How fast is the universe expanding? It’s one of the greatest puzzles of modern physics. But now a team of researchers claims to have cracked it, and their answer could hold the clue to the fate of our galaxy – and every other.
Cosmologists working as part of the H0LiCOW collaboration (yes, really) have been observing how light from distant quasars – super bright galaxy cores – is bent around the many galaxies in the middle-distance.
Using the Hubble telescope, the scientists were able to measure over time how long it took for different bursts of the quasars’ light to reach Earth, or at least the low-orbit in which Hubble sits.
The longer the delays between each burst, which are just a flicker when they reach Hubble, the longer the path. This measurement is directly related to the speed of the universe’s expansion, the Hubble Constant.
With some pretty complicated maths, the scientists came to the conclusion that the universe was expanding at 72 kilometres a second per megaparsec.
That’s really, really fast.
Each megaparsec is equivalent to about 3 million light years, so every 3 million light years out, the universe is expanding 72 kilometres/s faster, which converts to around 161,000 mph.
It’s also faster than an established estimate based on cosmic microwave background radiation from the start of history, which, critically, fits our current understanding of the universe.
But the H0LiCOW team claims their lensing technique is a more accurate representation of the speed of expansion now.
“Our method is the most simple and direct way to measure the Hubble constant as it only uses geometry and General Relativity, no other assumptions,” said co-lead Frédéric Courbin from EPFL, Switzerland.
Significantly, the figure also chimes with other recent estimates of the rate of expansion drawn from observations of the local universe.
Sherry Suyu, leader of the research team, said this could have a profound impact on our understanding of cosmology.
“The expansion rate of the Universe is now starting to be measured in different ways with such high precision that actual discrepancies may possibly point towards new physics beyond our current knowledge of the universe,” Suyu added.
Speaking on Radio 4’s PM show, Karen Masters, an astronomer at Portsmouth University, said the measurements could have major implications for our understanding of how dark energy works together with dark matter to force the universe apart at an accelerating rate.
At the moment, both those forces are hypothetical, but Masters said they could have a very real impacts on the future of the universe: “The expansion will get strong enough to rip apart galaxies and even solar systems, but we’re talking trillions of years in the future.”
NASA’s Best Photos Of 2016
Edward H. White II, pilot of the Gemini 4 spacecraft, floats in the zero gravity of space with an earth limb backdrop circa November 1965.
Kinescope images of astronaut Commander Neil Armstrong in the Apollo 11 space shuttle during the space mission to land on the moon for the first time in history on July 20, 1969
The ascent stage of Orion, the Apollo 16 Lunar Module, lifts of from its descent stage to rendezvous with the Apollo 16 Command and Service Module, Casper, with astronaut Thomas Mattingly aboard in lunar orbit on 23rd April 1972.
Five NASA astronauts aboard the Space Shuttle Atlantis look out overhead windows on the aft flight deck toward their counterparts aboard the Mir Space Station in March of 1996.
Photograph of the Milky Way Galaxy captured by NASA's Spitzer Space Telescope. Dated 2007.
The exhaust plume from space shuttle Atlantis is seen through the window of a Shuttle Training Aircraft (STA) as it launches from launch pad 39A at the Kennedy Space Center July 8, 2011 in Cape Canaveral, Florida.
A United Launch Alliance Delta 4 rocket carrying NASA's first Orion deep space exploration craft sits on its launch pad as it is prepared for a 7:05 AM launch on December 4, 2014 in Cape Canaveral, Florida.
A military pilot sits in the cockpit of an X-15 experimental rocket aircraft, wearing an astronaut's spacesuit circa 1959.
Echo 1, a spherical balloon with a metalized skin, was launched by NASA on 12th August 1960. Once in orbit the balloon was inflated until it reached its intended diameter of 30 metres and it was then used as a reflector to bounce radio signals across the oceans.
Four views of Earth rising above the lunar horizon, photographed by the crew of the Apollo 10 Lunar Module, while in lunar orbit, May 1969.
American geologist and Apollo 17 astronaut Harrison Hagan Schmitt stands next to the US flag on the surface of the moon, during a period of EVA (Extra-Vehicular Activity) at the Taurus-Littrow landing site, December 1972.
The space shuttle 'Enterprise' (NASA Orbiter Vehicle 101) makes its way along Rideout Road (Alabama State Route 255) to the Marshall Space Flight Center near Huntsville, Alabama, 15th March 1978.
A crowd of people, viewed from behind, watch the launch of the first NASA Space Shuttle mission (STS-1), with Columbia (OV-102) soaring up into the sky, leaving a trail of exhaust smoke, in the distance from the launchpad at the Kennedy Space Center, Florida, USA, 12 April 1981.
Astronaut Bruce McCandless II photographed at his maximum distance (320 ft) from the Space Shuttle Challenger during the first untethered EVA, made possible by his nitrogen jet propelled backpack (Manned Manuevering Unit or MMU) in 1984.
Aerial shot of the launch of Space Shuttle Discovery (STS-41-D) as it takes off, leaving a trail of exhaust smoke, from Kennedy Space Center, Florida, USA, 30 August 1984.
Two technicians inside a Space Shuttle external tank, circa 1985.
An astronaut's bootprint leaves a mark on the lunar surface July 20, 1969 on the moon. The 30th anniversary of the Apollo 11 Moon mission is celebrated July 20, 1999.
Astronaut Charles Moss Duke, Jr. leaves a photograph of his family on the surface of the moon during the Apollo 16 lunar landing mission, 23rd April 1972.