Future of our Universe (Part I)

Hello everyone, today we’re gonna talk about the future of the universe. This is one of the reasons why we study cosmology. We want to know the future of the universe. The last time we learned 73 percent of the energy budget of the universe is dark energy. And then this dark energy is accelerating expansion of the universe. So what happens in the future of this accelerating expansion of the universe?

So what is the future of this accelerating universe? Is it going to go back to the, uh, big crunch, shrink down to the big crunch, or is it going to expand forever? It looks like it’s going to expand forever. Let’s look at it. In about five billion years from now, the sun is going to end up its life. The sun, as you know, is shining through the, this nuclear fusion. Hydrogen atoms confused into helium atom, and then that’s creating the energy.

However, in five billion years, sun is going to use up all the hydrogen in it, and then it starts burning helium, then temperature is going to heat up, and the sun’s gonna boon, boost its size and it becomes the so-called red giant star. And because the red giant star is much bigger, and it’s going to thr- throttle the earth and the Mars, so this is probably end of the earth’s life. This is going to be inside the sun. And then in six billion years from now, our neighbor, Andromeda galaxy and our Milky Way galaxy is going to merge.

Maybe you have heard the Andromeda galaxy is blue-shifting toward us and the meta-galaxy is moving towards us, because both of these galaxies are big galaxy, and they got huge gravity, so we, they’re pulling each other, we’re pulling each other. And then in six billion years from now, this is going to happen, so Andromeda galaxy it’s a tiny spot on the sky right now, but it comes closer, and then closer and then starts to merge, and when you start, when these two galaxies merge there’ll be uh um star formation is triggered when galaxies disturbed by each other’s gravity.

Those red points and new star formation happening, and then it changes the sha- shape, because of the gravity, and eventually it becomes one giant elliptical galaxy. If you live long enough to see this, the night sky will be spectacular with looking at stars, new stars from both of these galaxies. That happens in six billion years.

So, this is a simulation of, uh, Andromeda and the Milky Way merging. Let’s take a look at it.

So, Andromeda galaxy and Milky Way galaxy, they get closer and closer and closer,

start gravitational interaction, and then start marching.

And then the shape of both these galaxies are disturbed,

and eventually these galaxies merge into one giant electrical galaxy. That’s happened about six billion years from night, from now.

Okay, then next time we continue to look at the farther future of the universe.