Why is the observable universe 93 billion light years across?
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Why is the observable universe 93 billion light years across?
That’s because over time, space has been expanding, so the distant objects that gave off that light 13.8 billion years ago have since moved even farther away from us. Multiply times 2, and you get 93 billion light years, the diameter of the observable universe.
How can the universe be bigger than 14 billion light years?
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Well, the answer is general relativity. The Universe can create as much space as it likes, even so much that it appears that distant objects are travelling faster than c.
How fast is a light year?
In a vacuum, light travels at 670,616,629 mph (1,079,252,849 km/h). To find the distance of a light-year, you multiply this speed by the number of hours in a year (8,766). The result: One light-year equals 5,878,625,370,000 miles (9.5 trillion km).
What happened in the Universe 13 billion years ago?
Something wonderful happened about 13.8 billion years ago. Everything in the universe was created in an instant as an infinitesimally small point of energy: the Big Bang. We know that this event happened, as the universe is constantly expanding and galaxies are moving away from us.
How far back in time can we see the universe?
Therefore, the longer we wait, the farther we can see, as light travels in a straight line at the speed of light. So after 13.8 billion years, you’d expect to be able to see back almost 13.8 billion light years, subtracting only how long it took stars and galaxies to form after the Big Bang.
What is the Big Bang and why does it matter?
One of them is the Big Bang, or the idea that the Universe began a certain time ago: 13.8 billion years ago to be precise. That’s the first moment we can describe the Universe as we know it to be today: full of matter and radiation, and the ingredients that would eventually grow into stars, galaxies, planets and human beings.
How big is the universe?
You might think, in a Universe limited by the speed of light, that would be 13.8 billion light years: the age of the Universe multiplied by the speed of light. But 13.8 billion light years is far too small to be the right answer. In actuality, we can see for 46 billion light years in all directions, for a total diameter of 92 billion light years.