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cosmology

Reaching for the Multiverse
Infinity and Beyond: The Ultimate Test

Multiverse Collisions May Dot the Sky

Early in cosmic history, our universe may have bumped into another — a primordial clash that could have left traces in the Big Bang’s afterglow.

Infinity and Beyond: The Ultimate Test

In a Multiverse, What Are the Odds?

Testing the multiverse hypothesis requires measuring whether our universe is statistically typical among the infinite variety of universes. But infinity does a number on statistics.

astrophysics

Dwarf Galaxies Dim Hopes of Dark Matter

For five years physicists have been tantalized by possible evidence of dark matter in the Milky Way’s center. But new results from small satellite galaxies have complicated the story.

BICEP2 graphic.
cosmology

‘Big Bang Signal’ Could All Be Dust

Cosmic dust in the high latitudes of the Milky Way could account for the entire swirl pattern that had been presented as proof of a leading Big Bang theory, according to a new data analysis from the Planck satellite.

Blanco telescope.
Q&A

Finding Dark Energy in the Details

The astrophysicist Joshua Frieman seeks to pinpoint the mysterious substance driving the accelerating expansion of the universe.

Katherine Freese
Q&A

In Search of Dark Stars

Katherine Freese, a physicist who will soon lead the Nordic Institute for Theoretical Physics, reflects on the hunt for dark matter and how dark matter heating may have produced the first stars.

David Spergel
Q&A

A Bold Critic of the Big Bang’s ‘Smoking Gun’

The cosmologist David Spergel explains why a widely publicized gravitational-wave discovery could be wrong, and how the “overreaching” study could affect the public’s perception of science.

Q&A

Early-Universe Explorer Looks for Answers

Chao-Lin Kuo, who helped design the experiment that claimed to have found evidence of gravitational waves from the Big Bang, isn’t bothered by criticism that cosmic dust may account for his results.

Bicep2 B-modes
cosmology

Possible Echo of Big Bang Detected

Scientists report the possible discovery of primordial gravitational waves, ripples in space-time that carry a record of how the universe began.