HOW BIG IS OUR UNIVERSE
https://en.m.wikipedia.org/wiki/Universe
Our brains battle to know how large the universe is because the entirety right here on Earth, and even the Earth itself, is very small compared to the enormous scale of the universe. Let's assume about it a unique way, the usage of something we see and interact with everyday light.
While we think about mild to be instantaneous, photons of mild without doubt take time to journey from one facet of the room to the other. In the time it took you to examine this far, a photon of mild leaving the Sun has traveled about 10 million kilometers – equal to touring around the Earth 250 times.
The light that leaves our 2d nearest star, Proxima Centauri, takes simply over four years to attain Earth and so we can outline it as four mild years away. As such, if you had been to seem to be at Proxima Centauri, you would now not be seeing the celebrity as it is proper now, however, how it 'was' four years ago!
We see all matters in the universe as they had been in the past, whether or not they're on the different facet of the room or the different aspects of the galaxy. To take this thinking further, the nearest giant galaxy to us is Andromeda, which is so massive and shut that you can see it in the night time sky with your bare eye.
What you are, without a doubt, seeing is 1,000's of billions of stars in a configuration comparable to our Milky Way. However, all of these stars are about 2.5 million mild years away, which skill you are seeing Andromeda as it used to be 2.5 million years ago. The complete universe is littered with galaxies simply like the Milky Way and Andromeda, and the use of the most effective telescopes, we can see mild from galaxies that have taken greater than thirteen billion years to attain us!
Since a photon of mild left one of these galaxies, existence sparked into existence and evolved. Dinosaurs dominated the Earth. Humans appeared, developed tools, art, science, and technology, constructed the Hubble Space Telescope, put it into orbit, and subsequently stopped that bad photon on its thirteen billion 12 months journey! The universe is about 13.8 billion years old, so any mild we see has to have been journeying for 13.8 billion years or much less – we name this the 'observable universe.'
However, the distance to the side of the observable universe is about forty-six billion mild years due to the fact the universe is increasing all of the time. Imagine that a photon of mild is emitted from a factor on the aspect of our observable universe. While that photon has been traveling thru space, the universe has expanded. We have moved away from the factor the place the mild was once emitted, and it has moved away from us!
Though the mild would possibly have solely traveled for 13.8 billion years, the distance from us to the factor it got here from is, at present, forty-six billion mild years! So how huge is our universe? Well, we do not virtually know. However, it is big. So massive that even mild hasn't had time to go it in almost 14 billion years! And it is nonetheless getting larger all of the time.
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