Universe Expansion

Universe Expansion

An artist's impression of an asteroid in space.
The detection of two celestial interlopers careening through our solar system has scientists eagerly anticipating more.
Illustration of the solar system's planets and their predicted fates, with some being swallowed by the sun as it dies and others stripped of their atmospheres or ejected.
For now, our Solar System's eight planets are all safe, and relatively stable. Billions of years from now, everything will be different.
An image of a fireball emerging from a dark background.
Until the Apollo missions, we had no idea how the moon got here, just a series of educated guesses. They rewrote the story of the moon’s origins.
Planets in varying sizes orbiting around a bright central star in a purple-hued cosmos, where life persists.
There are plenty of life-friendly stellar systems in the Universe today. But at some point in the far future, life's final extinction will occur.
A blue t-shirt with a yellow circle and arrow, representing the universe.
The second law of thermodynamics tells us that entropy always increases. But that doesn't mean it was zero at the start of the Big Bang.
nasa merge black hole
So far, gravitational waves have revealed stellar mass black holes and neutron stars, plus a cosmic background. So much more is coming.
An image of a spiral galaxy taken by the JWST in space.
Almost every large structure in the Universe displays a 5:1 dark matter-to-normal matter ratio. Here's how some galaxies defy that rule.
Einstein field equations
Although many of Einstein's papers revolutionized physics, there's one Einsteinian advance, generally, that towers over all the rest.
A cluster of galaxies with a star in the middle.
Beyond the planets, stars, and Milky Way lie ultra-distant objects: galaxies and quasars. Here's how far back we've seen throughout history.
A digitally enhanced view of a crescent planet Earth with a galaxy in the background.
The Earth that exists today wasn't formed simultaneously with the Sun and the other planets. In some ways, we're quite a latecomer.
An image of a spiral galaxy in space.
In 1924, Edwin Hubble found proof that the Milky Way isn't the only galaxy in the Universe.
A diagram showing the structure of a galaxy.
The Universe didn't begin with a bang, but with an inflationary "whoosh" that came before. Here are the biggest questions that still remain.
A bright light in the sky.
As planets with too many volatiles and too little mass orbit their parent stars, their atmospheres photoevaporate, spelling doom for some.
A tunnel is being constructed in a tunnel.
The DUNE project will beam tiny neutrinos across vast distances. But the first step involved moving a heavier material: 1 million tons of rock.
wormhole nasa illustration
Without wormholes, warp drive, or some type of new matter, energy, or physics, everyone is limited by the speed of light. Or are they?
A computer-generated image of a bright celestial object with an accretion disk, possibly representing what the sun looked like when it was born.
It took 9.2 billion years of cosmic evolution before our Sun and Solar System even began to form. Such a small event has led to so much.
Composition of the dark energy prominence universe showing percentages of dark energy, dark matter, and visible matter.
Early on, only matter and radiation were important for the expanding Universe. After a few billion years, dark energy changed everything.
Nasa's JWST captures spiral galaxies in a series of photos.
Stars are born, live, and die within the spiral arms of galaxies like the Milky Way. These 19 JWST spirals deliver unprecedented riches.
An image of a galaxy cluster.
If our Milky Way were located in the Virgo cluster instead of the Local Group, chances are we'd already be a "red and dead" galaxy.
The Milky Way, a galaxy in space filled with stars, grew up.
Our own galaxy, the Milky Way, is both completely normal and absolutely remarkable in a number of ways. Here's the story of our cosmic home.
An image of a red light shining on a dark background.
Millennia ago, philosophers like Anaximander grasped that nature is the ultimate recycler.
A digitally generated image of a glowing, elongated object framed by a translucent rectangle against a dark background with cosmic web-like structures.
On the largest cosmic scales, galaxies line up along filaments, with great clusters forming at their intersection. Here's how it took shape.
An image of a man standing in a black hole.
Want to avoid getting "spaghettified" by a black hole? Steer clear of the smaller ones.
A giant, colorful ring of glowing lines suspended in space
Astronomers claim to have found structures so large, they shouldn't exist. With such biased, incomplete observations, perhaps they don't.
A map of a cluster of stars illustrating star birth.
Here in our Solar System, we only have one star: a singlet. For many systems, including the highest-mass ones, that's anything but the norm.
A black background with the earth in the foreground.
Two scientists recently wagered a bottle of whiskey. The bet? Whether we'll find evidence of advanced extraterrestrial life in the next 15 years.
primordial black holes
Today, supermassive black holes and their host galaxies tell a specific story in terms of mass. But JWST reveals a different story early on.
An image of a purple galaxy in space.
Observations of an enormous cosmic structure, dubbed the "Big Ring," seem to violate the Copernican principle.
An image of a sphere with stars in it.
For every proton, there were over a billion others that annihilated away with an antimatter counterpart. So where did all that energy go?
supernova remnant star formation spitzer
One newly discovered, ancient star has a composition unlike any other. Explaining its existence is already blowing astronomers' minds.