Raw data showing the raw gamma ray light curve from a possible Gamma Ray Burst in M31 on May 27, 2014 obtained by the Swift Burst Alert Telescope. Credit: Goddard Space Flight Center/NASA
Something went boom in the Andromeda Galaxy, our next door neighbor. The Swift Gamma-Ray Burst telescope detected a sudden bright emission of gamma rays. Astronomers aren’t sure yet if it was a Gamma-Ray Burst (GRB) or an Ultraluminous X-Ray (ULX) or even an outburst from a low-mass x-ray binary (LMXB), but whatever it turns out to be, it will be the closest event of this kind that we’ve ever observed.
One of the previous closest GRBs was 2.6 billion light-years away, while Andromeda is a mere 2.5 million light years away from Earth. Even though this would be the closest burst to Earth, there is no danger of our planet getting fried by gamma rays.
According to astronomer (Bad Astronomer!) Phil Plait, a GRB would have to be less than 8,000 light years away cause any problems for us.
Andromeda Galaxy. Credit: NASA
This event is providing astronomers with a rare opportunity to gain information vital to understanding powerful cosmic explosions like this.
If it is a GRB, it likely came from a collision of neutron stars. If it is a ULX, the blast came from a black hole consuming gas. If the outburst was from a LMXB, a black hole or neutron star annihilated its companion star.
Astronomers should be able to determine the pedigree of this blast within 24-48 hours by watching the way the light fades from the burst.
How this Blast was Detected
The Swift Burst Alert telescope watches the sky for gamma-ray bursts and, within seconds of detecting a burst Swift relays the location of the burst to ground stations, allowing both ground-based and space-based telescopes around the world the opportunity to observe the burst’s afterglow. As soon as it can, Swift will swiftly shift itself to observe the burst with its X-ray and ultraviolet telescopes.
The burst alert came at 21:21 pm Universal time on May 27, 2014; three minutes later, the X-ray telescope aboard Swift was observing a bright X-ray glow.
News of the event quickly spread across the astronomical community and on Twitter, sending astronomers scrambling for their telescopes.
Remember scene in Contact where they got a weird signal & called up astronomers all over the world to look? That happens for GRBs. #GRBm31
According to astronomer Katie Mack on Twitter, if this is indeed a GRB, this gamma-ray burst looks like a short GRB.
No two GRBs are the same, but they are usually classified as either long or short depending on the burst’s duration. Long bursts are more common and last for between 2 seconds and several minutes; short bursts last less than 2 seconds, meaning the action can all be over in just milliseconds.
As we noted earlier, more should be known about this blast within a day or so and we’ll keep you posted. In the meantime, you can follow the hashtag #GRBM31 on Twitter to see the latest. Katie Mack or Robert Rutledge (Astronomer’s Telegram) have been tweeting pertinent info about the burst.
SpaceX Dragon cargo freighter berthed to the International Space Station during recently concluded SpaceX-3 mission in May 2014. An upgraded, manrated version will carry US astronauts to space in the next two to three years. Credit: NASA
SpaceX Dragon cargo freighter berthed to the International Space Station during recently concluded SpaceX-3 mission in May 2014. An upgraded, manrated version will carry US astronauts to space in the next two to three years. Credit: NASA Story updated[/caption]
SpaceX CEO, founder and chief designer Elon Musk is set to unveil the manned version of his firms commercial Dragon spaceship later this week, setting in motion an effort that he hopes will soon restore America’s capability to launch US astronauts to low Earth orbit and the International Space Station (ISS) by 2017.
Musk will personally introduce SpaceX’s ‘Space Taxi’ dubbed ‘Dragon V2’ at what amounts to sort of a world premiere event on May 29 at the company’s headquarters in Hawthorne, CA, according to an official announcement this evening (May 27) from SpaceX.
“SpaceX’s new Dragon V2 spacecraft is a next generation spacecraft designed to carry astronauts into space,” according to the SpaceX statement.
The manned Dragon will launch atop the powerful SpaceX Falcon 9 v1.1 rocket from a SpaceX pad on the Florida Space Coast.
Dragon was initially developed as a commercial unmanned resupply freighter to deliver 20,000 kg (44,000 pounds) of supplies and science experiments to the ISS under a $1.6 Billion Commercial Resupply Services (CRS) contract with NASA during a dozen Dragon cargo spacecraft flights through 2016.
Musk is making good on a recent comment he posted to twitter on April 29, with respect to the continuing fallout from the deadly crisis in Ukraine which has resulted in some US economic sanctions imposed against Russia, that now potentially threaten US access to the ISS in a boomerang action from the Russian government:
“Sounds like this might be a good time to unveil the new Dragon Mk 2 spaceship that @SpaceX has been working on with @NASA. No trampoline needed,” Musk tweeted.
“Cover drops on May 29. Actual flight design hardware of crew Dragon, not a mockup,” Musk added.
The ‘Dragon V2’ is an upgraded, man rated version of the unmanned spaceship that can carry a mix of cargo and up to a seven crewmembers to the ISS.
NASA astronauts and industry experts check out the crew accommodations in the Dragon spacecraft under development by SpaceX. The evaluation in Hawthorne, Calif., on Jan. 30, 2012, was part of SpaceX’s Commercial Crew Development Round 2 agreement with NASA’s Commercial Crew Program. Credit: NASA
Dragon is among a trio of US private sector manned spaceships being developed with seed money from NASA’s Commercial Crew Program in a public/private partnership to develop a next-generation crew transportation vehicle to ferry astronauts to and from the ISS by 2017 – a capability totally lost following the space shuttle’s forced retirement in 2011.
Since that day, US astronauts have been totally dependent on the Russian Soyuz capsules for ferry rides to orbit and back.
The BoeingCST-100 and Sierra Nevada Dream Chaser ‘space taxis’ are also vying for funding in the next round of contracts to be awarded by NASA around late summer 2014.
All three company’s have been making excellent progress in meeting their NASA mandated milestones in the current contract period known as Commercial Crew Integrated Capability initiative (CCiCAP) under the auspices of NASA’s Commercial Crew Program.
However, US progress getting the space taxis actually built and flying has been repeatedly stifled by the US Congress who have severely cut NASA’s budget request for the Commercial Crew Program by about half each year. Thus forcing NASA to delay the first manned orbital test flights by at least 18 months from 2015 to 2017.
The situation with regard to US dependency on Russian rocketry to reach the ISS has always been awkward.
But it finally took on new found importance and urgency from politicos in Washington, DC, since the ongoing crisis in Ukraine this year exposed US vulnerability in a wide range of space endeavors affecting not just astronaut rides to the ISS but also the launch of the most critical US national security surveillance satellites essential to US defense.
US space vulnerability became obvious to everyone when Russia’s deputy prime minister, Dmitry Rogozin. who is in charge of space and defense industries, said that US sanctions could “boomerang” against the US space program and that perhaps NASA should “deliver their astronauts to the International Space Station using a trampoline.”
A SpaceX Falcon 9 rocket with Dragon cargo capsule bound for the ISS launched from Space Launch Complex 40 at Cape Canaveral, FL. File photo. Credit: Ken Kremer/kenkremer.com
Rogozin also threatened to cut off exports of the Russian made RD-180 rocket engines which power the first stage of the United Launch Alliance (ULA) Atlas V rocket used to launch numerous US National Security spy satellites.
“Moscow is banning Washington from using Russian-made rocket engines, which the US has used to deliver its military satellites into orbit,” Rogozin said at a media briefing held on May 13.
NASA is also a hefty user of the Atlas V for many of the agency’s science and communication satellites like the Curiosity Mars rover, MAVEN Mars orbiter, MMS, Juno Jupiter orbiter and TDRS.
Musk and SpaceX have also filed lawsuits against the US Air Force to legally block the importation of the RD-180 engines by ULA for the Atlas V as a violation of the US economic sanctions.
So overall, US space policy is in a murky and uncertain situation and Musk clearly aims for SpaceX to be a central and significant player in a wide range of US space activities, both manned and unmanned.
Read my earlier articles about the Atlas V controversy, Rogozin’s statements, Musk’s suit and more about the effects of economic sanctions imposed by the US and Western nations in response to Russia’s actions in Ukraine and the annexation of Crimea; here, here, here, here and here.
SpaceX founder and CEO Elon Musk briefs reporters including Universe Today in Cocoa Beach, FL prior to SpaceX Falcon 9 rocket blastoff with SES-8 communications satellite on Dec 3, 2013 from Cape Canaveral, FL. Credit: Ken Kremer/kenkremer.com
The 3rd operational Dragon cargo resupply mission completed the 30 day SpaceX-3 flight to the ISS with a successful Pacific Ocean splashdown on May 18.
SpaceX will webcast the Dragon unveiling event LIVE on May 29 at 7 p.m. PST for anyone wishing to watch at: www.spacex.com/webcast
Stay tuned here for Ken’s continuing SpaceX, Boeing, Sierra Nevada, Orbital Sciences, commercial space, Orion, Mars rover, MAVEN, MOM and more planetary and human spaceflight news.
SpaceX Falcon 9 rocket successfully launched the SES-8 communications satellite on Dec. 3, 2013 from Pad 40 at Cape Canaveral, FL. Credit: Ken Kremer/kenkremer.com
A Camelopardalids meteor captured
at Jebel Al Jais mountain on the morning of May 24, 2014. Credit and copyright: Justin Ng.
The first ever Camelopardalids Meteor Shower ended up being more of a drizzle than a shower, said astrophotographer John Chumack. “The new shower had very few meteors per hour, I estimated about 8 to 12 per hour, most were faint, but it did produce a few bright ones, as seen captured by my Meteor Video Camera network at my backyard observatory in Dayton Ohio.”
The above image is by Justin Ng who went to Jebel Al Jais mountain near Dubai to capture the meteor shower.
As our own Bob King reported the morning after — with several images and apt descriptions of the shower — the peak activity seem to occur around 2:00am to 4:00am EST (0700 to 900 UT).
There was a lot of buzz about a weird gigantic persistent train that occurred early on (about 1 am EST) and it ended up being a cameo appearance by the Advanced Land Observation Satellite a new Japanese mapping satellite, and a fuel dump from a booster stage of the satellite’s launch vehicle. Read more about it at Bob’s article, and see some images of it below.
Also, see a great video capture of a persistent train, shot by astrophotographer Gavin Heffernan:
We’ve had some more images come in via email and on our Flickr page
Persistent trains are the vaporized remains of the tiny meteoroid. The dust is blown around by upper level winds in Earth’s atmosphere.
Here’s a great time-lapse of the plume from the fuel dump. Astrophotographer Alan Dyer called it a “strange glow of light that moved across the northern sky… What I thought was an odd curtain of slow-moving, colourless aurora — and I’ve seen those before — has many people who also saw it suspecting it was a glow from a fuel dump from an orbiting satellite.
This short time-lapse of 22 frames covers about 22 minutes starting at 11:59 pm MDT on May 23 Each frame is a 60-second exposure taken at 2 second intervals, played back at one frame per second.
A Camelopardolids Meteor on May 24, 2014. Credit and copyright: Stephen Rahn.Camelopardalids Meteor zips past the Big Dipper and Mars on May 24, 2014. Credit and copyright: John Chumack.
Here’s a video compilation put together by John Chumack:
Closeup of one frame of a timelapse session containing what appears to be a meteor from the Camelopardalids meteor shower. Credit and copyright: DaretheHair on Flickr.An animated gif of the strange ‘cloud’ plume from a fuel dump from the launch of a new Japanese mapping satellite. Credit and copyright: DaretheHair.
We’ll add more images as they come in!
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 dazzling full moon sets behind the Very Large Telescope in Chile’s Atacama Desert in this photo released June 7, 2010 by the European Southern Observatory. The moon appears larger than normal due to an optical illusion of perspective.
Image Credit: Gordon Gillet, ESO.
Astronomy is a discipline pursued at a distance. And yet, actually measuring that last word — distance — can be incredibly tricky, even if we set our sights as nearby as the Moon.
But now astronomers from the University of Antioquia, Colombia, have devised a clever method that allows citizen scientists to measure the Moon’s distance with only their digital camera and smartphone.
“Today a plethora of advanced and accessible technological devices such as smartphones, tablets, digital cameras and precise clocks, is opening a new door to the realm of ‘do-it-yourself-science’ and from there to the possibility of measuring the local Universe by oneself,” writes lead author Jorge Zuluaga in his recently submitted paper.
While ancient astronomers devised clever methods to measure the local Universe, it took nearly two millennia before we finally perfected the distance to the Moon. Now, we can bounce powerful lasers off the mirrors placed on the Lunar surface by the Apollo Astronauts. The amount of time it takes for the laser beam to return to Earth gives an incredibly precise measurement of the Moon’s distance, within a few centimeters.
But this modern technique is “far from the realm and technological capacities of amateur astronomers and nonscientist citizens,” writes Zuluaga. In order to bring the local Universe into the hands of citizen scientists, Zuluaga and colleagues have devised an easy method to measure the distance to the Moon.
The trick is in observing how the apparent size of the Moon changes with time.
As the moon rises its distance to an observer on the surface of the Earth is slightly reduced. Image Credit: Zuluaga et al.
While the Moon might seem larger, and therefore closer, when it’s on the horizon than when it’s in the sky — it’s actually the opposite. The distance from the Moon to any observer on Earth decreases as the Moon rises in the sky. It’s more distant when it’s on the horizon than when it’s at the Zenith. Note: the Moon’s distance to the center of the Earth remains approximately constant throughout the night.
The direct consequence of this is that the angular size of the moon is larger — by as much as 1.7 percent — when it’s at the Zenith than when it’s on the horizon. While this change is far too small for our eyes to detect, most modern personal cameras have now reached the resolution capable of capturing the difference.
So with a good camera, a smart phone and a little trig you can measure the distance to the Moon yourself. Here’s how:
1.) Step outside on a clear night when there’s a full Moon. Set your camera up on a tripod, pointing at the Moon.
2.) With every image of the Moon you’ll need to know the Moon’s approximate elevation. Most smartphones have various apps that allow you to measure the camera’s angle based on the tilt of the phone. By aligning the phone with the camera you can measure the elevation of the Moon accurately.
3.) For every image you’ll need to measure the apparent diameter of the Moon in pixels, seeing an increase as the Moon rises higher in the sky.
4.) Lastly, the Moon’s distance can be measured from only two images (of course the more images the better you beat down any error) using this relatively simple equation:
where d(t) is the distance from the Moon to your location on Earth, RE is the radius of the Earth, ht(t) is the elevation of the Moon for your second image, α(t)
is the relative apparent size of the Moon, or the apparent size of the Moon in your second image divided by the initial apparent size of the Moon in your first image and ht,0 is the initial elevation of the Moon for your first image.
So with a few pictures and a little math, you can measure the distance to the Moon.
“Our aim here is not to provide an improved measurement of a well-known astronomical quantity, but rather to demonstrate how the public could be engaged in scientific endeavors and how using simple instrumentation and readily available technological devices such as smartphones and digital cameras, any person can measure the local Universe as ancient astronomers did,” writes Zuluaga.
The paper has been submitted to the American Journal of Physics and is available for download here.
Time exposure showing the International Space Station making a bright pass across the northern sky. Credit: Bob King
What’s your favorite satellite? For me it’s the space station. Not only is it the brightest spacecraft in the sky, but it’s regularly visible from so many places. It’s also unique. Most satellites are either spent rocket stages or unmanned science and surveillance probes. The ISS is inhabited by a crew of astronauts. Real people.
Every time I see that bright, moving light I think of the crew floating about the cabin with their microgravity hair, performing experiments and pondering the meaning of it all while gazing out the cupola windows at the rolling blue Earth below. Starting Friday, the station will make up to 5 flybys a night from dusk till dawn. Marathon anyone?
The ISS’s orbit is inclined 51.6 degrees to the equator and passes overhead for anyone living between 51.6 degrees north and 51.6 degrees south latitude. It’s visible well beyond this zone also but never passes through the zenith outside of these limits. Traveling at a little more than 17,000 mph (27,350 kph) the station completes an orbit in 93 minutes.
Diagram showing the Earth in late May when the space station’s orbital track is closely aligned with the day-night terminator. The astronauts see the sun 24-hours a day (midnight sun effect) while we on the ground get to watch repeated passes. Credit: Bob King
Most of the time we get one easy-to-see bright pass preceded or followed by a fainter partial pass. ‘Partials’ occur when the space station glides into Earth’s shadow and disappears from view during an appearance. But in late May-early June each year, the space station’s orbit and Earth’s day-night terminator nearly align. From the astronauts’ viewpoint, the sun never sets, much like seeing the midnight sun from the Arctic Circle. From down on the planet between latitudes 40-55 degrees north, the ISS remains in sunlight during repeated 90 minute-long orbits.
Instead of once or twice a night, we’ll see passes all night long from dusk till dawn starting about May 30. For instance, on May 31 from Minneapolis, Minn., skywatchers will be treated to four flybys at 12:12 a.m, 1:44 a.m., 3:20 a.m. and 11:23 p.m. The best nights are June 4 and 6 with five passes. By the 10th, the space station ‘marathon’ winds down and we return to 2-3 passes a night.
In late May-early June near the summer solstice, the sun doesn’t set on the International Space Station
The ISS always appears in the western sky first and travels east opposite to the movement of the stars. Low altitude flybys are fainter because there’s more lateral distance between you and the station. Even then the it still shines as bright as Vega. But when the ISS flies overhead, it’s only about 250 miles away, as close as it gets. Then it outshines everything in the night sky except Venus and the moon. Absolutely stunning.
The track of the ISS near Vega in Lyra. From right to left, the station is passing from sunlight into Earth’s shadow. Its color transitions from white to red. Credit: Bob King
Have you ever noticed that satellites, including the ISS, appear to move in a jerky or zigzag fashion if you watch them closely? What you’re really are your own eyes not moving smoothly as you follow the satellite across the starry sky. My favorite passes are those where the space station fades away mid-flyby as it encounters Earth’s shadow. I always keep binoculars handy for these passes so I can watch the ISS turn color from pale yellow (caused by the gold Mylar plastic used in its many solar panels) to orange and red as it experiences one of its many orbital sunsets.
The phenomenon is easy to capture on camera too. Find out when the station will cross into shadow using the maps from Heavens-Above (see below) and point your tripod-mounted camera in that direction. I typically use a 35mm lens wide open to f/2.8 and a 30-second exposure at either ISO 400 – if still twilight – or 800 in a darker sky.
The multiple solar panels on the ISS give it the shape of the letter ‘H’ when viewed through a telescope. Other modules are visible too but hard to see as clearly. Credit: NASA
There are many ways to find out when the ISS will pass over your city. My favorite are the listings in Heavens-Above. Login with your city and you’ll see a complete list with links to create maps of the station’s track across the sky. There’s also Spaceweather’s Satellite Flyby tracker. Type in your zip code and hit enter. Couldn’t be easier. You can also have NASA send you an e-mail when the most favorable (highest, brightest) passes occur by adding your e-mail to the Spot the Station site. Be aware though that you won’t be notified of some of the less favorable passes.
Half-minute video of the space station tracked through a telescope
One last pleasure of space station watching is seeing it in a telescope. Notoriously tricky to track when magnified, after minimal research I’ve come up with a method that allows at least a half dozen people to see it up close during a good flyby. One person mans the finderscope, keeping the station in the center of the crosshairs, while one happy observer after another takes their turn for a look through the eyepiece. Sure, it’s a little herky-jerky, but you’d be surprised how much you can see at magnifications as low as 60x. The solar panels really jump out. Observing solo might mean a couple tries positioning the moving target ahead of where you think it will cross the field of view and then being ready to lock on and follow.
Well, I’m going to prep for the upcoming marathon. See you in spirit on the course!
Dextre, the Canadian Space Agency's robotic handyman aboard the International Space Station. Credit: CSA/NASA
In a thrilling demonstration of space robotics, today the Dextre “hand” replaced a malfunctioning camera on the station’s Canadarm2 robotic arm. And the Canadian Space Agency gleefully tweeted every step of the way, throwing in jokes to describe what was happening above our heads on the International Space Station.
“Dextre’s job is to reduce the risk to astronauts by relieving them of routine chores, freeing their time for science,” the Canadian Space Agency tweeted today (May 27) .
“Spacewalks are thrilling, inspiring, but can potentially be dangerous. They also take a lot of resources and time. So Dextre is riding the end of Canadarm2 today instead of an astronaut. And our inner child is still yelling out ‘Weeeee…!’ ”
The complex maneuvers actually took a few days to accomplish, as the robot removed the broken camera last week and stowed it. Today’s work (performed by ground controllers) was focused on putting in the new camera and starting to test it. You can see some of the most memorable tweets of the day below.
The cookie you see in the first tweet is part of a tradition in Canada’s robotic mission control near Montreal, Que., where controllers have this snack on the day when they are doing robotic work in space.
No rocket sleds were harmed in the making of this video. (NASA/JPL)
So what does an agency like NASA do after making a daring new type of landing with the Mars Curiosity rover? Try to make it even better for next time.
NASA is readying a new technology for landing on the Red Planet that is supposed to help brake the spacecraft in the atmosphere by inflating a buffer around the heat shield to slow things down. And after testing this so-called “Low-Density Supersonic Decelerator” on a rocket sled in January and April, the team is ready for the next major test: heading aloft.
As early as June 3, NASA will strap a test device below a high-altitude balloon and send it up to 120,000 feet — about the same altitude that Felix Baumgartner jumped from in 2012. The device will then drop from the balloon sideways, spinning like a football, and reach a velocity of four times the speed of sound. Then the LDSD will inflate, if all goes as planned, and NASA will evaluate how well it performs.
The agency hopes to use this technology to land heavier and heavier spacecraft on the Red Planet. If the testing goes as scheduled and the funding is available, NASA plans to use an LDSD on a spacecraft as early as 2018.
Neptune's largest Moon, Triton. Astronomers think that Triton is a captured Kuiper Belt Object. Credit: NASA/JPL
Leaving aside the complications of space treaties, a new video lays out another case for why you wouldn’t want to purchase property on Triton — at least, if you were buying for the ultra-long term, over millions of years. The moon is being slowed down by Neptune and will eventually crash or break up into a ring system.
All joking aside, the video also puts forward an interesting hypothesis: that Triton was once a dwarf planet, with a companion, and that Neptune captured Triton and flung the companion away when the giant gas planet moved further out into the solar system, billions of years ago.
Checking into the theory’s credentials, it’s worth noting that the author — Kurzgesagt — represents a startup company that has posted other videos about the solar system. They’re cutely done, although the company’s website does not appear to list any names, at least yet; they describe themselves as a “team of designers, journalists and musicians.” (That might be because they’re operating in “stealth mode”, a term describing startups that aren’t quite ready to make their idea or founders public yet.)
NASA’s web page about Triton doesn’t mention the binary system or dwarf planet hypothesis, but says “scientists think Triton is a Kuiper Belt Object captured by Neptune’s gravity millions of years ago.” (The Kuiper Belt is a collection of objects near Neptune’s orbit.)
Some of the reasons include its strange orbital motion that is opposite to Neptune’ s rotation, and the fact that Triton is overwhelmingly the largest moon in the system — suggesting it ejected other ones when it was captured.
Makes you want to send another spacecraft to Neptune, doesn’t it? The first and only visitor there, Voyager 2, flew past there in 1989.
Expedition 40 NASA astronaut Reid Wiseman participates in a spacesuit fit-check prior to his scheduled flight to space in May 2014. Credit: NASA
Small populations make it really hard to do scientific studies, because the sample size may not be representative of the population being studied. And that’s the challenge with spaceflight, right before you start: only so many people head up there and take part of your experiments. With less than 20 people heading to space per year these days, that’s a tiny population to do medical studies from.
“One of the advantages that terrestrial medicine has is a lot of people to study,” said Jean Sibonga, the bone lead of NASA’s human spaceflight program. “While we’re acquiring our data using the conventional clinical methods for testing bone health here on Earth, terrestrial medicine is running these same studies and getting the results sooner.”
But for a small group being studied, the science is highly professionalized. NASA’s scientists are part of many professional societies ranging from anesthesia to bone science to nutrition. They collaborate with people all over the world. And slowly, as the results come in, they say they are making progress in understanding how space deconditions our bodies and how to make them stronger again.
With bone — where for decades, physicians have tried to figure out which populations are most at risk for fractures — comes an example of another hurdle. The astronauts are young, usually 50 or below, making them statistically one of the least at risk for fractures until they expose themselves to microgravity. This means that comparing them to seniors is “clearly not an appropriate test for our population,” Sibonga said.
One challenge of spaceflight is comparing data from astronauts, in the prime of their career, to seniors. Both groups can have similar health issues, but for different reasons: astronauts are exposed to microgravity, while seniors have aged. Pictured are Expedition 40’s Maxim Surayev (age 41) and Reid Wiseman (age 38). Credit: NASA/Victor Zelentsov
But for what it’s worth, NASA has adapted international clinical guidelines to identify astronauts who have optimal bone health, and to see if the “countermeasures” — weight-bearing exercises — are having any success. This also means looking at the astronaut’s entire picture of health, from family history to medication intake to hormone levels, to see if these variables have any sorts of effect. (More on the results of these tests tomorrow.)
The issue with astronauts, Sibonga said, is they go through very rapid bone losses — even faster than what postmenopausal women experience. Astronauts lose about 1% of their bone density on average per month from their hip and spine. In aging women, vertebrae are the most affected and they can find themselves with “compression fractures” where the vertebrae collapse and their backs are stooped over.
Astronauts may be at risk, but it’s hard with tests on the space station to see if this is happening real time. This work has to wait until they get back to Earth. Sibonga said NASA is trying to fix that. “We’re doing market surveys, and if we find a promising technology for inflight monitoring, we will work to develop and validate these tests in these astronauts.”
Regular exercise is one way that astronauts prepare for the rigors of orbit. Here, Expedition 32 JAXA astronaut Akihiko Hoshide does maintenance on the International Space Station during a spacewalk in 2012. Credit: NASA
Sometimes that technology comes from other sectors. The idea of “loading” not only applies to human health, but also to engineering. So some of the same models could have relevancy between engineering and humans. One device NASA has been testing on the ground is a quantitative computed tomography (QCT), an imager that quantifies the amount of bone mass an astronaut has in true three dimensions. From these QCT data, engineers can develop models to estimate the mechanical loads that would cause a bone to fracture. But only a handful of people have applied this engineering model to biological systems, Sibonga said.
Naturally, NASA is also interested in how much bone mineral density (BMD) comes back after a mission. BMD tests are done every three years in astronauts from the time they are selected (bearing in mind the technology was not available until about the mid-1990s). Uniquely, NASA also invites its astronauts back after they leave or retire to continue the tests — a practice even the military branches in the United States don’t do. This allows the agency to do long-term population studies on its astronaut corps.
Sibonga added that NASA’s science is proceeding at an aggressive pace, given the small population and mission schedules, and cited a few examples of research papers on skeletal health and femoral strength as examples.
Hubble nabs a triple shadow transit in this false color image taken in 2004. Credit: NASA/HST.
The planet Jupiter is always fascinating to watch. Not only do surface features pop in and out of existence on its swirling cloud tops, but its super fast rotation — once every 9.9 hours — assures its face changes rapidly. And the motion of its four large Galilean moons is captivating to observe as well. Next week offers a special treat for well-placed observers: a triple shadow transit of the moons Callisto, Europa and Ganymede on the evening of June 3rd.
The view at 19:00 UT/3:00 PM EDT on June 3rd. Credit: Starry Night Education Software.
Now for the bad news: only a small slice of the planet will witness this rare treat in dusk skies. This is because Jupiter starts the month of June 40 degrees east of the Sun and currently sets around 11 PM local, just 3 hours after local sunset. Never fear, though, it may just be possible to spy a portion of this triple transit from North American longitudes with a little careful planning.
The action begins on June 3rd at 15:20 Universal Time as Callisto’s shadow slides on to the disk of Jupiter, to be followed by Europa and Ganymede’s shadow in quick succession hours later. All three shadows are cast back onto the disk of Jupiter from 18:05 to 19:53 UT, favoring European and African longitudes at sunset. The final shadow, that of Ganymede, moves off the disk of Jupiter at 21:31 UT.
The hemisphere of the Earth facing towards Jupiter from the beginning of the triple shadow transit to the end. the red line marks the day/night terminator. Credit: Stellarium.
The following video simulation begins at around 15:00 UT just prior to the ingress of Callisto’s shadow and runs through 22:00 UT:
Triple shadow transits of Jupiter’s moons are fairly rare: the last such event occurred last year on October 12th, 2013 favoring North America and the next won’t occur until January 24th, 2015. Jean Meeus calculated that only 31 such events involving 3 different Jovian moons either transiting Jupiter and/or casting shadows onto its disk occur as seen from Earth between 1981 and 2040. The June 3rd event is also the longest in the same 60 year period studied.
The 1:2:4 orbital resonance of the Jovian moons Io, Europa and Ganymede. Credit: Wikimedia Commons.
Can four shadow transits occur at once? Unfortunately, the answer is no. The inner three moons are in a 1:2:4 resonance, meaning that one will always be left out of the picture when two are in front. This also means that Callisto must be included for any triple shadow transit to occur. Next week’s event sees Callisto, Europa and Ganymede crossing in front of Jupiter and casting shadows onto its disk while Io is hidden behind Jupiter in its enormous shadow. Callisto is also the only one of the four large Jovian moons that can “miss” the disk of Jupiter on certain years, owing to the slight inclination of its orbit to the ecliptic. Callisto thus doesn’t always cast a shadow onto the disk of Jupiter, and we’re currently in the middle of a cycle of Callisto shadow transits that started in July of 2013 and runs through July 2016. These “Callisto transit seasons” occur twice during Jupiter’s 11.8 year orbit, and triple shadow transits must also occur within these periods.
So, what’s a North American observer to do? Well, it is possible to spot and track Jupiter with a telescope in the broad daylight. Jupiter rises at around 9:20 AM local in early June, and the waxing crescent Moon passes 5.4 degrees south of it on June 1st. The Moon stands 30 degrees from the planet on June 3rd, and it may be juuusst possible to use it as a guide to the daytime event. A “GoTo” telescope with precise pointing will make this task even easier, allowing you to track Jupiter and the triple shadow transit across the daytime sky from North American longitudes. But be sure to physically block the blazing June Sun behind a building or structure to avoid accidentally catching its blinding glare in the eyepiece!
The orientation of Jupiter, the Moon and the Sun at 4PM EDT on June 3rd. Credit: Stellarium.
Do the shadows of the moons look slightly different to you? A triple shadow transit is a great time to compare them to one another, from the inky hard black dot of the inner moons Europa and Io, to the diffuse large shadow of Callisto. With practice, you can actually identify which moon is casting a shadow during any transit just by its size and appearance!
A study of three multi-shadow transits: last year’s (upper left) a double shadow transit from early 2014 (upper right) and 2004 (bottom). Photos by author.
Shadow transits of Jupiter’s moons also played an interesting role in the history of astronomy as well. Danish astronomer Ole Rømer noted that shadow transits were being observed at slightly different times than predicted depending on the distance of Jupiter and the Earth, and made the first rough calculation of the speed of light in 1676 based on this remarkable insight. Celestial navigators were also intrigued for centuries with the idea of using the phenomena of Jupiter’s moons as a natural clock to gauge longitude. It’s a sound idea in theory, though in practice, it proved tough to make accurate observations from the pitching deck of a ship at sea.
Jupiter captured near the daytime Moon. Photo by author.
Miss the June 3rd event? There’s still two fine opportunities to see Jupiter do its impression of the Earth-Moon system and appear to have only one satellite – Callisto – on the evenings of May 30th and June 7th.
From there, Jupiter slides lower into the dusk as June progresses and heads towards solar conjunction on July 24th.
Let us know if you manage to catch sight of this rare event!
-Send those shadow transit pics in to Universe Today at our Flickr forum.
