238: When will the universe stop expanding?
Sep 1, 2026 · 16 min · 8 segments
A question from Jacob, age 7. Dr. Andrés Plazas Malagón answers. For more on Dr. Malagón's work, see episode…
Sep 1, 2026 · 16 min · 8 segments
A question from Jacob, age 7. Dr. Andrés Plazas Malagón answers. For more on Dr. Malagón's work, see episode…
Andrés Plazas MalagónGuest
Carrie NugentHost
I think a lot of times when you're a kid, you think that adults know everything, right? And even as adults, maybe we feel like we're in a time on this planet when we know so much, right? We have got libraries, we've got the internet, we've got all types of ways to like learn things.
But what you're saying is that most of the stuff in the universe is this dark energy, which is something we don't know what it is.
And it's totally different than the things we're familiar with, like planets and cats and stars.
And we just don't know what it is, but it's most of the stuff in the universe and it's a giant mystery.
And actually, most of the universe is made up of this dark energy I mentioned earlier.
70%, which is more than half of what the contents of the universe is.
I haven't mentioned the other unknown component, which is called dark matter, because we're talking about the expansion of the universe.
But there's another type of component of the universe in which we don't know exactly what it is.
It doesn't accelerate, it doesn't drive the expansion of the universe like dark energy, but dark matter is something else.
And dark matter is actually responsible for providing the gravity that holds galaxies together.
And if you put these two together, sometimes people call it the dark sector.
So that means that the other 5% is everything that you just mentioned.
Planets, the stars, the table you're sitting on right now, the chair you're sitting on right now.
everything you're learning in chemistry and everything that we thought that we knew in the world.
And it's fascinating, it's humbling, it's exciting because we haven't figured it out.
I think a lot of times when you're a kid, you think that adults know everything, right? And even as adults, maybe we feel like we're in a time on this planet when we know so much, right? We have got libraries, we've got the internet, we've got all types of ways to like learn things.
But what you're saying is that most of the stuff in the universe is this dark energy, which is something we don't know what it is.
And it's totally different than the things we're familiar with, like planets and cats and stars.
And we just don't know what it is, but it's most of the stuff in the universe and it's a giant mystery.
And actually, most of the universe is made up of this dark energy I mentioned earlier.
70%, which is more than half of what the contents of the universe is.
I haven't mentioned the other unknown component, which is called dark matter, because we're talking about the expansion of the universe.
But there's another type of component of the universe in which we don't know exactly what it is.
It doesn't accelerate, it doesn't drive the expansion of the universe like dark energy, but dark matter is something else.
And dark matter is actually responsible for providing the gravity that holds galaxies together.
And if you put these two together, sometimes people call it the dark sector.
So that means that the other 5% is everything that you just mentioned.
Planets, the stars, the table you're sitting on right now, the chair you're sitting on right now.
everything you're learning in chemistry and everything that we thought that we knew in the world.
And it's fascinating, it's humbling, it's exciting because we haven't figured it out.
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