Posted on by Jason Major

X-ray Burst May Be the First Sign of a Supernova

GRB 080913, a distant supernova detected by Swift. This image merges the view through Swift’s UltraViolet and Optical Telescope, which shows bright stars, and its X-ray Telescope. Credit: NASA/Swift/Stefan Immler

The first moments of a massive star going supernova may be heralded by a blast of x-rays, detectable by space telescopes like Swift, which could then tell astronomers where to look for the full show in gamma rays and optical wavelengths. These findings come from the University of Leicester in the UK where a research team was surprised by the excess of thermal x-rays detected along with gamma ray bursts associated with supernovae.

“The most massive stars can be tens to a hundred times larger than the Sun,” said Dr. Rhaana Starling of the University of Leicester  Department of Physics and Astronomy. “When one of these giants runs out of hydrogen gas it collapses catastrophically and explodes as a supernova, blowing off its outer layers which enrich the Universe.

“But this is no ordinary supernova; in the explosion narrowly confined streams of material are forced out of the poles of the star at almost the speed of light. These so-called relativistic jets give rise to brief flashes of energetic gamma-radiation called gamma-ray bursts, which are picked up by monitoring instruments in space, that in turn alert astronomers.”

Powerful gamma ray bursts — GRBs — emitted from supernovae can be detected by both ground-based observatories and NASA’s Swift telescope. Within seconds of detecting a burst (hence its name) Swift relays its location to ground stations, allowing both ground-based and space-based telescopes around the world the opportunity to observe the burst’s afterglow.

But the actual moment of the star’s collapse, when its collapsing core reacts with its surface, isn’t observed — it happens too quickly, too suddenly. If these “shock breakouts” are the source of the excess thermal x-rays (a.k.a. black body emission) that have been recently identified in Swift data, some of the galaxy’s most energetic supernovae could be pinpointed and witnessed at a much earlier moment in time — literally within the first seconds of their birth.

“This phenomenon is only seen during the first thousand seconds of an event, and it is challenging to distinguish it from X-ray emission solely from the gamma-ray burst jet,” Dr. Starling said. “That is why astronomers have not routinely observed this before, and only a small subset of the 700+ bursts we detect with Swift show it.”

Read more: Finding the Failed Supernovae

More observations will be needed to determine if the thermal emissions are truly from the initial collapse of stars and not from the GRB jets themselves. Even if the x-rays are determined to be from the jets it will provide valuable insight to the structure of GRBs… “but the strong association with supernovae is tantalizing,” according to Dr. Starling.

Read more on the University of Leicester press release here, and see the team’s paper in the Nov. 28 online issue of the Monthly Notices of the Royal Astronomical Society here (Full PDF on arXiv.org here.)

Inset image: An artist’s rendering of the Swift spacecraft with a gamma-ray burst going off in the background. Credit: Spectrum Astro. Find out more about the Swift telescope’s instruments here.

 

Posted on by Jason Major

Do We Really Need Dark Matter?

Hubble mosaic of massive galaxy cluster MACS J0717.5+3745, thought to be connected by a filament of dark matter. Credit: NASA, ESA, Harald Ebeling (University of Hawaii at Manoa) & Jean-Paul Kneib (LAM)

Even though teams of scientists around the world are at this very moment hot on the trail of dark matter — the “other stuff” that the Universe is made of and supposedly accounts for nearly 80% of the mass that we can’t directly observe (yet) —  and trying to quantify exactly how so-called “dark energy” drives its ever-accelerating expansion, perhaps one answer to these ongoing mysteries is maybe they don’t exist at all.

This is precisely what one astronomer is suggesting in a recent paper, submitted Dec. 3 to Astrophysical Journal Letters.

In a paper titled “An expanding universe without dark matter and dark energy” (arXiv:1212.1110) Pierre Magain, a professor at Belgium’s Institut d’Astrophysique et de Géophysique, proposes that the expansion of the Universe could be explained without the need for enigmatic material and energy that, to date, has yet to be directly measured.

In addition, Magain’s proposal puts a higher age to the Universe than what’s currently accepted. With a model that shows a slower expansion rate during the early Universe than today, Magain’s calculations estimate its age to be closer to 15.4 – 16.5 billion years old, adding a couple billion more candles to the cosmic birthday cake.

The benefit to a slightly older Universe, Magain posits, is that it’s not so uncannily close to the apparent age of the most distant galaxies recently found — such as MACS0647-JD, which is 13.3 billion light-years away and thus (based on current estimates, see graphic at right) must have formed when the Universe was a mere 420 million years old.

Read more: Now Even Further: Ancient Galaxy is Latest Candidate for Most Distant

Using accepted physics of how time behaves based on Einstein’s theory of general relativity — namely, how the passage of time is relative to the position and velocity of the viewer (as well as the intensity of the gravitational field the viewer is within) — Magain’s model allows for an observer located within the Universe to potentially be experiencing a different rate of time than a hypothetical viewer located outside the Universe. Not to be so metaphysical as to presume that there are external observers of our Universe but merely to say that an external point would be a fixed one against which one could benchmark a varying passage of time inside the Universe, Magain calls this universal relativity.

A viewer experiencing universal relativity would, Magain claims, always measure the curvature of the Universe to be equal to zero. This is what’s currently observed, a “flatness problem” that Magain insinuates is strangely coincidental.

By attributing an expanding Universe to dark energy and the high velocities of stars along the edges of galaxies (as well as the motions of galaxy clusters themselves) to dark matter, we may be introducing ad hoc elements to the Universe, says Magain. Instead, he proposes his “more economical” model — which uses universal relativity — explains these apparently accelerating, increasingly expanding behaviors… and gives a bigger margin of time between the Big Bang and the formation of the first galactic structures.

Read more: First Images in a New Hunt for Dark Energy

There’s quite a bit of math involved, and since I never claimed to understand physics equations you can check out the original paper here.

While intriguing, the bottom line is that dark energy and dark matter have still managed to elude science, existing just outside the borders of what can be observed (although the gravitational lensing effects of what’s thought to be dark matter filaments have been observed by Hubble) and Magain’s paper is merely putting another idea onto the table — one that, while he recognizes needs further testing and relies upon very specific singular parameters, doesn’t depend upon invisible, unobservable and mysteriously dark “stuff”. Whether it belongs on the table or not will be up to other astrophysicists to decide.

Prof. Magain’s research was supported by ESA and the Belgian Science Policy Office.

At right: Artist’s impression of dark matter (h/t to Steve Nerlich)

Note: this is “just” a submitted paper and has not been selected for publication yet. Any hypotheses proposed are those of the author and are not endorsed by this site. (Personally I like dark matter. It’s fascinating stuff… even if we can’t see it. Want an astrophysicist’s viewpoint on the existence of dark matter? Check out Ethan Siegel’s blog response here.)

Posted on by Nancy Atkinson

Apollo 17: 40 Years Ago Today

The launch of Apollo 17. Credit: NASA

It was the end of an era. At 12:33 a.m. (EST) on Dec. 7, 1972 the monstrous Saturn V rocket blasted off for the final Apollo mission to the Moon. It was a stunning sight, as it was the first nighttime liftoff of the Saturn V. Aboard the Apollo 17 spacecraft were astronauts Gene Cernan, Ron Evans and Jack Schmitt.

Below are a couple of images and videos from the mission, one video is an overview of the mission, and the other is one of my favorite scenes:

Gene Cernan driving the lunar rover during the Apollo 17 mission on the Moon. Credit: NASA

Jack Schmitt with the lunar rover at the edge of Shorty Crater. Credit: NASA

The famous “Blue Marble” image of Earth taken by the Apollo 17 crew on Dec. 7, 1972. Credit: NASA

Posted on by Nancy Atkinson

Curiosity Update: Wrapping Up Rocknest

Here’s the latest video update from the MSL science team on Curiosity’s activities. It really just wraps up and recaps our article from earlier this week — that all of Curiosity’s science instruments are now fully up and running, that they found materials on Mars that have been seen by other missions, and they are still looking at some interesting carbon compounds. Also, Ashwin Vasavada reiterates what the science team said on Monday at the press conference: They’re doing science at the speed of science, and no one image or data point will cause us to re-write our science books.

Overhead map of Curiosity’s traverses. Credit: NASA/JPL/University of Arizona

As for what the rover will do next, a couple team members Tweeted today that the rover’s wake up song today was “Should I Stay or Should I Go.” Curiosity is now finishing up at observations at an area called Point Lake; they’ll do some surveys of they another area called Yellowknife Bay, and in the next couple of weeks, do some drive-by imaging, perhaps use ChemCam, and the team said they would really like to find a target for the first use of Curiosity’s drill before the holidays start here on Earth.

Posted on by Nancy Atkinson

“Overview:” The Perspective-Altering Effect of Seeing Earth from Space

For over 40 years, the ‘Blue Marble’ images of Earth taken from space have provided a new perspective of our planet, and the sometimes life-altering experience of such views was described in Frank White’s book “The Overview Effect,” published in 1987. When it came out, I gobbled it up, and have since read it several times.

Today, on the 40th anniversary of the final launch of the Apollo missions to the Moon, a new short film “Overview” has been released, which explores this phenomenon through interviews with five astronauts who have experienced first-hand seeing Earth from space.

“This view of the Earth from space – the whole Earth perspective – is, I think, the true symbol of this age,” says White in the film. “I believe … there’s going to be a greater and greater interest in communicating this idea because, after all, it’s key to our survival. We have to start acting as one species with one destiny. We are not going to survive if we don’t do that.”

The film is an inspiring look at how exploring space has given us look back at our own world and changed our perceptions. While some may say the Overview Effect is only a concept, an ideal outcome of space exploration that has yet to become a global phenomenon, I believe it is certainly something we should strive for.

The Blue Marble image from Apollo 17. Credit: Image courtesy NASA Johnson Space Center. See more info about it here.

The film includes:
Edgar Mitchell – Apollo 14 astronaut and founder of the Institute of Noetic Sciences
Ron Garan – ISS astronaut and founder of humanitarian organization Fragile Oasis
Nicole Stott – Shuttle and ISS astronaut and member of Fragile Oasis
Jeff Hoffman – Shuttle astronaut and senior lecturer at MIT
Shane Kimbrough – Shuttle/ISS astronaut and Lieutenant Colonel in the US Army
Frank White – space theorist and author of the book ‘The Overview Effect’
David Loy- philosopher and author
David Beaver – philosopher and co-founder of The Overview Institute

It was produced by a group called Planetary Collective, specifically Guy Reid, Steve Kennedy and Christopher Ferstad.

OVERVIEW from Planetary Collective on Vimeo.

Posted on by Nancy Atkinson

Golden Spike to Offer Commercial Human Missions to the Moon

A proposed Golden Spike lunar lander on the Moon. Credit: Golden Spike Company

A proposed Golden Spike lunar lander on the Moon. Credit: Golden Spike Company

A group of space experts, media figures and even politicians announced today a new commercial company to bring paying passengers to the Moon. The Golden Spike Company is looking to “implement and operate a human space transportation system at commercially successful price points,” the company says on their website, focusing “on generating a sustainable human lunar exploration business that generates profits through multiple high value revenue streams.”

Initial estimates for a ticket to the Moon and back with Golden Spike are a cool $1.5 billion. But they aren’t only focusing on individuals as paying customers, but also other space companies and even governmental entities.

The people behind Golden Spike include their CEO Alan Stern, Principal Investigator for the New Horizons mission to Pluto who is also involved with several other space-related ventures such as Uwingu, former Apollo flight director Gerry Griffin, former shuttle flight director Wayne Hale and politician Newt Gingrich, who touted the idea of building colonies on the Moon while he was a US presidential candidate.

Golden Spike’s video preview:

During an announcement at the National Press Club today — made on the eve of the 40th anniversary of the launch of Apollo 17, the last human exploration of the Moon — Griffin said that a group of like-minded individuals got together and concluded that time is ripe for such exploration that could be afforded by corporations, nations and individuals. Golden Spike looks to provide turn-key services such as vehicles, mission planning, mission ops, and crew training to create a reliable and affordable lunar exploration system that will be U.S. based

Stern said they will not build new hardware but adapt crew capsules already in development and use existing infrastructure and launchers. However, they are looking to developing their own lunar spacesuits and lunar landers.

Their tentative plan is to use a series of launches where the first launch sends a lunar lander to orbit the Moon and a second launch brings the crew, which will then dock with the lander and head to the Moon.

Stern said their costs per flight are not much higher than some recent robotic lunar missions that have been flown and they will offset their costs with spaceship naming rights, media rights, and other enticements, plus they hope to have several investors as backers.

They also want to bring public along as an integral part of the mission.

“We realize this is science fiction. We intend to make it science fact,” Stern was quoted as saying.

Reportedly, Golden Spike has conferred with NASA on their plans.

While there are already a number of skeptics about this new endeavor, others see it as a step forward.

“Conquering the space frontier requires leadership at NASA and a partnership between commercial companies and governments,” stated Commercial Space Fight President Michael Lopez-Alegria. “I’m thrilled to see the Golden Spike announcement, which harnesses space leaders with years of experience to launch an exciting new private space venture. In the last few years we’ve learned that commercial space, by speaking to the dreams and aspirations of people around the world, can create new excitement for space travel, bringing us ever closer to our shared goal of sustainably extending human activity beyond Earth.”

Other board members include new-space entrepreneur Esther Dyson and Taber McCallum, co-founder and CEO of Paragon Space Development Corporation. The list of advisers for the company former NASA engineer and author Homer Hickam, Bill Richardson, who has served as U.N. ambassador, energy secretary and the governor of New Mexico, space historian and author Andrew Chaikin, former NASA flight surgeon Jonathan Clark, Nancy Conrad who is founder of The Conrad Foundation and is the widow of Apollo 12 moonwalker Pete Conrad.

Golden Spike also lists United Launch Alliance, Armadillo Aerospace, Masten Space Systems and several other space-industry companies as being involved with this new endeavor.

Golden Spike was the name given to the ceremonial spike that joined the rails of the first transcontinental railroad across the United States in 1869, which opened up the Western frontier to new opportunities.

“We’re not just about America going back to the moon; we’re about American industry and American entrepreneurial spirit leading the rest of the world to an exciting era of human lunar exploration,” said Stern in a press release. “It’s the 21st century, we’re here to help countries, companies, and individuals extend their reach in space, and we think we’ll see an enthusiastic customer manifest developing.”

See the Golden Spike website

Sources: Thanks to Jeff Foust (@jeff_foust) for live-Tweeting the press conference and to Doug Messier from Parabolic Arc for live blogging the event.

Posted on by John Williams

Pink Galactic Smackdown Results in Cosmic Bulls-eye

Bright pink nebulae encircle spiral galaxy NGC 922 in this image from the NASA/ESA Hubble Space Telescope. Credit: NASA/ESA. Zoom: John Williams/TerraZoom and Zoomify

Galaxies pack a wallop. A galactic bulls-eye ringed with pink nebulae is the only evidence of a rare galactic collision of NGC 922 that occurred millions of years ago. Clicking the button on the far right of the toolbar will allow awesomecosmicsauce to tantalize your eyes and work all of the pixels on your computer screen. Pressing the “ESC” will return you to the present universe.

Explore this awesome image from the NASA/ESA Hubble Space Telescope. While lovely, something is amiss in this image. NGC 922 used to be a spiral galaxy. As you zoom across the image, the spiral arms look distorted and disrupted. Hints of a galactic interaction are strewn across the galaxy from the large numbers of bright pink nebulae and blue stars to the spray of dim stars toward the top of the image. Ripples set up as the smaller galaxy passed through the gas and dust clouds of NGC 922 created new star formation. Ultraviolet radiation from these bright new stars cause hydrogen gas in the surrounding nebula to glow a characteristic pink. The tugs of gravity hurled thousands of stars outward.

Episode 60 of the Hubblecast explores NGC 922, a galaxy that has been hit square-on by another. Ripples of star-formation are still propagating out across thousands of light-years of space over 300 million years after the collision, making it a prime example of what astronomers call a collisional ring galaxy.

Scientists believe that millions of years ago a small galaxy, known as 2MASXI J0224301-244443, plunged through the heart of NGC 922. Sometimes, if a small galaxy hits a larger galaxy just right, a circle is formed. But more often than not, galaxies are not aligned perfectly. When a galaxy smacks another off center, one side of the ring is brighter than the other. NGC 922 is a prime example of what astronomers call collisional ring galaxies. Although only a few ring galaxies are seen in our cosmic neighborhood, of which the Cartwheel Galaxy is the most spectacular, ring galaxies appear to be commonplace as we peer further into the past.

As you explore the empty places of the image, look for faraway background galaxies. Several dim spiral galaxies dot the image both outside the galaxy and within the star-speckled interior.

NGC 922 is found about 330 million light-years from Earth toward the constellation Fornax. Sky mapper and French astronomer Nicolas Louis de Lacaille introduced Fornax, the Furnace, in 1756. Fornax is relatively devoid of stars allowing astronomers to peer deep into the universe. The constellation was the perfect target for the Hubble Ultra Deep Field image.

NASA/ESA Hubble Space Telescope image of NGC 922. Credit: NASA, ESA

Source: ESA Hubble

Posted on by Jason Major

Titan’s Gravity Indicates a Thicker, Uneven Icy Crust

Color composite of Titan and Dione made from Cassini images acquired in May 2011. (NASA/JPL/SSI/J. Major)

It’s long been speculated that Saturn’s moon Titan may be harboring a global subsurface ocean below an icy crust, based on measurements of its rotation and orbit by NASA’s Cassini spacecraft. Titan exhibits a density and shape that indicates a pliable liquid internal layer — an underground ocean — possibly composed of water mixed with ammonia, a combination that would help explain the consistent amount of methane found in its thick atmosphere.

Now, further analysis of Cassini gravity measurements by a Stanford University team has shown that Titan’s ice layer is thicker and less uniform than originally estimated, indicating a more complex internal structure — and a stronger external influences for its heat.

Titan’s liquid subsurface ocean was previously estimated to be in the neighborhood of 100 km (62 miles) thick, sandwiched between a rocky core below and an icy shell above. This was based on the behavior of Titan in its orbit — or, more precisely, how Titan’s shape changes along the course of its orbit, as measured by Cassini’s radar instrument.

Because Titan’s 16-day orbit is not perfectly circular the moon experiences a stronger gravitational pull from Saturn at certain points than at others. As a result it’s flattened at the poles and constantly changing shape slightly — an effect called tidal flexing. Along with the decay of radioactive materials in its core, this flexing generates the internal heat that helps keep a subsurface ocean liquid.

A team of researchers from Stanford University, led by Howard Zebker, professor of geophysics and electrical engineering, used recent Cassini measurements of Titan’s topography and gravity to determine that the icy layer between the moon’s surface and ocean is up to twice as thick as previously thought — and it’s considerably thicker at the equator than at the poles.

“The picture of Titan that we get has an icy, rocky core with a radius of a little over 2,000 kilometers, an ocean somewhere in the range of 225 to 300 kilometers thick and an ice layer that is 200 kilometers thick,” said Zebker.

Different thicknesses of Titan’s ice layer would mean that there’s less heat being generated internally by the decay of radioactive materials in Titan’s core, because that type of heat would be more or less globally uniform. Instead, tidal flexing caused by the gravitational interactions with Saturn and neighboring smaller moons must play a stronger role in heating Titan’s insides.

Read more: Titan’s Tides Suggest a Subsurface Sea

With Cassini’s new measurements of Titan’s gravity, Zebker and his team calculated that the icy layer below Titan’s flattened poles is 3,000 meters (about 1.8 miles) thinner than average, while at the equator it’s 3,000 meters thicker than average. Combined with the moon’s surface features, this makes the average global thickness of the ice layer to be more like 200 km, not 100.

Heat generated by tidal flexing — which is more strongly felt at the poles — is thought to be the cause of the thinner ice there. Thinner ice would mean there’s more liquid water beneath the poles, which is denser and thus would exert a stronger gravitational pull… exactly what’s been found in Cassini’s measurements.

The findings were announced Tuesday, Dec. 4 at the AGU convention in San Francisco. Read more on the Stanford University news page.

Posted on by Nancy Atkinson

Star Trek Teaser: “Into Darkness” Trailer Released

James T. Kirk and the crew of the Enterprise will be back for a second pre-quel of the young original Enterprise crew with next summer’s “Star Trek Into Darkness.” From this new teaser trailer just released today, it certainly looks dark, with lots of explosions, fight scenes, women screaming, Chris Pine’s Kirk having omnipresent cuts on his face, and what looks like a starship falling into an ocean.

The description of the film on the IMDb website:

After the crew of the Enterprise find an unstoppable force of terror from within their own organization, Captain Kirk leads a manhunt to a war-zone world to capture a one man weapon of mass destruction.

The bad guy (actor Benedict Cumberbatch) has a British accent (wasn’t that big in the 1960’s?) and rumors are starting to surface with Cumberbatch playing either a villain similar to the classic ‘Trek’ nemesis Gary Mitchell, who gains glassy eyes and superpowers and tries to take over the world in the second pilot episode “Where No Man Has Gone Before” for the 60’s TV series, or Khan, the genetically-engineered tyrant who first appeared in the original Trek TV series episode “Space Seed” but was killed in the “Star Trek II: Wrath of Khan” movie. So, in my mind, revisiting Khan would would cause the Trek world to get complicated.

But while the villain hasn’t yet been revealed, it is someone who “has returned,” so expect it to be a familiar name.

From the teaser, it appears all the main actors from the 2009 “Star Trek” film have returned, but does Spock have a new haircut?

A disclaimer: this was posted for all our Trek fans, so don’t complain that this isn’t space or astronomy news, because in our Trekkie minds it is space news.