We can only take pictures of
While astronomers cannot see actual past incarnations of the Milky Way, Hubble lets them see far distant, fundamentally similar galaxies, representing the Milky Way's appearance at different moments in time. A word about seeing into the past: Light takes time to travel.
One such estimate says that there are between 100 and 200 billion galaxies in the observable universe. Other astronomers have tried to estimate the number of 'missed' galaxies in previous studies and come up with a total number of 2 trillion galaxies in the universe.
The Milky Way (our galaxy) is approximately 100,000 light years across, so it has a radius of 50,000 light years. The Sun is not at the center of the galaxy, but is about 26,000 light years from the center. Now for your question: No, No man-made spacecraft has even left our solar system.
The technology required to travel between galaxies is far beyond humanity's present capabilities, and currently only the subject of speculation, hypothesis, and science fiction. However, theoretically speaking, there is nothing to conclusively indicate that intergalactic travel is impossible.
For most space objects, we use light-years to describe their distance. A light-year is the distance light travels in one Earth year. One light-year is about 6 trillion miles (9 trillion km). That is a 6 with 12 zeros behind it!
The trite answer is that both space and time were created at the big bang about 14 billion years ago, so there is nothing beyond the universe. However, much of the universe exists beyond the observable universe, which is maybe about 90 billion light years across.
Because space isn't curved they will never meet or drift away from each other. A flat universe could be infinite: imagine a 2D piece of paper that stretches out forever. But it could also be finite: imagine taking a piece of paper, making a cylinder and joining the ends to make a torus (doughnut) shape.
We currently have no evidence that multiverses exists, and everything we can see suggests there is just one universe — our own.
Using our knowledge of the death rate in the entire Milky Way, the death rate for visible stars works out at about one star every 10,000 years or so. Given that all those stars are closer than 4,000 light-years, it is unlikely – though not impossible – that any of them are already dead.
We can see light from 13.8 billion years ago, although it is not star light – there were no stars then. The furthest light we can see is the cosmic microwave background (CMB), which is the light left over from the Big Bang, forming at just 380,000 years after our cosmic birth.
The time it takes for light from objects in space to reach Earth means that when we look at planets, stars and galaxies, we're actually peering back in time.
Even though certain features of the universe seem to require the existence of a multiverse, nothing has been directly observed that suggests it actually exists. So far, the evidence supporting the idea of a multiverse is purely theoretical, and in some cases, philosophical.
The world as we know it has three dimensions of space—length, width and depth—and one dimension of time. But there's the mind-bending possibility that many more dimensions exist out there. According to string theory, one of the leading physics model of the last half century, the universe operates with 10 dimensions.
As it stands, the universe is the largest object that we are aware of. There is nothing larger, and everything we can smell, hear, taste, touch, or see is a part of it.
Scientists now consider it unlikely the universe has an end – a region where the galaxies stop or where there would be a barrier of some kind marking the end of space.
In about 100 trillion years, the last light will go out. The bad news is that the universe is going to die a slow, aching, miserable death. The good news is that we won't be around to see it.
Short answer: We don't really know how the universe was created, though most astrophysicists believe it started with the Big Bang. We know that we live in an expanding universe. That means the entire universe is getting bigger with every passing day.
One thing's for sure: the Universe does not have an edge. There's no physical boundary – no wall, no border, no fence around the edges of the cosmos. This doesn't necessarily mean that the Universe is infinitely large though.
Trillions of years in the future, long after Earth is destroyed, the universe will drift apart until galaxy and star formation ceases. Slowly, stars will fizzle out, turning night skies black. All lingering matter will be gobbled up by black holes until there's nothing left.
The average temperature of the universe is downright cold – right around 3 degrees above absolute zero. In order to measure the temperature deep space there must be a substance, because this is how we define temperature.
Observations from the ground and from space have confirmed thousands of planets beyond our solar system. Our galaxy likely holds trillions. But so far, we have no evidence of life beyond Earth.
So will it ever be possible for us to travel at light speed? Based on our current understanding of physics and the limits of the natural world, the answer, sadly, is no.
So the furthest out we can see is about 46.5 billion light years away, which is crazy, but it also means you can look back into the past and try to figure out how the universe formed, which again, is what cosmologists do.
Therefore, our universe is called the cosmos.