The auroral view while driving up Atigun Pass, North Slope Borough County, Alaska, US on November 1, 2013. Credit and copyright: Jason Ahrns.
Over the past several days the Sun has unleashed more than half a dozen major flares including four X-class events. The resulting aurora in some parts of the world have been beautiful. Here’s a collection of recent images taken by Jason Arhns in Alaska and one by Frank Olsen in Norway. In the image above, it seems the aurora is blanketing not only the sky, but the landscape as well!
See more below, as well as a video showing 23 of the 26 M- and X-class flares on the Sun between Oct. 23 and Oct. 28, 2013, as captured by NASA’s Solar Dynamics Observatory. It also shows the coronal mass ejections — great clouds of solar material bursting off the Sun into space — during that time as captured by the ESA/NASA Solar and Heliospheric Observatory.
Aurora seen over northern Norway on October 22, 2013. Credit and copyright: Frank Olsen.
Aurora over Sukakpak, Yukon-Koyukuk Census Area County, Alaska, US, November 1, 2013. Credit and copyright: Jason Ahrns.A stunning green aurora almost covers the sky, but peeking through are the Pleiades and the Andromeda Galaxy. Credit and copyright: Jason Ahrns.
Canadian Nathan Gray (right) is likely the youngest person to discover a supernova. The supernova candidate (left) is probably located some 600 million light-years away (image from the ARO--Dave Lane). Follow-up observations will soon be acquired to confirm the supernova's class and nature.
Young Canadian Nathan Gray, age 10, has discovered a supernova candidate in the field of the galaxy designated PGC 61330, which lies in the constellation of Draco (the dragon).
Nathan made the discovery while scanning astronomical images taken by Dave Lane, who runs the Abbey Ridge Observatory (ARO) which is stationed in Nova Scotia. Incidentally, Nathan may unseat his older sister, Kathryn Aurora Gray, as the youngest supernova discoverer by a mere 33 days.
Nothing is visible at the location of the supernova candidate in prior images of the field taken over the past two years, or Digitized Palomar Sky Survey images.
Kathryn Aurora Gray garnered worldwide fame when she discovered a supernova in the galaxy designated UGC 3378 (see the Universe Today article by Nancy Atkinson). The discovery eventually earned her an audience with astronauts such as Neil Armstrong (shown below).
Kathryn Aurora Gray’s discovery of a supernova earned her the chance to meet Neil Armstrong, Bill Anders (Apollo 8), Victor Gorbakto, and Jim Lovell (Apollo 8 & 13) (image credit: P. Gray/RASC).
Caroline Moore held the record prior to Kathryn as the youngest person to discover a supernova (Caroline was 14 at the time). Caroline subsequently had the honor of meeting President Obama at the White House (see the video below).
Supernova are immense explosions linked to the evolutionary end-state of certain stars. The explosions are so energetic that they can be observed in distant galaxies. Indeed, Nathan’s supernova could be some 600 million light years distant. Gazing into space affords humanity the opportunity to peer back in time. Despite the (finite) speed of light being a remarkable 300000 km/s, the light-rays must travel over “astronomical” distances.
Nathan’s discovery has been posted on the International Astronomical Union’s site, and its presence confirmed by US and Italian-based observers. Its provisional name is: PSN J18032459+7013306, and to get an official supernova designation a large telescope needs to confirm the unique supernova light signature (via a spectrum). Is the target a bona fide supernova?
“Given no motion, large distance from the galactic plane (ie. not likely a nova), and several optical confirmations, as well as its very close angular proximity to a faint galaxy, it is a supernova at any reasonable certainty,” said Lane, an astronomer in the Dept. of Astronomy & Physics at Saint Mary’s University, as well as the director of the Burke-Gaffney and Abbey Ridge astronomical observatories. “A significant fraction of
the supernova discoveries these days are not observed spectrographically due to the sheer number of them vs. telescope time.”
Nathan Gray is the son of Paul and Susan Gray.
*2013 10 31.9053 – update from the IAU: SN to be confirmed in PGC 61330 detected with 3 x 3 min images (exp 9 min). Astrometry: RA 18 03 24.12 Dec +70 13 26.4 (ref stars UCAC2) Photometry: 17.00CR +/-0.02 (USNO A2R Ref stars 163R, 170R, 172R, 173R). Measure on unfiltered image. Observer and measurer: Xavier Bros, ANYSLLUM OBSERVATORY, Ager, Spain. T-350mm f4.6. Link to image and further information: http://www.anysllum.com/PSN_PGC61330.jpg
Totality! As seen during the November 13th, 2012 total solar eclipse. (Image credit: Narayan Mukkavilli, used with permission).
The chase is on. On Sunday, November 3rd, the shadow of the Moon will cross the Earth for one last time in 2013. We recently wrote about the prospects for viewing this “hybrid” annular-total solar eclipse as it crosses the Atlantic and central Africa. Viewers from northern South America across the U.S. Eastern Seaboard up into the Canadian Maritimes will also be treated to a brilliant rising partial eclipse over the Atlantic at sunrise. Tickets are already in hand for many, as umbraphiles wing their way (cue Indiana Jones music) to dusty and exotic far off locales to stand briefly in the shadow of our Moon…
But what if it’s cloudy?
Once the bane of eclipse-chasers, you can now thwart our sometimes murky atmosphere by catching the solar eclipse online.
I remember our first experience with eclipse-chasing on the internet, trying to catch an eclipse broadcast on ye ole dial up modem from an internet café (remember internet cafes?) way back in the late 90s. This was pre-You Tube, pre-UStream. Needless to say, the tenuous connection afforded nary a frozen glimpse of the partially eclipsed Sun, and crashed all together at the onset of totality.
Fast forward to 2013, when ginormous data packets routinely fly around the globe.
True, this eclipse presents a challenge, as it crosses some pretty wild and unconnected terrain. But one standby that we can expect is the good people at Slooh, who have dispatched a broadcast team to the African nations of Gabon and Kenya:
As of this writing, Slooh looks to be going live at around 11:45 UT on Sunday November 3rd. This is 6:45 AM EST, which takes into account our “falling back” one hour to UT -5 hours on Sunday morning. Astronomer Brian Cox will be broadcasting live from Kenya, and the broadcast starts just over two hours prior to the first landfall of totality at just before 14:00 UT. From Gabon, Maximum totality will be a brief 1 minute and 5 seconds, and will dwindle to an even briefer 14 seconds over Lake Turkana in Kenya before ending as a brilliant sunset eclipse over Somalia and Ethiopia. A backup broadcast of the partial phases of the eclipse is also planned from Slooh’s home base site in the Canary Islands.
Another fascinating potential broadcast may come our way from the BRCK organization basing their observations of the eclipse from the shores of Lake Turkana in Kenya. Billed as “Your Backup Generator for the Internet,” BRCK’s mission is to bring broadband access internet to people in remote regions of the world. This weekend’s eclipse certainly qualifies. As of writing this on Halloween, October 31st, the BRCK team had gone into the field to “stress test” their webcasting capability onsite; follow them on Twitter as @brcknet for the latest updates. As of yet, there’s no embed for the broadcast, though we’ll be sure to drop it in if it surfaces!
There’s also some interesting science afoot during this eclipse as well. A recent press release out from Williams College notes that Field Memorial Professor of Astronomy and chair of the International Astronomical Union’s Working Group on Eclipses Jay Pasachoff will observe the eclipse, along with a student and tourist expedition from Gabon. A veteran eclipse chaser, Pasachoff will be working in concert with Dr. Vojtech Rusin of the Astronomical Institute of Slovakia, solar researchers Aris Voulgaris and Robert Lucas and William College students to study the ethereal solar corona. Satellite-based coronagraphs, such as the one employed by SOHO, can create an “artificial eclipse” of the Sun to study the corona, but also face the challenge of scattered light via a phenomenon known as Fresnel-diffraction. Pasachoff and team hope to combine their observations with those being routinely carried out by NASA, the European Space Agency and the Royal Observatory in Belgium to characterize the solar corona and improve our understanding of the space weather environment. Pasachoff’s expedition is being assisted via support from the South African Astronomical Observatory, Nommo Astronomia, the Gabon Astronomy Society and the Gabon Space Agency. Veteran eclipse chaser and historian Michael Zeiler (@EclipseMaps) has also joined up with Pasachoff’s group in Gabon.
In space, the NASA/JAXA joint solar observing Hinode spacecraft and ESA’s Sun watching Proba-2 will also catch several partial eclipses from their respective perches in low Earth orbit. Expect to see these pics in the days following Sunday’s eclipse.
We’ll be dropping in more broadcasts as they come to our attention this weekend here at Universe Today. Planning an ad-hoc webcast of the eclipse? Let us know in the comments below! Even if it’s just a brief view of the rising partially eclipsed Sun from the beach, its worth the effort. Just remember that you’ll need a fairly long focal length (in the range of 200mm or longer) and a proper solar filter for the Sun to appear like anything more than a washed out dot in the broadcast. And always run a test of your rig beforehand!
Good luck, happy eclipse chasing, and don’t forget to send those eclipse pics to Universe Today!
An exploding star in our home galaxy might be visible to Earth in the next 50 years, astronomers say in a new calculation of the odds of a nearby supernova.
This explosion would be too faint to prove a hazard to Earthlings, and in fact it may not even be visible with the naked eye in the starry sky. Its heat signature, however, would be seen in the right kind of camera as long as we could swing a telescope there fast enough.
“For [researchers], this study suggests that they have a solid chance of doing something that’s never been done before: detect a supernova fast enough to witness what happens at the very beginning of a star’s demise,” wrote Ohio State University in a press release about the research, which was led by university astronomer researcher Scott Adams.
Fishing Boats Meet the Milky Way on the Isle of Wight (south of England) on May 16, 2013. Credit and copyright: Chad Powell.
The challenge with observing a supernova in our own galaxy is the presence of cosmic dust that can sometimes obscure supernovae and other phenomena from our view. However, infrared light is not as badly affected by this and may be able to see something through the obscurity.
To jump on the supernova as it is happening, the scientists propose having a network in place to send out neutrino alerts when these particles, which would arrive at Earth first after an explosion, are detected on Earth. The key is to figure out the difference between neutrinos from space and neutrinos from other sources, such as nuclear reactors, the sun or even spurious glitches.
A University of Tokyo group led the building of a model of a new kind of neutrino detector, a model that is now operating underground in Japan. Called EGADS (Evaluating Gadolinium’s Action on Detector Systems), the water in the system would be “spiked” with a bit of gadolinium, which would reportedly assist with neutrino detections from outside of Earth.
The supernova that produced the Crab Nebula was detected by naked-eye observers around the world in 1054 A.D. This composite image uses data from NASA’s Great Observatories, Chandra, Hubble, and Spitzer, to show that a superdense neutron star is energizing the expanding Nebula by spewing out magnetic fields and a blizzard of extremely high-energy particles.
“When a neutrino from a Milky Way supernova enters the tank, it can collide with the water molecules and release energy, along with some neutrons,” Ohio State added. “Gadolinium has a great affinity for neutrons, and will absorb them and then re-emit energy of its own. The result would be one detection signal followed by another a tiny fraction of a second later—a “heartbeat” signal inside the tank for each detected neutrino.”
But what about a naked-eye supernova? The researchers say the probability of that is just 20% to 50% in the next century, with southern hemisphere residents having a better chance since more of the galaxy is visible there. The last instance of this happening, by the way, was in 1604.
The Witch Head Nebula, taken on October 24, 2013. Credit and copyright: ftherrmann on Flickr.
Boo! Here’s a great shot of the Witch Head nebula, so named because it resembles the profile of a wicked witch. This nebula’s ‘official’ name is IC 2118, and it is just a cloud of interstellar gas and dust — nothing to be afraid of! The eerie shape is sculpted in part by radiation from the supergiant star Rigel, the brightest star of Orion. In fact, Rigel illuminates the nebula by reflecting off the dust grains, making it glow. Inside the nebula, young stars are being born. This image was taken by a former NASA scientist/engineer Fred Herrmann of the Owl Mountain Observatory near Huntsville, Alabama — ftherrmann2012 on Flickr. You can see an infrared image of this same nebula taken by the WISE spacecraft.
You can see more great images on Universe Today’s Flickr group page (click here to access, or see the new “Photos” tab at the top of our page) and feel free join the group and upload any astronomical images you have taken.
Happy Halloween from all of us here at Universe Today!
The Witch Head nebula is estimated to be hundreds of light-years away in the constellation of Orion. This image was taken by the WISE spacecraft. Credit: NASA.
Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
The SpaceX Dragon capsule is snared by the International Space Station's Canadarm 2. Credit: NASA
SpaceX — the maker and operator of the Dragon spacecraft that runs periodic cargo flights to the International Space Station — has signed a contract to research, develop and test Raptor methane rocket engines at the NASA Stennis Space Center in southern Mississippi.
The California-based company plans to use the E-2 test stand at Stennis, which is able to support both vertical and horizontal rocket engine tests. (Here are some more technical details from NASA on its capabilities.)
“We have been talking with SpaceX for many years about working at Stennis Space Center, and I am pleased to officially welcome them to our Mississippi family. I hope this is just the beginning of their endeavors in our state,” stated U.S. Senator Thad Cochran (R-Miss) in response to the news. A press release from his office said the presence of the private space company would boost jobs in the region.
The E-2 test stand at NASA Stennis Space Center in southern Mississippi. The stand is used for vertical and horizontal rocket engine tests, among other things. Credit: NASA
There’s little information on SpaceX’s website about what the Raptor engine is or specific development plans, but Space News reports that it would be used for deep-space missions. SpaceX CEO Elon Musk has mentioned the engine previously when talking about Mars missions, according to multiple media reports.
“We are looking to test the whole engine at Stennis, but the first phase starts with the components,” SpaceX spokesperson Emily Shanklin said in the Space News report. “The E-2 stand at Stennis is big enough for components, but we would need a bigger stand for the whole Raptor.”
The two sides are reportedly hashing out a Space Act agreement to establish user fees and other parameters. Once that’s finished, the testing will begin, perhaps as early as next year. SpaceX currently does most of its rocket testing in Texas.
Other parties in the agreement — which was signed by Governor Phil Bryant — include the Mississippi Development Authority, the Harbor Commission and Hancock County Port.
Antarctica's sea ice on Sept. 22, 2013. Scientists say there was more ice on the ocean then than in any time in recorded satellite history. Data came from the Advanced Microwave Scanning Radiometer 2 (AMSR2) sensor on Japan’s Global Change Observation Mission 1st-Water (GCOM-W1) satellite. You can see the land in dark gray and ice shelves in light gray. The yellow line represents the average distribution of sea ice between 1981 and 2000. Credit: NASA/Jesse Allen, using data from the Advanced Microwave Scanning Radiometer 2 (AMSR2) sensor on the Global Change Observation Mission 1st-Water (GCOM-W1) satellite.
Antarctica’s sea ice is creeping further out in the ocean! New data from a Japanese satellite shows that sea ice surrounding the southern continent in late September reached out over 7.51 million square miles (19.47 million square kilometers).
The extent — a slight increase over 2012’s record of 7.50 million square miles (19.44 million square km) — is the largest recorded instance of Antarctica sea ice since satellite records began, NASA said. Data was recorded using the Advanced Microwave Scanning Radiometer 2 (AMSR2) sensor on the Global Change Observation Mission 1st-Water (GCOM-W1) satellite.
“While researchers continue to study the forces driving the growth in sea ice extent, it is well understood that multiple factors—including the geography of Antarctica, the region’s winds, as well as air and ocean temperatures—all affect the ice,” NASA stated.
Update — see below for a more detailed description of why this is an important clue that climate change IS happening.
“Geography and winds are thought to be especially important. Unlike the Arctic, where sea ice is confined in a basin, Antarctica is a continent surrounded by open ocean. Since its sea ice is unconfined, it is particularly sensitive to changes in the winds. As noted by the National Snow and Ice Data Center, some research has suggested that changes in Antarctic sea ice are caused in part by a strengthening of the westerly winds that flow unhindered in a circle above the Southern Ocean.”
For those thinking that increased sea ice means we can relax about climate change, this humorous video explains the difference between land ice (glaciers) and sea ice (which is generated from snow, rainfall and fresh water). It’s definitely worth four minutes of your time. The part about sea ice starts around 2:45.
UPDATE: Just to clarify:
Here’s what the graphic says: “The water around Antarctica is more fresh than it has been in previous years because of increased snow and rainfall as well as in increased contribution of fresh water from melting land ice. This fresh cold water is less dense than the warmer, saltier water below. Previously, that warm salty water would rise, melting the sea ice. But now, bcaus of the lighter fresh water on top, there is less mixing of the ocean’s layer and the surface stays cooler longer. “
And so, there is increased fresh water because of the melting land ice – due to climate change. There is a fundamental difference between sea ice and land ice. Antarctic land ice is the ice which has accumulated over thousands of years on the Antarctica landmass through snowfall. Antarctic sea ice is entirely different as it is ice which forms in salt water during the winter and almost entirely melts again in the summer.
Importantly, when land ice melts and flows into the oceans global sea levels rise on average; when sea ice melts sea levels do not change measurably but other parts of the climate system are affected, like increased absorption of solar energy by the darker oceans.
This illustration compares our Earth with the newly confirmed lava planet Kepler-78b. Kepler-78b is about 20 percent larger than Earth, with a diameter of 9,200 miles, and weighs roughly 1.8 times as much as Earth.
David A. Aguilar (CfA)
A newly verified planet found in data from the Kepler mission delivers on the space telescope’s task of finding Earth-size planets around other stars. The new planet, called Kepler-78b, is the first Earth-sized exoplanet discovered that has a rocky composition like that of Earth. Similarities to Earth, however, end there. Kepler-78b whizzes around its host star every 8.5 hours at a distance of about 1.5 million kilometers, making it a blazing inferno and not suitable for life as we know it.
“We’ve been hearing about the sungrazing Comet ISON that will go very close to the Sun next month,” said Andrew Howard, of the University of Hawaii at Manoa’s Institute for Astronomy. “Comet ISON will approach the Sun about the same distance that Kepler-78b orbits its star, so this planet spends its entire life as a sungrazer.”
Howard is the lead author on one of two papers published in Nature that details the discovery of the new planet. He spoke during a media webcast discussing the finding.
“This is a planet that exists but shouldn’t,” added astronomer David Latham of the Harvard-Smithsonian Center for Astrophysics (CfA), also discussing the discovery during the webcast.
Kepler-78b is 1.2 times the size of Earth with a diameter of 14,800 km (9,200 miles) and 1.7 times more massive. As a result, astronomers say it has a density similar to Earth’s, which suggests an Earth-like composition of iron and rock. A handful of planets the size or mass of Earth have been discovered, but Kepler-78b is the first to have both a measured mass and size. With both quantities known, scientists can calculate a density and determine what the planet is made of.
Its star is slightly smaller and less massive than the sun and is located about 400 light-years from Earth in the constellation Cygnus.
However, the close-in orbit of Kepler-78b poses a challenge to theorists. According to current theories of planet formation, it couldn’t have formed so close to its star, nor could it have moved there. Back when this planetary system was forming, the young star was larger than it is now. As a result, the current orbit of Kepler-78b would have been inside the swollen star.
This diagram illustrates the tight orbit of Kepler-78b, which orbits its star every 8.5 hours at a distance of less than a million miles. It is only 2.7 stellar radii from the center of the star, or 1.7 stellar radii from the star’s surface. David A. Aguilar (CfA)
“It couldn’t have formed in place because you can’t form a planet inside a star,” said team member Dimitar Sasselov, also from CfA. “It couldn’t have formed further out and migrated inward, because it would have migrated all the way into the star. This planet is an enigma.”
One idea, suggested Howard, is that the planet is the remnant core of a former gas giant planet, but that turns out to be a problem as well. “We just don’t know what the origin of this planet is,” Howard said.
However, the two teams of planet hunters feel that its existence bodes well for future discoveries of habitable planets.
The two independent research teams used ground-based telescopes for follow-up observations to confirm and characterize Kepler-78b. The team led by Howard used the W. M. Keck Observatory atop Mauna Kea in Hawaii. The other team led by Francesco Pepe from the University of Geneva, Switzerland, did their ground-based work at the Roque de los Muchachos Observatory on La Palma in the Canary Islands.
To determine the planet’s mass, the teams employed the radial velocity method to measure how much the gravitation tug of an orbiting planet causes its star to wobble. Kepler, on the other hand, determines the size or radius of a planet by the amount of starlight blocked when it passes in front of its host star.
“Determining mass of an Earth-sized planet is technically daunting,” Howard said during the webcast, explaining how they used the HIRES (High Resolution Echelle Spectrometer) on Keck. “We pushed HIRES to its limit. The observations were difficult because the star is young with many more star spots (just like sunspots on our Sun) than our Sun, and we have to remove them from our data. But since this planet orbits every eight and a half hours, we were able to watch an entire orbit in one night. We clearly saw the planet’s signal, and we watched it eight different nights.”
David Aguilar from CfA said both teams knew the other team was studying this star, but they didn’t compare their work until both teams were ready to submit their papers so that they wouldn’t influence each other. “It was very encouraging both teams got the same result,” Aguilar said.
Howard also thought having two separate teams work on the same target was great. “We didn’t have to wait for further confirmation of the planet, because the two teams confirmed each other,” he said. “In science, this is as good as it gets.”
Francesco Pepe from the second team said they benefitted from using a twin of the original HARPS (High Accuracy Radial velocity Planet Searcher) which has found nearly 200 exoplanets. “HARPS North at La Palma has the same precision and efficiency as its twin,” Pepe explained during the webcast, “and we decided to guarantee time to follow up on small exoplanet candidates from Kepler. We optimized our observing strategy and we expect many more confirmations in the coming years from this technique.”
As for Kepler-78b, this is a doomed world. Gravitational tides will continue to pull Kepler-78b even closer to its star. Eventually it will move so close that the star’s gravity will rip the world apart. Theorists predict that the planet will vanish within three billion years. Interestingly, astronomers say, our solar system could have held a planet like Kepler-78b. If it had, the planet would have been destroyed long ago leaving no signs for astronomers today.
“We did not detect additional planets in this system,” said Howard, “but we hope to observe this system more in the future.”
We’ve talked about Venus, the hottest planet in the Solar System, but we know things can get pretty hot here on Earth, too. You may be wondering, where on the surface of the Earth has the highest natural temperature been recorded?
The location of this world record has had some controversy, but as of 2013, the hottest spot on record was the Furnace Creek Ranch in California’s Death Valley. On July 10, 1913, weather instruments measured 56.7 degrees Celsius, or 134 degrees Fahrenheit.
The previous record of 56 degrees at El Azizia, Libya was overturned because a systematic study in 2012 discovered there were errors in the measuring methods.
Similar temperatures to Death Valley’s record have been recorded around the World:
55 degrees in Africa,
53.6 in Asia,
50.7 in Australia,
and 49.1 in Argentina.
But these are just measurements from weather stations. It’s likely there are hotter temperatures, but nobody was around to measure. NASA satellites have spotted regions in Iran’s Lut desert which might have reached 70 degrees Celsius during the summers of 2004 and 2005.
So that’d be the hottest spot on the surface, but what about the hottest natural spot anywhere in the entire planet? Now you’ve got to travel straight down 6,371 kilometers to the very center of the Earth. At the inner core, the temperatures rise to about 5,430 degrees C, or 5700 Kelvin. Amazingly, this is about the same temperature as the surface of the Sun.
Some of this high temperature comes from leftover heat from the formation of the planet, 4.54 billion years ago, but the vast majority comes from the decay of radioactive minerals inside the Earth. It was likely hotter in the past, but all the short-period isotopes have already been depleted.
I keep saying the word “natural”, but what about “unnatural”? Wondering about the hottest temperature EVER generated on Earth? Thermonuclear explosions reach temperatures of tens of millions of Kelvin. Fusion experiments have hit 500 million Kelvin. But that’s nothing.
In 2012, physicists working with the Large Hadron Collider were investigating the conditions that might have existed during the earliest moments of the Big Bang.
They generated a quark gluon plasma that had a temperature of 5.5 trillion Kelvin.
Unless aliens can do better, this is not only the hottest temperature ever recorded on Earth, it’s easily the hottest temperature anywhere in the Universe since the Big Bang itself.
The Hubble Space Telescope image of the inner regions of the lensing cluster Abell 1689 that is 2.2 billion light?years away. Light from distant background galaxies is bent by the concentrated dark matter in the cluster (shown in the blue overlay) to produce the plethora of arcs and arclets that were in turn used to constrain dark energy. Image courtesy of NASA?ESA, Jullo (JPL), Natarajan (Yale), Kneib (LAM)
We keep saying dark matter is so very hard to find. Astronomers say they can see its effects — such as gravitational lensing, or an amazing bendy feat of light that takes place when a massive galaxy brings forward light from other galaxies behind it. But defining what the heck that matter is, is proving elusive. And considering it makes up most of the universe’s matter, it would be great to know what dark matter looks like.
A new experiment — billed as the most sensitive dark matter detector in the world — spent three months searching for evidence of weakly interacting massive particles (WIMPs), which may be the basis of dark matter. So far, nothing, but researchers emphasized they have only just started work.
“Now that we understand the instrument and its backgrounds, we will continue to take data, testing for more and more elusive candidates for dark matter,” stated physicist Dan McKinsey of Yale University, who is one of the collaborators on the Large Underground Xenon (LUX) detector.
A view of the Large Underground Xenon (LUX) dark matter detector. Shown are photomultiplier tubes that can ferret out single photons of light. Signals from these photons told physicists that they had not yet found Weakly Interacting Massive Particles (WIMPs) Credit: Matthew Kapust / South Dakota Science and Technology Authority
LUX operates a mile (1.6 kilometers) beneath the Earth in the state-owned Sanford Underground Research Facility, which is located in South Dakota. The underground location is perfect for this kind of work because there is little interference from cosmic ray particles.
“At the heart of the experiment is a six-foot-tall titanium tank filled with almost a third of a ton of liquid xenon, cooled to minus 150 degrees Fahrenheit. If a WIMP strikes a xenon atom it recoils from other xenon atoms and emits photons (light) and electrons. The electrons are drawn upward by an electrical field and interact with a thin layer of xenon gas at the top of the tank, releasing more photons,” stated the Lawrence Berkeley National Laboratory, which leads operations at Sanford.
“Light detectors in the top and bottom of the tank are each capable of detecting a single photon, so the locations of the two photon signals – one at the collision point, the other at the top of the tank – can be pinpointed to within a few millimeters. The energy of the interaction can be precisely measured from the brightness of the signals.”
The densest regions of the dark matter cosmic web host massive clusters of galaxies. Credit: Van Waerbeke, Heymans, and CFHTLens collaboration.
LUX’s sensitivity for low-mass WIMPs is more than 20 times better than other detectors. That said, the detector was unable to confirm possible hints of WIMPs found in other experiments.
“Three candidate low-mass WIMP events recently reported in ultra-cold silicon detectors would have produced more than 1,600 events in LUX’s much larger detector, or one every 80 minutes in the recent run,” the laboratory added.
Don’t touch that dial yet, however. LUX plans to do more searching in the next two years. Also, the Sanford Lab is proposing an even more sensitive LUX-ZEPLIN experiment that would be 1,000 times more sensitive than LUX. No word yet on when LUX-ZEPLIN will get off the ground, however.
