A graphic designer in Rhode Island, Jason writes about space exploration on his blog Lights In The Dark, Discovery News, and, of course, here on Universe Today. Ad astra!
Hubble image of SNR 0519, the remains of a Type Ia supernova in the Large Magellanic Cloud
Stars like our Sun can last for a very long time (in human terms, anyway!) somewhere in the neighborhood of 10-12 billion years. Already over 4.6 billion years old, the Sun is entering middle age and will keep on happily fusing hydrogen into helium for quite some time. But eventually even stars come to the end of their lives, and their deaths are some of the most powerful — and beautiful — events in the Universe.
The wispy, glowing red structures above are the remains of a white dwarf in the neighboring Large Magellanic Cloud 150,000 light-years away. Supernova remnant SNR 0519 was created about 600 years ago (by our time) when a star like the Sun, in the final stages of its life, gathered enough material from a companion to reach a critical mass and then explode, casting its outer layers far out into space to create the cosmic rose we see today.
As the hydrogen material from the star plows outwards through interstellar space it becomes ionized, glowing bright red.
SNR 0519 is the result of a Type Ia supernova, which are the result of one white dwarf within a binary pair drawing material onto itself from the other until it undergoes a core-collapse and blows apart violently. The binary pair can be two white dwarfs or a white dwarf and another type of star, such as a red giant, but at least one white dwarf is thought to always be the progenitor.
A recent search into the heart of the remnant found no surviving post-main sequence stars, suggesting that SNR 0519 was created by two white dwarfs rather than a mismatched pair. Both stars were likely destroyed in the explosion, as any non-degenerate partner would have remained.
A hole from a meteorite in the Space Station's solar array
Canadian astronaut and Expedition 35 commander Chris Hadfield just shared this photo on Twitter, showing a portion of one of the solar array wings on the ISS… with a small but very visible hole made by a passing meteoroid in one of the cells.
In typical poetic fashion, Commander Hadfield referred to the offending object as “a small stone from the universe.”
“Glad it missed the hull,” he added.
Hole in an ISS solar cell made by a meteoroid
While likened to a bullet hole, whatever struck the solar panel was actually traveling much faster when it hit. Most bullets travel at a velocity of around 1,000-2,000 mph (although usually described in feet per second) but meteoroids are traveling through space at speeds of well over 25,000 mph — many times faster than any bullet!
Luckily the ISS has a multi-layered hull consisting of layers of different materials (depending on where the sections were built), providing protection from micrometeorite impacts. If an object were to hit an inhabited section of the Station, it would be slowed down enough by the different layers to either not make it to the main hull or else merely create an audible “ping.”
Unnerving, yes, but at least harmless. Still, it’s a reminder that the Solar System is still very much a shooting gallery and our spacefaring safety relies on the use of technology to protect ourselves.
Image: NASA / Chris Hadfield
Fact: The 110 kilowatts of power for the ISS is supplied by an acre of solar panels!
Saunders Island and Wolstenholme Fjord with Kap Atholl in the background photographed during a NASA IceBridge flight. (NASA/Michael Studinger)
It’s quite a long way from Mars, but I can’t help but be reminded of the Red Planet’s ice-covered north pole when looking at this photo taken by Michael Studinger earlier this month, during a recent IceBridge survey flight over Greenland.
Called Saunders Island (also Appat Island) the 82-square-mile frozen slab of rock rises from the sea off the coast of northwestern Greenland, one of many islands within the Wolstenholme (Uummannaq) Fjord on the shore of Baffin Bay. Operation IceBridge, a six-year aerial survey of the changing ice coverage at our planet’s poles, is run by NASA to provide valuable ground-level information to supplement satellite data.
To me, the shape of the island’s steep rock faces and rugged inlets slice into its interior bear a striking resemblance to Mars’ ice cap.
Mars’ north polar ice cap
While Mars’ ice cap is shaped by very different processes — and obviously much bigger — you might see the connection too!
But rather than dark Martian dunes, sea ice can be seen surrounding the islands in varying thicknesses in the IceBridge photo above. Sea ice coverage in the fjord ranges from thicker, white ice in the background to thinner “grease” ice and leads with dark, open ocean water in the foreground.
The IceBridge P-3B airborne laboratory in a hangar at Wallops Flight Facility (NASA/George Hale)
As the amount of darker, ice-free water surfaces increase over the course of the year due to rising global temperatures, the more heat from solar radiation is collected in the ocean — thus speeding up the process of seasonal sea ice loss and overall Arctic warming.
Read more about the IceBridge mission here, and see a collection of more photos from this season’s flights here.
NASA’s Operation IceBridge images Earth’s polar ice in unprecedented detail to better understand processes that connect the polar regions with the global climate system. IceBridge utilizes a highly specialized fleet of research aircraft and the most sophisticated suite of innovative science instruments ever assembled to characterize annual changes in thickness of sea ice, glaciers, and ice sheets. In addition, IceBridge collects critical data used to predict the response of earth’s polar ice to climate change and resulting sea-level rise.
A long, magnetic filament burst out from the Sun after a C-cladd flare on(Aug. 31, 2012 (NASA/SDO/AIA)
We live on a planet dominated by weather. But not just the kind that comes in the form of wind, rain, and snow — we are also under the influence of space weather, generated by the incredible power of our home star a “mere” 93 million miles away. As we orbit the Sun our planet is, in effect, inside its outer atmosphere, and as such is subject to the constantly-flowing wind of charged particles and occasional outbursts of radiation and material that it releases. Although it may sound like something from science fiction, space weather is very real… and the more we rely on sensitive electronics and satellites in orbit, the more we’ll need to have accurate weather reports.
Fortunately, the reality of space weather has not gone unnoticed by the U.S. Federal Government.
An X1.6 flare eruption on Jan. 27, 2012 (NASA/SDO/AIA)
Today the White House Office of Science and Technology Policy released a new report, Space Weather Observing Systems: Current Capabilities and Requirements for the Next Decade, which is an assessment of the United States government’s capacity to monitor and forecast potentially harmful space weather and how to possibly mitigate the damage from any exceptionally powerful solar storms in the future.
The report was made by a Joint Action Group (JAG) formed by the National Space Weather Program Council (NSWPC).
The impacts of space weather can have serious economic consequences. For example, geomagnetic storms during the 1990’s knocked out several telecommunications satellites, which had to be replaced at a cost of about $200 million each. If another “once in a century” severe geomagnetic storm occurs (such as the 1859 “super storm”), the cost on the satellite industry alone could be approximately $50 – $100 billion. The potential consequences on the Nation’s power grid are even higher, with potential costs of $1 – 2 trillion that could take up to a decade to completely repair.
– Report on Space Weather Observing Systems: Current Capabilities and Requirements for the Next Decade (April 2013)
“In other words,” according to the report, “the Nation is at risk of losing critical capabilities that have significant economic and security impacts should these key space weather observing systems fail to be maintained and replaced.”
The National Space Weather Program is a Federal interagency initiative with the mission of advancing the improvement of space weather services and supporting research in order to prepare the country for the technological, economic, security, and health impacts that may arise from extreme space weather events.
A close "peak of eternal light" (PEL) near Mercury's south pole
Mercury, traveling in its 88-day-long orbit around the Sun with basically zero axial tilt, has many craters at its poles whose insides literally never see the light of day. These permanently-shadowed locations have been found by the MESSENGER mission to harbor considerable deposits of ice (a seemingly ironic discovery on a planet two-and-a-half times closer to the Sun than we are!*)
But if there are places on Mercury where the Sun never shines (insert butt joke here) then there may also be places where it always does. That’s what researchers are looking for in illumination maps made from MESSENGER data… and they’re getting closer.
The image above shows a region near Mercury’s south pole. The yellow arrow points to the closest thing to a true “peak of eternal light” found thus far on Mercury, a point that receives sunlight about 82% of the time — almost constantly illuminated.
Studies of the illumination conditions near the north and south poles of Mercury are of interest because they can be used to determine locations of permanent shadow, extremely cold places where ice deposits lurk. However, the illumination maps also reveal the locations that receive the maximum duration of sunlight during a Mercury solar day.
A “peak of eternal light” that is illuminated continuously for an entire solar day would be a favorable target for a lander, because solar power would be available all the time. So far, no such peak of eternal light has been identified at Mercury’s south pole.
The spot that get the most illumination (about 82%), is located at 89° S, 50.7° E.
This image was acquired as part of MDIS’s campaign to monitor the south polar region of Mercury. By imaging the polar region approximately every four MESSENGER orbits as illumination conditions change, features that were in shadow on earlier orbits can be discerned and any permanently shadowed areas can be identified after repeated imaging over one solar day.
Illumination map of Mercury’s south polar region (Pub. March 2012)
“A ‘peak of eternal light’ that is illuminated continuously for an entire solar day would be a favorable target for a lander, because solar power would be available all the time.”
The top image above was acquired on Dec. 24, 2011. The large crater is Chao Meng-Fu, about 129 km (80 mi.) in diameter. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.
*Without an atmosphere to hold and distribute heat, any place on Mercury that stays in shadow for any length of time will remain very cold — plenty cold enough for water ice to remain rock-hard indefinitely.
Daphnis' gravity disturbs the edges of the Keeler Gap as it travels along
Captured on January 15, this narrow-angle Cassini image shows an outer portion of Saturn’s A ring on the left and the ropy F ring crossing on the right. The thin black line near the A ring’s bright edge is the Keeler Gap, a 22-mile-wide space cleared by the passage of Daphnis, a shepherd moon barely 5 miles (about 7.5 km) across. As it travels around Saturn within the gap its gravity perturbs the fine icy particles within the rings, sending up rippling waves both before and behind it — visible here near the upper center.
From Cassini’s distance of 870,000 miles (1.4 million km) Daphnis itself is just barely visible as a single pixel within the Gap — can you see it? If not, click below…
There it is:
Highlighting Daphnis inside the Keeler Gap
While lacking the murky mystery of Titan’s atmosphere, Enceladus’ dramatic jets and the tortured and cratered surfaces found on Dione, Rhea, Mimas and many of Saturn’s larger icy moons, little Daphnis has always fascinated me because of the scalloped waves it kicks up within Saturn’s rings. Eventually these waves settle back down, but at their highest they can extend a mile or two above and below the ring plane!
Daphnis’ wake casts peaked shadows on the rings
This effect was most pronounced during Saturn’s spring equinox in August 2009 when sunlight was striking the rings edge-on, creating strong shadows from any areas of relief.
Imagine the impressive view you’d have if you were nearby, positioned just above the rings as Daphnis approached and hurtled past, the rings rising up in mile-high peaks from the moon’s gravity before smoothing out again. Incredible!
Daphnis seen by Cassini in June 2010 (NASA/JPL/SSI)
And I’m not the only one to imagine such a scene either — apparently artist Erik Svensson is also intrigued by Daphnis, enough to have been inspired to create the image below. How very cool!
Like its larger shepherd moon sister Prometheus, Daphnis may be little but still has a big effect on the icy stuff that makes up Saturn’s iconic rings.
And for lots more views of Daphnis click here (but watch out, it may just become your favorite moon too!)
Image credits: NASA/JPL-Caltech/Space Science Institute.
Composite Spitzer, Hubble, and Chandra image of supernova remnant Cassiopeia A. A new study shows that a supernova as far away as 50 light years could have devastating effects on life on Earth. (NASA/JPL-Caltech/STScI/CXC/SAO)
“The total number of stars in the Universe is larger than all the grains of sand on all the beaches of the planet Earth,” Carl Sagan famously said in his iconic TV series Cosmos. But when two of those grains are made of a silicon-and-oxygen compound called silica, and they were found hiding deep inside ancient meteorites recovered from Antarctica, they very well may be from a star… possibly even the one whose explosive collapse sparked the formation of the Solar System itself.
Researchers from Washington University in St. Louis with support from the McDonnell Center for the Space Sciences have announced the discovery of two microscopic grains of silica in primitive meteorites originating from two different sources. This discovery is surprising because silica — one of the main components of sand on Earth today — is not one of the minerals thought to have formed within the Sun’s early circumstellar disk of material.
Instead, it’s thought that the two silica grains were created by a single supernova that seeded the early solar system with its cast-off material and helped set into motion the eventual formation of the planets.
According to a news release by Washington University, “it’s a bit like learning the secrets of the family that lived in your house in the 1800s by examining dust particles they left behind in cracks in the floorboards.”
A 3.5-cm chondrite meteorite found in Antarctica in Nov. 1998. Dark meteorites show up well against the icy terrain of Antarctica. (Carnegie Mellon University)
Until the 1960s most scientists believed the early Solar System got so hot that presolar material could not have survived. But in 1987 scientists at the University of Chicago discovered miniscule diamonds in a primitive meteorite (ones that had not been heated and reworked). Since then they’ve found grains of more than ten other minerals in primitive meteorites.
The scientists can tell these grains came from ancient stars because they have highly unusual isotopic signatures, and different stars produce different proportions of isotopes.
But the material from which our Solar System was fashioned was mixed and homogenized before the planets formed. So all of the planets and the Sun have the pretty much the same “solar” isotopic composition.
Meteorites, most of which are pieces of asteroids, have the solar composition as well, but trapped deep within the primitive ones are pure samples of stars, and the isotopic compositions of these presolar grains can provide clues to their complex nuclear and convective processes.
The layered structure of a star about to go supernova; different layers contain different elements (Wikimedia)
Some models of stellar evolution predict that silica could condense in the cooler outer atmospheres of stars, but others say silicon would be completely consumed by the formation of magnesium- or iron-rich silicates, leaving none to form silica.
“We didn’t know which model was right and which was not, because the models had so many parameters,” said Pierre Haenecour, a graduate student in Earth and Planetary Sciences at Washington University and the first author on a paper to be published in the May 1 issue of Astrophysical Journal Letters.
Under the guidance of physics professor Dr. Christine Floss, who found some of the first silica grains in a meteorite in 2009, Haenecour investigated slices of a primitive meteorite brought back from Antarctica and located a single grain of silica out of 138 presolar grains. The grain he found was rich in oxygen-18, signifying its source as from a core-collapse supernova.
Finding that along with another oxygen-18-enriched silica grain identified within another meteorite by graduate student Xuchao Zhao, Haenecour and his team set about figuring out how such silica grains could form within the collapsing layers of a dying star. They found they could reproduce the oxygen-18 enrichment of the two grains through the mixing of small amounts of material from a star’s oxygen-rich inner zones and the oxygen-18-rich helium/carbon zone with large amounts of material from the outer hydrogen envelope of the supernova.
In fact, Haenecour said, the mixing that produced the composition of the two grains was so similar, the grains might well have come from the same supernova — possibly the very same one that sparked the collapse of the molecular cloud that formed our Solar System.
“It’s a bit like learning the secrets of the family that lived in your house in the 1800s by examining dust particles they left behind in cracks in the floorboards.”
Ancient meteorites, a few microscopic grains of stellar sand, and a lot of lab work… it’s an example of cosmic forensics at its best!
Do you know how much material falls onto Earth from space every day? How many different species there are in the ocean? How far the continents move every year? In honor of Earth Day here’s a very cool infographic that answers those questions about our planet — and 47 more!
Check out the full version below:
And for more interesting information about our planet, click here and here.
Dr. Sally Ride, the first American woman to fly in space
Dr. Sally K. Ride, physicist, NASA astronaut, and first American woman to fly in space, will be honored with a U.S. Navy research vessel bearing her name, which will be operated by and homeported at San Diego’s Scripps Institution of Oceanography.
“Dr. Sally Ride inspired millions of people, especially young women and girls, to reach for the stars,” said U.S. Sen. Barbara Boxer, D-Calif. “Naming the Navy’s new ocean research vessel in her honor is a fitting tribute to her legacy of innovation and discovery.”
Dr. Ride died at her home in La Jolla on July 23, 2012, after a 17-month battle with pancreatic cancer. She was 61.
Sally Ride was a NASA astronaut for 11 years before joining the UCSD faculty as a physics professor and director of the California Space Institute.
Dr. Ride was selected for NASA’s astronaut corps in 1978 and became the first American woman in space aboard Space Shuttle Challenger in 1983. In 1989, she joined the faculty of UC San Diego as professor of physics and was director of the university’s California Space Institute.
“We are touched by the extraordinary honor that this ship is being named for Sally Ride, who, after serving our nation as a pioneering and accomplished astronaut, served on the faculty of UC San Diego for nearly two decades,” said UC San Diego Chancellor Pradeep K. Khosla in a Scripps press release. “Her commitment to teaching and inspiring young minds is legendary and we take tremendous pride in this prestigious and well-deserved honor for her legacy and for UC San Diego.”
According to Gary Robbins in an article for the San Diego Union-Tribune “It is common for a research vessel to be named after an explorer or scientist. Scripps’ current fleet of Navy-owned ships includes the Roger Revelle, which bears the name of the late UC San Diego scientist who helped pioneer the study of global warming. The Woods Hole Oceanographic Institution in Cape Cod, Mass. is getting a ship named R/V Neil Armstrong.”
Rendering of the R/V Sally Ride
Designed to operate globally, R/V Sally Ride will continue the Scripps legacy of conducting pioneering ocean exploration and research critical to our understanding of our planet, our oceans, and our atmosphere. As a shared-use, general-purpose ship, R/V Sally Ride will engage in a broad spectrum of research in physics, chemistry, biology, geology, and climate science, including research missions with relevance to the Navy.
As a seagoing laboratory supporting research and education, the new ship will feature modern research instrumentation to fuel scientific exploration, including mapping systems, sensors, and profilers that will investigate features from the seafloor to the atmosphere.
“I can’t think of a more perfect name for the Navy’s new research vessel. Dr. Ride was a trailblazer in every sense of the word in the fields of science and engineering. Dr. Ride’s namesake ship and its crew will continue her legacy of courage, determination, and spirit of discovery.”
– U.S. Rep. Susan Davis, D-Calif.
R/V Sally Ride is currently under construction at Dakota Creek Industries Inc. in Anacortes, Washington, and is scheduled for launch in 2015.
The international Super Cryogenic Dark Matter Search (SuperCDMS) has detected what may be the particle that's thought to make up dark matter throughout the Universe.
Dark matter: it’s invisible, it’s elusive, it’s controversial… and it’s everywhere — in the Universe, yes, but especially in the world of astrophysics, where researchers have been exhaustively trying to reveal its true identity for decades.
Now, scientists with the international Super Cryogenic Dark Matter Search (SuperCDMS) experiment are reporting the detection of a particle that’s thought to make up dark matter: a weakly-interacting massive particle, or WIMP. According to a press release from Texas A&M University (whose high-energy physicist Rupak Mahapatra is a principal investigator in the experiment) SuperCDMS has identified a WIMP-like signal at the 3-sigma level, which indicates a 99.8 percent chance of an actual discovery — a “concrete hint,” as it’s being called.
“In high-energy physics, a discovery is only claimed at 5-sigma or better,” Mahapatra said. “So this is certainly very exciting, but not fully convincing by the standards. We just need more data to be sure. For now, we have to live with this tantalizing hint of one of the biggest puzzles of our time.”
If this is indeed a WIMP it will be the first time such a particle has been directly observed, lending more insight into what dark matter is… or isn’t.
Notoriously elusive, WIMPs rarely interact with normal matter and therefore are difficult to detect. Scientists believe they occasionally bounce off, or scatter like billiard balls from, atomic nuclei, leaving behind a small amount of energy capable of being tracked by detectors deep underground, particle colliders such as the Large Hadron Collider at CERN and even instruments in space like the Alpha Magnetic Spectrometer (AMS) mounted on the International Space Station.
A stack of crystal germanium CDMS detectors (Fermilab)
The CDMS experiment, located a half-mile underground at the Soudan mine in northern Minnesota and managed by the United States Department of Energy’s Fermi National Accelerator Laboratory, has been searching for dark matter since 2003. The experiment uses very sophisticated detector technology and advanced analysis techniques to enable cryogenically cooled (almost absolute zero temperature at -460 degrees F) germanium and silicon targets to search for the rare recoil of dark matter particles.
This newly-announced detection actually comes from data acquired during an earlier phase of the experiment.
“This result is from data taken a few years ago using silicon detectors manufactured at Stanford that are now defunct,” Mahapatra said. “Increased interest in the low mass WIMP region motivated us to complete the analysis of the silicon-detector exposure, which is less sensitive than germanium for WIMP masses above 15 giga-electronvolts [one GeVa is equal to a billion electron volts] but more sensitive for lower masses. The analysis resulted in three events, and the estimated background is 0.7 events.”
Although Mahapatra says the result is certainly encouraging and worthy of further investigation, he cautions it should not be considered a discovery just yet.
“We are only 99.8 percent sure, and we want to be 99.9999 percent sure,” Mahapatra said. “At 3-sigma, you have a hint of something. At 4-sigma, you have evidence. At 5-sigma, you have a discovery.”
“In medicine, you can say you are curing 99.8 percent of the cases, and that’s OK. When you say you’ve made a fundamental discovery in high-energy physics, you can’t be wrong.”
– Dr. Rupak Mahapatra, SuperCDMS principal investigator, Texas A&M University
Advanced 6-inch silicon detectors developed by Mahapatra’s lab at Texas A&M
The collaboration will continue to probe this WIMP sector using the SuperCDMS Soudan experiment’s operating germanium detectors and is considering using larger, more advanced 6-inch silicon detectors developed at the Texas A&M’s Department of Electrical Engineering in future experiments.
The team has detailed its results in a paper published in arXiv that eventually will appear in Physical Review Letters. Mahapatra will also announce the results today at 12 p.m. CDT in a talk at the Mitchell Institute for Fundamental Physics and Astronomy.
