travel light speed in these hypothetical scenarios but according to physics that is impossible. When matter travels at light speed it is converted to energy as matter with mass cannot travel at light speed. The only objects in the universe that can travel light speed do not have mass.
We learned that Even traveling the fastest we could travel (voyager space craft) If we left the Earth in the 1970s just trying to escape the solar system we would have just reached the oort cloud which is a theoretical cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from 2,000 to 200,000 au (0.03 to 3.2 light-years). That range is ridiculous. The oort cloud could be over 3 light years wide. Incredible. If we did leave the Earth at the same speed that Voyager got to while exploring planets through our solar system even after nearly 40 years of nonstop traveling at a speed of about 17 kilometers per second (38,000 mph) we still would be in the solar system and likely may not even be 1/2 way out. if it takes us over 40 years to even escape the solar system innerstellar travel is highly unlikely.
We know that there is water all over the place. Scientists used to think Water was not abundant. Turns out water is all over the place. Mars has water. Most of which is at the poles. Just the other day we figured out the moon has water as well. I am going to go out on a limb and say I think water is pretty common through the universe.
I will come up with more cool facts to share, Im going to end these here as I am at work. But I will start sharing more. I took a break but Im attempting to get back into the mix. I hope you enjoyed the facts!