How Long is a Day on Mercury?

1/3 the distance from the Sun than Earth, it should be no surprise that a day on Mercury is a real scorcher with temperatures soaring over 400 ºC. But in addition to its solar proximity it also has an extremely slow rotation: a single day on Mercury is 58.6 Earth days long… and you thought your Mondays lasted forever!

To be even more precise, for every 2 Mercury years, 3 Mercury days pass — a 3:2 spin-orbit resonance, caused by the planet’s varying elliptical orbit. (This also makes for some interesting motions of the Sun in Mercury’s sky.)

To illustrate this, UK’s The Open University has published a new video in their 60 Second Adventures in Astronomy series… check it out above (and see more of their excellent and amusing animations here.)

Video: The Open University. Narrated by David Mitchell.

In the Shadow of the Moon: Experience a Solar Eclipse From 37 Kilometers Up

The Moon’s shadow stretches over the Earth in this balloon-mounted camera view of the November 14 solar eclipse (Catalin Beldea, Marc Ulieriu, Daniel Toma et. al/Stiinta&Tehnica)

On November 14, 2012, tens of thousands of viewers across northeastern Australia got a great view of one of the most awe-inspiring sights in astronomy — a total solar eclipse. Of course many fantastic photos and videos were taken of the event, but one team of high-tech eclipse hunters from Romania went a step further — or should I say higher — and captured the event from a video camera mounted on a weather balloon soaring over 36,800 meters (120,000 feet) up!

Their video can be seen below:

During a solar eclipse the Moon passes in front of the disk of the Sun, casting its shadow upon the Earth. Any viewers within the darkest part of the shadow — the umbra — will experience a total eclipse, while those within the wider, more diffuse shadow area along the perimeter — the penumbra — will see a partial eclipse.

By launching a weather balloon carrying a wide-angle camera into the stratosphere above Queensland, eclipse hunter and amateur astronomer Catalin Beldea, ROSA research scientist Florin Mingireanu and others on the team were able to obtain their incredible video of the November 14 total eclipse from high enough up that the shadow of the Moon was visible striking Earth’s atmosphere. Totality only lasted a couple of minutes so good timing was essential… but they got the shot. Very impressive!

The mission was organized by teams from the Romanian Space Agency (ROSA) and  Stiinta&, with the video assembled by Daniel Toma and posted on YouTube by editor-in-chief Marc Ulieriu. Music by Shamil Elvenheim.

Unraveling the Secrets of Type Ia Supernovae: a New Two-Minute Thesis

The folks over at PHD Comics have put together a new video in their Two-Minute Thesis series, this one featuring Ph.D candidate Or Graur of the University of Tel Aviv and the American Museum of Natural History discussing the secret lives — and deaths — of astronomers’ “standard candles” of universal distance, Type Ia supernovae.

Judging distances across intergalactic space isn’t easy, so in order to figure out how far away galaxies are astronomers have learned to use the light from Type Ia supernovae, which flare up with the brilliance of 5 billion Suns… and rather precisely so.

Type Ia supernovae are thought to be created from a pairing of two stars: one super-dense white dwarf which draws in material from a binary companion until a critical mass — about 40% more mass than the Sun – is reached. The overpacked white dwarf suddenly undergoes a rapid series of thermonuclear reactions and explodes in an incredibly bright outburst of material and energy.

But exactly what sorts of stellar pairs lead to Type Ia supernovae and how frequently they occur aren’t known, and that’s what Ph.D candidate Or Graur is aiming to learn more about.

Read more: A New Species of Type Ia Supernova?

“We don’t really know what kind of star it is that leads to these explosions, which is kind of embarrassing,” says Graur. “The companion star could be a regular star like our Sun, a red giant or supergiant, or another white dwarf.”

Because stars age at certain rates, by looking deeper into space with the Hubble and Subaru telescopes Graur hopes to determine how often and when in the Universe’s history Type Ia supernovae occur, and thus figure out what types of stars are most likely responsible.

“My rate measurements favor a second white dwarf as the binary companion,” Graur says, “but the issue is far from settled.”

Watch the video for the full story, and visit PHD TV and PHD Comics for more great science illustrations.

Video: PHDComics. Animation: Jorge Cham. Series Producer: Meg Rosenburg. Inset image: merging white dwarfs causing a Type Ia supernova. (NASA/CXC/M Weiss)

Our Gorgeous, Graceful, Gradient Sun

Here’s a mesmerizing video from the folks over at NASA’s Goddard Space Flight Center’s visualization studio showing the Sun in a whole new light… well, a reprocessed light anyway.

Using what’s called a gradient filter, images of the Sun can be adjusted to highlight the intricate details of its dynamic atmosphere. Magnetic activity that’s invisible to human vision can be brought into view, showing the powerful forces in play within the Sun’s corona and helping researchers better understand how it affects space weather. (Plus they sure are pretty!)

Compiled into a video, these images reveal the hidden beauty — and power — of our home star in action.

Video courtesy NASA/GSFC

Watch: Incredible Headcam Video from Felix’s Freefall

Felix Baumgartner salutes his suit-mounted camera before stepping off his capsule’s platform at 128,000 feet (Red Bull Stratos)

Yesterday, October 14, Austrian pilot and BASE jumper Felix Baumgartner became the first person to skydive from over 128,000 feet, breaking the sound barrier during his 4 minute, 20 second plummet from the “edge of space.” A new video from Red Bull Stratos includes views from Felix’s suit-mounted cameras as he drops through virtually no atmosphere, smoothly at first but then going into a wild spin… but eventually stabilizing himself for the remainder of his fall and opening his chute at just over 6,000 feet. Incredible!

Check out the video below:

Here’s how Baumgartner described the spin and how he got out of it during the press conference after his jump yesterday:

“It started out really good because my exit was perfect, I did exactly what I was supposed to do… It looked like for a second I was going to tumble two more times and then get it under control, but for some reason that spin became so violent over all axis and it was hard to know how to get out of it, because, if you are trapped in a pressurized suit – normally as a skydiver you can feel the air and get direct feedback from the air — but here you are trapped in a suit that is pressurized at 3.5 PSI so you don’t know how to feel the air. It is like swimming without touching the water. And it’s hard because every when time it turns you around you have to figure out what to do. So I was sticking my arm out and it became worse and then I stuck arm out the other side and it became less, so I was fighting all the way down to regain control because I wanted to break the speed of sound. And I hit it. I don’t know how many seconds, but I could feel air was building up and then I hit it.”

So, in that quote, Baumgartner seemed to describe that he could feel when he broke the speed of sound, but in answering the next question of how it felt, he kind of backtracked and said he didn’t feel it.

“It’s hard to describe because I didn’t feel it. When you are in the pressure suit, you don’t feel anything, it is like being in a cast…. We have to look at the data – at what point did it happen — was I still spinning or was I under control? If you want to chart speed you need a reference point of things that pass you by, or sound, or your suit if flapping. I didn’t have that.”

Read more about Baumgartner’s record (and sound!) -breaking achievement and see lots more images and video here.

ADDED: A version of the video showing his chute opening (and with some background music added) can be found here on

What Happens When Supermassive Black Holes Merge?

Frame from a simulation of the merger of two black holes and the resulting emission of gravitational radiation (NASA/C. Henze)

The short answer? You get one super-SUPERmassive black hole. The longer answer?

Well, watch the video below for an idea.

This animation, created with supercomputers at the University of Colorado, Boulder, show for the first time what happens to the magnetized gas clouds that surround supermassive black holes when two of them collide.

The simulation shows the magnetic fields intensifying as they contort and twist turbulently, at one point forming a towering vortex that extends high above the center of the accretion disk.

This funnel-like structure may be partly responsible for the jets that are sometimes seen erupting from actively feeding supermassive black holes.

The simulation was created to study what sort of “flash” might be made by the merging of such incredibly massive objects, so that astronomers hunting for evidence of gravitational waves — a phenomenon first proposed by Einstein in 1916 — will be able to better identify their potential source.

Read: Effects of Einstein’s Elusive Gravity Waves Observed

Gravitational waves are often described as “ripples” in the fabric of space-time, infinitesimal perturbations created by supermassive, rapidly rotating objects like orbiting black holes. Detecting them directly has proven to be a challenge but researchers expect that the technology will be available within several years’ time, and knowing how to spot colliding black holes will be the first step in identifying any gravitational waves that result from the impact.

In fact, it’s the gravitational waves that rob energy from the black holes’ orbits, causing them to spiral into each other in the first place.

“The black holes orbit each other and lose orbital energy by emitting strong gravitational waves, and this causes their orbits to shrink. The black holes spiral toward each other and eventually merge,” said astrophysicist John Baker, a research team member from NASA’s Goddard Space Flight Center. “We need gravitational waves to confirm that a black hole merger has occurred, but if we can understand the electromagnetic signatures from mergers well enough, perhaps we can search for candidate events even before we have a space-based gravitational wave observatory.”

The video below shows the expanding gravitational wave structure that would be expected to result from such a merger:

If ground-based telescopes can pinpoint the radio and x-ray flash created by the mergers, future space telescopes — like ESA’s eLISA/NGO — can then be used to try and detect the waves.

Read more on the NASA Goddard new release here.

First animation credit: NASA’s Goddard Space Flight Center/P. Cowperthwaite, Univ. of Maryland. Second animation: NASA/C. Henze.


A River Ran Through It: Why Do They Think There Was Once Water on Mars?

Why is everyone so excited about these dusty Mars rocks?

This week’s big news was the announcement of evidence for flowing water on Mars, based on images of what appear to be smooth river rock-type pebbles found by Curiosity. Of course that’s a big statement to make, and for good reason — identifying water, whether present or past, is one step closer to determining whether Mars was ever a suitable place for life to develop. Yet here we are, not even two months into the mission and Curiosity is already sending us solid clues that Mars was once a much wetter place than it is now.

JPL released a video today providing a brief-but-informative overview of what Curiosity has discovered in Gale Crater and why it’s gotten everyone so excited.

Check it out so you’ll have something to talk about over the weekend:

MSL Long Term Planner Sanjeev Gupta reviews Curiosity’s latest discovery

Video: JPLNews. Images: NASA/JPL-Caltech

How Many Asteroids Are Out There?

Answer: a LOT. And there’s new ones being discovered all the time, as this fascinating animation by Scott Manley shows.

Created using data from the IAU’s Minor Planet Center and Lowell Observatory, Scott’s animation shows the progression of new asteroid discoveries since 1980. The years are noted in the lower left corner.

As the inner planets circle the Sun, asteroids light up as they’re identified like clusters of fireflies on a late summer evening. The clusters are mainly positioned along the outer edge of Earth’s orbit, as this is the field of view of most of our telescopes.

Once NASA’s WISE spacecraft begins its search around 2010 the field of view expands dramatically, as well as does the rate of new discoveries. This is because WISE’s infrared capabilities allowed it to spot asteroids that are composed of very dark material and thus reflect little sunlight, yet still emit a telltale heat signature.

While Scott’s animation gives an impressive — and somewhat disquieting — illustration of how many asteroids there are knocking about the inner Solar System, he does remind us that the scale here has been very much compacted; a single pixel at the highest resolution corresponds to over 500,000 square kilometers! So yes, over half a million asteroids is a lot, but there’s also a lot of space out there (and this is just a 2D top-down view too… it doesn’t portray any vertical depth.)

While most asteroids are aligned with the horizontal plane of the Solar System, there are a good amount whose orbits take them at higher inclinations. And on a few occasions they even cross Earth’s orbit.

(Actually, on more than just a few.)

Read: 4700 Asteroids Want to Kill You

An edge-on view of the Solar System shows the positions of asteroids identified by the NEOWISE survey. About 4700 potentially-hazardous asteroids (PHAs) have been estimated larger than 100 meters in size. (NASA/JPL-Caltech)

As far as how many asteroids there are… well, if you only consider those larger than 100 meters orbiting within the inner Solar System, there’s over 150 million. Count smaller ones and you get even more.

I don’t know about you but even with the distances involved it’s starting to feel a little… crowded.

You can see more of Scott Manley’s videos on YouTube here (including some interesting concepts on FTL travel) and learn more about asteroids and various missions to study them here.

Inset image: the 56-km (35-mile) wide asteroid Ida and its satellite, seen by the Galileo spacecraft in 1993. (NASA)

Fly Over California Alongside a Space Shuttle!

A view of Endeavour and SCA over California from one of NASA’s F/A-18 chase planes (NASA/DFRC)

We’ve shared several videos from Endeavour’s trip to Los Angeles last week, taken by excited spectators along various portions of the flight path, but what was it like for the crews of the two NASA F/A-18 chase planes that accompanied the orbiter and SCA every step of the way?

Watch the video below, and put yourself in the pilot’s seat…

Shared by NASA’s Dryden Flight Research Center, the video shows footage taken from the viewpoint of one of the chase planes as Endeavour was ferried aboard a Shuttle Carrier Aircraft from Edwards Air Force Base to Los Angeles International Airport.

Along the way SCA pilots Jeff Moultrie and Bill Rieke, both from NASA’s Johnson Space Center, guided the 747 over such landmarks as the State Capitol in Sacramento, the Golden Gate Bridge at San Francisco, and NASA’s Ames Research Center.

Once over the Los Angeles area Endeavour passed over well-known landmarks like Griffith Observatory, the Hollywood sign, Dodger Stadium, NASA’s Jet Propulsion Laboratory, Malibu Beach and the Santa Monica Pier, and Disneyland.

After several low flybys of the runway — some under 300 feet! — the SCA touched down at LAX on Runway 25L at 12:51 p.m. PDT.

NASA’s four F/A-18 Hornet aircraft, operated by Dryden Flight Research Center, are commonly called chase planes and fill the role of escort aircraft during research missions. They also are used as camera platforms for research missions that must be photographed or videotaped. Two of these chase planes accompanied Endeavour on its flight for such documentation as well as for security.

See more images of the F/A-18s here, and for more photos of Endeavour’s trip to California check out the NASA photographer photo set on Flickr.

Video: Dryden TV

Watch Jupiter Get Hit in the Original HD Video

Caught on webcam by amateur astronomer George Hall in Dallas, Texas, the impact on Jupiter that occurred yesterday at 6:35 a.m. CT can be clearly seen in the brief video above as a bright flash along the giant planet’s left side.

According to Hall on his website the video was captured with a 12″ LX200GPS, 3x Televue Barlow, and Point Grey Flea 3 camera using Astro IIDC software.

Great catch, George! Currently this is the only video footage we’ve seen of this particular event. Also, tonight at 10 p.m. ET / 7 p.m. PT the SLOOH Space Camera site will broadcast a live viewing of Jupiter to search for any remaining evidence of an impact. Tune in here.

Video © George Hall. All rights reserved, used with permission.