Prøve GULL - Gratis

Does the Universe expand faster than light?

BBC Sky at Night Magazine

|

February 2023

Govert Schilling continues to explain cosmology's confusing concepts In part 2 of our series

Does the Universe expand faster than light?

Our Universe is huge. In each and every direction on the sky, powerful telescopes observe galaxies whose light took more than 10 billion years to arrive at Earth. But wait - if we receive such ancient light from two opposite directions, and if the Big Bang happened just' 13.8 billion years ago, does that mean that the Universe is expanding faster than light? And wouldn't that violate Albert Einstein's theory of relativity, which says that the speed of light is an absolute limit? The answer may surprise you. But first, we need to take a closer look at the expansion of the Universe.

As described in the previous instalment of this series, we know that the Universe is expanding because galaxies appear to speed away from each other - their mutual distances are continuously increasing. But we also saw that cosmic expansion shouldn't be pictured as galaxies racing through empty space at incredibly high velocities. Instead, it is empty space itself that expands, pushing the galaxies ever further away from each other.

FLERE HISTORIER FRA BBC Sky at Night Magazine

BBC Sky at Night Magazine

BBC Sky at Night Magazine

How to find a speck in space

New Horizons proves stellar parallax can locate a probe in the vastness, using the light of just two stars

time to read

4 mins

October 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

FIRST CONTACT

Seven missions that gave us our first real look at alien worlds

time to read

6 mins

October 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

Possible planet found at Alpha Centauri A

If true, it would be the closest exoplanet ever found in a habitable zone

time to read

2 mins

October 2025

BBC Sky at Night Magazine

Get to know lunar rays

A full Moon might bleach the sky and thwart your stargazing, but it's the best time to catch the magnificent lunar rays

time to read

3 mins

October 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

JWST decodes the chaos behind paint-splash nebula

A companion star may be sculpting tangled NGC 6072, a rare multipolar planetary nebula

time to read

1 min

October 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

INSIDE THE SKY AT NIGHT

September's Sky at Night episode tackled the Hubble constant. George Dransfield considers how some of the cornerstones of science aren't as rock-solid as we thought

time to read

3 mins

October 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

Bridge of stray stars revealed

Dark Energy Camera image of galaxy cluster Abell 3667 brings cosmic history into focus

time to read

1 min

October 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

Stargazing in the Atacama Desert

Becca Marsh tours Chile's high Atacama Desert - home to some of the darkest skies and most advanced astronomical observatories on the planet - and discovers a stargazing destination like no other

time to read

7 mins

October 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

Titan's lakes could form protocells

Study shows conditions are right to create vesicles, key structures in the origin of life

time to read

1 min

October 2025

BBC Sky at Night Magazine

BBC Sky at Night Magazine

Earliest black hole discovered

The supermassive black hole dates from just 500 million years after the Big Bang

time to read

2 mins

October 2025

Translate

Share

-
+

Change font size