11 articles tagged with #dark-energy
Two carefully checked ways of measuring how fast the universe expands disagree by roughly 8 to 10 percent, a gap near 5 sigma. Either a hidden error remains, or standard cosmology is incomplete.
The observable universe is 93 billion light-years across, but the real universe is far bigger — possibly infinite. Here's how we know.
The Big Bang explained: evidence from Hubble's law, the CMB, and primordial element abundances, plus the timeline of cosmic history and the universe's fate.
What is dark matter and dark energy? Discover the invisible forces shaping 95% of the universe — from galaxy rotation curves to the accelerating cosmos.
Hubble launched with a flawed mirror and came back from the brink to become humanity's greatest eye on the cosmos.
Dark energy makes up 68% of the universe's energy content and drives cosmic acceleration. If it vanished, the universe would no longer expand at an accelerating rate. Instead, gravity would decelerate expansion, and the universe would either stabilize into a steady expansion, re-contract (Big Crunch), or remain nearly stable — depending on the matter density.
The universe has been expanding for 13.8 billion years, and dark energy is currently accelerating that expansion. If it suddenly reversed and the universe began contracting, we would be heading toward a 'Big Crunch' — but the change would be too slow for any individual to notice.
In 1998, two teams studying distant Type Ia supernovae found that cosmic expansion is speeding up. The cause, dark energy, makes up about 68% of the universe's energy budget, and nobody knows what it is.
Dark flow is the claimed observation that galaxy clusters across the observable universe are moving in the same direction, toward a region beyond what we can see. If real, it could indicate a gravitational pull from structures outside the observable universe. The claim is controversial and not accepted by most cosmologists.
The universe began 13.8 billion years ago and will end — eventually. But how? Heat death, the Big Rip, the Big Crunch, and vacuum decay are all on the table. Here's what physics actually predicts for the final fate of everything.
The observable universe is 93 billion light-years across. The full universe is bigger — possibly infinitely so. Here's what we can measure, what we can't, and why.