Cosmology

Cosmology

overview effect
There's an entire Universe out there. So, with all that space, all those planets, and all those chances at life, why do we all live here?
big bang mirage
A cute mathematical trick can "rescale" the Universe so that it isn't actually expanding. But can that "trick" survive all our cosmic tests?
blue marble not 24 hours apollo 17
As the Earth spins and wobbles on its axis and revolves elliptically around the Sun, each day changes from the last. "24 hours" isn't right.
a drawing of a spiral with a space in the background.
The multiverse pushes beyond the limits of the scientific method. From our vantage point in the Universe, we cannot know if it's real.
a close up of two stars in the sky.
In many ways, we are still novices playing with toy models seeking to understand the stars. 
cold fuzzy dark matter simulations
In a far-reaching discovery with astrophysicist Karolina Garcia, we discuss what's in the Universe and how it grew up.
proton internal structure
If we waited long enough, would even protons themselves decay? The far future stability of the Universe depends on it.
zelda depths reionization
What do the dark recesses of the early Universe and Zelda: Tears of the Kingdom have in common? More than you could have ever hoped for.
a computer generated image of a speaker and a box.
How are we to deal with the quantization of spacetime and gravity?
periodic table
Up until 2002, we thought that the heaviest stable element was bismuth: #83 on the periodic table. That's absolutely no longer the case.
globular cluster terzan 5
Sun-like stars live for around 10 billion years, but our Universe is only 13.8 billion years old. So what's the maximum lifetime for a star?
a blue circle surrounded by red lines on a white background.
Neuroscientist and author Bobby Azarian explores the idea that the Universe is a self-organizing system that evolves and learns.
NGC 1277 red and dead
With hundreds of billions of stars burning bright, some galaxies are already dead. Their inhabitants might not know it, but we're certain.
warm-hot intergalactic medium sculptor wall
Just by observing the tiny amount of deuterium left over from the Big Bang, we can determine that dark matter and dark energy must exist.
a computer generated image of a wave
There is no such thing as a void in the Universe.
hubble tension
When Einstein gave General Relativity to the world, he included an extraneous cosmological constant. How did his 'biggest blunder' occur?
Loneliest galaxy MCG+01–02–015
With no other galaxies in its vicinity for ~100 million light-years in all directions, it's as isolated and lonely as a galaxy can be.
a painting of a boat floating on a body of water.
Spiritual experiences can be explained in terms of a highly evolved brain. But they also can be extremely meaningful.
John Templeton Foundation
Two breathtaking pictures of a galaxy and a star taken by the Hubble telescope, highlighting the beauty and cosmic magnitude that fuels the Hubble tension.
There are two methods to measure the expansion rate of the Universe. The results do not agree with each other, and this is a big problem.
black hole emission radiation
In 1974, Hawking showed that black holes aren't stable, but emit radiation and decay. Nearly 50 years later, it isn't just for black holes.
warp field stars
The concept of ‘relativistic mass’ has been around almost as long as relativity has. But is it a reasonable way to make sense of things?
an image of a colorful object with a black background.
Particle physicists use gigantic accelerators to investigate the infinitesimal.
big bang expanding universe
It's been 100 years since we discovered that the Universe was expanding. But if it's expanding, then what is it expanding into?
multiverse
If our Universe were born a little differently, there wouldn't have been any planets, stars, galaxies, or chemically interesting reactions.
a black and white photo of stars in the sky.
Perhaps the whole Universe is the result of a vacuum fluctuation, originating from what we could call quantum nothingness. 
Fomalhaut debris system ALMA Keck JWST
A surprising JWST discovery around Fomalhaut has a different, superior explanation: not a great dust cloud, but a mere background object.
asteroid deliver organics to Earth
When the Universe was first born, the ingredients necessary for life were nowhere to be found. Only our "lucky stars" enabled our existence.
a painting of a blue and yellow ball on a black background.
We can reasonably say that we understand the history of the Universe within one-trillionth of a second after the Big Bang. That's not good enough.
a bright star surrounded by stars in the sky.
Archaeologists can learn how societies lived by studying what they left behind when they died. Astronomers are doing much the same thing.
A diagram showing the structure of an electroweak big bang.
The problem of the electroweak horizon haunts the standard model of cosmology and beckons us to ask how deep a rethink the model may need.