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Dark Energy
For every proton, there were over a billion others that annihilated away with an antimatter counterpart. So where did all that energy go?
A new measurement offers insights on the density of the mysterious force driving the Universe's expansion.
Today, the star-formation rate across the Universe is a mere trickle: just 3% of what it was at its peak. Here's what it was like back then.
From how life emerged on Earth to why we dream, these unanswered questions continue to perplex scientists.
Atomic nuclei form in minutes. Atoms form in hundreds of thousands of years. But the "dark ages" rule thereafter, until stars finally form.
Freethink's weekly countdown of the biggest space news, featuring Starship's second test flight, a new "dark mysteries" telescope, and more.
Cosmic inflation is the state that preceded and set up the hot Big Bang. Here's what the Universe was like during that time period.
Sometimes, going "deeper" doesn't reveal the answers you seek. By viewing more Universe with better precision, ESA's Euclid mission shines.
If the Universe is expanding, and the expansion is accelerating, what does that tell us about the cause of the expanding Universe?
From ancient Greek cosmology to today's mysteries of dark matter and dark energy, explore the relentless quest to understand the Universe's invisible forces.
Measurements of the acceleration of the universe don’t agree, stumping physicists working to understand the cosmic past and future. A new proposal seeks to better align these estimates — and is likely testable.
The hot Big Bang was an energetic, brilliantly luminous event. Today's Universe is alight with stars. But in between, the dark ages ruled.
Cosmology is unlike other sciences. When our view of the Universe changes, so does our understanding of philosophy and science itself.
When it comes to predicting the energy of empty space, the two leading theories disagree by a factor of 100 googol quintillion.
There are a few clues that the Universe isn't completely adding up. Even so, the standard model of cosmology holds up stronger than ever.
The Universe isn't just expanding, the expansion is also accelerating. If that's true, how will the Milky Way and Andromeda eventually merge?
Two fundamentally different ways of measuring the expanding Universe disagree. What's the root cause of this Hubble tension?
Today, our observable Universe extends for 46 billion light-years in all directions. But early on in our history, things were much smaller.
For many years, cosmologists have claimed the Universe is 13.8 billion years old. A new paper says no, it's 26.7 billion. How do we decide?
A cute mathematical trick can "rescale" the Universe so that it isn't actually expanding. But can that "trick" survive all our cosmic tests?
The farther away they get, the smaller distant galaxies look. But only up to a point, and beyond that, they appear larger again. Here’s how.
In many ways, we are still novices playing with toy models seeking to understand the stars.
In a far-reaching discovery with astrophysicist Karolina Garcia, we discuss what's in the Universe and how it grew up.
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.
When Einstein gave General Relativity to the world, he included an extraneous cosmological constant. How did his 'biggest blunder' occur?
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.
If our Universe were born a little differently, there wouldn't have been any planets, stars, galaxies, or chemically interesting reactions.
The conservation of energy is one of the most fundamental laws governing our reality. But in the expanding Universe, that's just not true.
All forms of energy affect the expanding Universe. But if matter and radiation slow the expansion down, how does dark energy speed it up?
From quarks and gluons to giant galaxy clusters, everything that exists in our Universe is determined by what is (and isn't) bound together.