This episode is brought to you by  the Music for Scientists album, now available on all streaming services. [♪ INTRO].

Over the years, humans have made plenty of time  capsules to preserve snapshots of the past. But incredibly enough, long before we were around, the universe was already creating  time capsules of its own.

Today, we know of a handful of cosmic objects  that preserve clues about the distant past, from little balls of carbon  to huge groups of stars. And by exploring them, we can uncover some  amazing details about the universe around us. First, oddly enough, cosmic time  capsules don’t have to be very big.

In fact, some of them are microscopic. Like buckminsterfullerene molecules,  better known as buckyballs. These molecules are just a  billionth of a meter wide, and they’re made of 60 carbon atoms  in the shape of a soccer ball.

But even though they’re made  purely of carbon, when they form, sometimes they trap smaller  particles and carry them along. And that’s one thing that makes  buckyballs so interesting, because those trapped particles can say something about the environment where the molecules formed. For example, in a 1996 study, researchers were looking at buckyballs  that they found on meteorites.

They wanted to figure out if the  buckyballs had come from space, or if they formed on impact. So they heated the molecules to crack them  open and release the gases trapped inside. And they found helium, but  not like the kind on Earth.

See, this gas comes in two forms: helium-3 and helium-4, which have  different numbers of neutrons. Helium-4 is much more common overall, but  on Earth, the ratio is especially high. That’s because radioactive elements in Earth’s  crust and mantle are pumping this stuff out.

Meanwhile, in space, the ratio is much smaller. So by analyzing the composition of  the gas inside these buckyballs, scientists could tell that these little  carbon cages were extraterrestrial. But also… the ratio didn’t quite match  the environment in our solar system.

It was a little too high. So researchers suspected that  these buckyballs were old, and that they might even have formed around  a different star billions of years ago. If they’re right, that means these  molecules potentially preserved a snapshot of an environment around another star  before the solar system even formed.

Not all cosmic time capsules  are so tiny and obscure, though. Like, some of the most common ones we rely on to learn about the early  solar system are asteroids. Because they’re so much smaller than planets, asteroids don’t evolve the way  that planets do as they form.

So they can tell us what the solar  system was like billions of years ago. The problem is, anything that  orbits in the inner solar system is still subject to the Sun’s heat and  radiation, so it’s not perfectly preserved. But there is one type of space debris  that’s almost pristine: rocky comets.

Generally, comets are icy, dusty  leftovers from the formation of planets that got kicked into the  outskirts of the solar system. Normally, when they swoop  close to the Sun, they heat up, and some of the ice vaporizes,  leaving behind a long, shining tail. But astronomers have also discovered a couple  of strange comets with barely any tail; ones that aren’t really vaporizing.

They call them Manx comets,  like the tailless Manx cat. And astronomers expect them to be especially  good time capsules of the early solar system. They’re likely made of the  same stuff that formed Earth.

But since they stayed so far from the Sun,  they haven’t gotten cooked like most asteroids. So, the amount of water and other  chemicals they release as they heat up could represent the composition of the  disk of material Earth formed from. Since this discovery is relatively new, no one has scheduled a mission  to one of these comets just yet.

But we are getting better at sampling  asteroids and comets all the time, so there’s no reason we couldn’t do  this in the future to learn more. Finally, looking at the early  solar system is one thing. But looking into the early  universe is a whole other story.

To do it, you often have to  look at objects really far away. That’s because light takes time to travel, so light from the most distant objects left  when those objects were still very young. Meanwhile, most closer objects formed  when the universe was much more evolved, so they can’t tell us much about the past.

Except, now and then, we can get  a glimpse of an ancient universe right in our own neighborhood,  thanks to globular clusters. These are groups of stars  that first started forming less than a billion years after the Big Bang  as gravity pulled the first stars together. As the universe changed, many of these  clusters got pulled into galaxies, but they themselves haven’t changed much, because they’re so dense that they stay  tightly bound together as one unit.

For example, the globular cluster NGC  1466 is basically right next door, in the galaxy known as the Large Magellanic Cloud. But scientists think it formed 13.1 billion  years ago, shortly after the Big Bang. These ancient clusters can tell us a lot, but one thing we can use them for  is estimating the universe’s age.

We do have other ways of measuring this,  but it’s important to check our work, especially when we’re throwing around  numbers like 13.8 billion years. The key to this technique is that,  since globular clusters formed so early, the oldest ones should be about  as old as the universe itself. So in a 2020 study, astronomers set out to  estimate the ages of different globular clusters, judging by the composition  of the stars inside of them.

And fortunately, the numbers check out. What’s incredible about all these time capsules is that they contain snapshots of the  universe at different points in time. And by cracking them open, we  can start to piece together how it went from a bunch of hot  gas swirling in total darkness to a universe full of light,  structure, and even living things.

If that kind of exploration and discovery  is making you feel all the things, you might enjoy an album  called Music for Scientists. It’s a tribute to those who’ve poured countless  hours and energy into science-driven work, and it was inspired by the incredible,  knowable wonders in the universe around us. It’s a project by Patrick Olsen that  celebrates scientific contributions to society through experimentation and a commitment to truth.

If that sounds like something you’d enjoy,  you can find a link to the music video “For Your Love” below or stream the  album on all major music services. [♪ OUTRO].