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Scientists might be about to uncover one of the universe's biggest mysteries.
A new experiment looks to use gravitational waves – tiny ripples in the fabric of spacetime – to unlock the truth of why the universe is expanding so quickly and so unexpectedly.
Astronomers discovered in the 90s that galaxies like our own Milky Way were flying apart super quickly. And they were even more shocked to find that they appeared to be accelerating, picking up speed as they were flung through the cosmos.
Nasa's most stunning pictures of spaceShow all 30 1 /30Nasa's most stunning pictures of space Nasa's most stunning pictures of space Solar Flare An image from Nasa's Solar Dynamics Observatory (SDO) shows a 200,000 mile long solar filament ripping through the Sun's corona in September 2013
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Nasa's most stunning pictures of space Nasa Celebrates 50 Years of Spacewalking For 50 years, NASA has been "suiting up" for spacewalking. In this 1984 photograph of the first untethered spacewalk, NASA astronaut Bruce McCandless is in the midst of the first "field" tryout of a nitrogen-propelled backpack device called the Manned Maneuvering Unit (MMU)
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Nasa's most stunning pictures of space A Hubble Cosmic Couple The spectacular cosmic pairing of the star Hen 2-427 — more commonly known as WR 124 — and the nebula M1-67 which surrounds it
ESA/Hubble & NASA
Nasa's most stunning pictures of space Veil Nebula Supernova Remnant Nasa's Hubble Space Telescope has unveiled in stunning detail a small section of the Veil Nebula - expanding remains of a massive star that exploded about 8,000 years ago
Nasa's most stunning pictures of space The Soyuz TMA-15M rocket launch The Soyuz TMA-15M rocket launches from the Baikonur Cosmodrome in Kazakhstan on Monday, Nov. 24, 2014, carrying three new astronauts to the International Space Station. It also took caviar, ready for the satellite's inhabitants to celebrate the holidays
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Nasa's most stunning pictures of space Earth from the ISS From the International Space Station, Expedition 42 Flight Engineer Terry W. Virts took this photograph of the Gulf of Mexico and U.S. Gulf Coast at sunset
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Nasa's most stunning pictures of space Black Hole Friday Nasa celebrated Black Friday by looking into space instead — sharing pictures of black holes
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Nasa's most stunning pictures of space NuSTAR X-rays stream off the sun in this image showing observations from by NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, overlaid on a picture taken by NASA's Solar Dynamics Observatory (SDO)
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Nasa's most stunning pictures of space Cassiopeia A c A false colour image of Cassiopeia A comprised with data from the Spitzer and Hubble Space Telescopes and the Chandra X-Ray observatory
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Nasa's most stunning pictures of space Orion Capsule splashes down The Orion capsule jetted off into space before heading back a few hours later — having proved that it can be used, one day, to carry humans to Mars
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Nasa's most stunning pictures of space Earth Observations From Gemini IV in 1965 This photograph of the Florida Straits and Grand Bahama Bank was taken during the Gemini IV mission during orbit no. 19 in 1965. The Gemini IV crew conducted scientific experiments, including photography of Earth's weather and terrain, for the remainder of their four-day mission following Ed White's historic spacewalk on June 3
Nasa's most stunning pictures of space Frosty slopes of Mars This image of an area on the surface of Mars, approximately 1.5 by 3 kilometers in size, shows frosted gullies on a south-facing slope within a crater. The image was taken by Nasa's HiRISE camera, which is mounted on its Mars Reconaissance Orbiter
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Nasa's most stunning pictures of space Yellowstone from space NASA astronaut Reid Wiseman shared this image of Yellowstone via his twitter account
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Nasa's most stunning pictures of space Saturn This near-infrared color image shows a specular reflection, or sunglint, off of a hydrocarbon lake named Kivu Lacus on Saturn's moon Titan
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Nasa's most stunning pictures of space Worlds Apart Although Mimas and Pandora, shown here, both orbit Saturn, they are very different moons. Pandora, "small" by moon standards (50 miles or 81 kilometers across) is elongated and irregular in shape. Mimas (246 miles or 396 kilometers across), a "medium-sized" moon, formed into a sphere due to self-gravity imposed by its higher mass
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Nasa's most stunning pictures of space Solar Flare An X1.6 class solar flare flashes in the middle of the sun in this image taken 10 September, captured by NASA's Solar Dynamics Observatory
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Nasa's most stunning pictures of space Large Magellanic Cloud galaxy An image of the Large Magellanic Cloud galaxy seen in infrared light by the Herschel Space Observatory. Regions of space such as this are where new stars are born from a mixture of elements and cosmic dust
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Nasa's most stunning pictures of space Mars Rover Spirit Nasa's Mars Rover Spirit took the first picture from Spirit since problems with communications began a week earlier. The image shows the robotic arm extended to the rock called Adirondack
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Nasa's most stunning pictures of space Morning Aurora From the Space Station Nasa astronaut Scott Kelly captured this photograph of the green lights of the aurora from the International Space Station
Nasa/Scott Kelly
Nasa's most stunning pictures of space Launch of History - Making STS-41G Mission in 1984 The Space Shuttle Challenger launches from Florida at dawn. On this mission, Kathryn Sullivan became the first U.S. woman to perform a spacewalk and Marc Garneau became the first Canadian in space. The crew of seven was the largest to fly on a spacecraft at that time, and STS-41G was the first flight to include two female astronauts
Nasa's most stunning pictures of space A Fresh Perspective on an Extraordinary Cluster of Galaxies Galaxy clusters are often described by superlatives. After all, they are huge conglomerations of galaxies, hot gas, and dark matter and represent the largest structures in the Universe held together by gravity
Nasa's most stunning pictures of space Hubble Sees a Galactic Sunflower The arrangement of the spiral arms in the galaxy Messier 63, seen here in an image from the Nasa Hubble Space Telescope, recall the pattern at the center of a sunflower
ESA/Hubble & NASA
Nasa's most stunning pictures of space Pluto image Four images from New Horizons’ Long Range Reconnaissance Imager (LORRI) were combined with colour data from the Ralph instrument to create this enhanced colour global view of Pluto
Nasa's most stunning pictures of space Fresh Crater Near Sirenum Fossae Region of Mars The HiRISE camera aboard Nasa's Mars Reconnaissance Orbiter acquired this closeup image of a "fresh" (on a geological scale, though quite old on a human scale) impact crater in the Sirenum Fossae region of Mars. This impact crater appears relatively recent as it has a sharp rim and well-preserved ejecta
Nasa's most stunning pictures of space Hubble Peers into the Most Crowded Place in the Milky Way This Nasa Hubble Space Telescope image presents the Arches Cluster, the densest known star cluster in the Milky Way
NASA & ESA
Nasa's most stunning pictures of space An Astronaut's View from Space Nasa astronaut Reid Wiseman tweeted this photo from the International Space Station on 2 September 2014
Nasa's most stunning pictures of space Giant Landform on Mars On Mars, we can observe four classes of sandy landforms formed by the wind, or aeolian bedforms: ripples, transverse aeolian ridges, dunes, and what are called “draa”
Nasa's most stunning pictures of space Expedition 39 Landing A sokol suit helmet can be seen against the window of the Soyuz TMA-11M capsule shortly after the spacecraft landed with Expedition 39 Commander Koichi Wakata of the Japan Aerospace Exploration Agency (JAXA), Soyuz Commander Mikhail Tyurin of Roscosmos, and Flight Engineer Rick Mastracchio of NASA near the town of Zhezkazgan, Kazakhstan
(NASA/Bill Ingalls)
Nasa's most stunning pictures of space Jupiter's Great Red Spot Viewed by Voyager I Jupiter is the largest planet in the solar system and perhaps the most majestic. Vibrant bands of clouds carried by winds that can exceed 400 mph continuously circle the planet's atmosphere
Nasa's most stunning pictures of space Chandra Observatory Sees a Heart in the Darkness This Chandra X-Ray Observatory image of the young star cluster NGC 346 highlights a heart-shaped cloud of 8 million-degree Celsius gas in the central region
They theorised that an unknown and mysterious force, known as Dark Energy, was the cause of the strange behaviour.
Almost a century ago Albert Einstein conjured up a similar concept in his calculations - the Cosmological Constant - but then discarded it, believing he had made a mistake.
But there is another possibility - across intergalactic distances, gravity may not work the way it is supposed to.
Now scientists at the University of Edinburgh believe they have found how to resolve the puzzle by measuring the speed at which gravitational waves cross the universe.
If the space-time ripples are shown shown to propagate at the speed of light, it would rule out alternative gravity theories that exclude Dark Energy.
On the other hand, if their speed ever differs from that of light, the Dark Energy theory would have to be revised.
Such an experiment could be conducted at the Laser Interferometer Gravitational Wave Observatory (Ligo) in the US, whose twin detectors 2,000 miles apart confirmed the existence of gravitational waves for the first time two years ago.
Dr Lucas Lombriser, from the University of Edinburgh's School of Physics and Astronomy, said: "Recent direct gravitational wave detection has opened up a new observational window to our universe.
"Our results give an impression of how this will guide us in solving one of the most fundamental problems in physics."
The new research is published in the journal Physics Letters B.
Gravitational waves are generated by some of the most powerful events in the universe, such as colliding black holes or super-massive neutron stars.
Additional reporting by Press Association
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