2015年6月30日 星期二
An Unusual Mountain on Asteroid Ceres
Opinions On Falcon Loss Aftermath Are All Over The Map
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NASA TV Coverage Set for Space Station Cargo Ship Launch and Docking
June 30, 2015
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NASA Signs Scientific and Education Agreements with Brazil
June 30, 2015
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Dawn Journal: Ceres' Intriguing Geology
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NASA Astronaut Preps for First Space Station Mission, Available for Media Interviews
June 30, 2015
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Pluto Grows Under New Horizons’ Watchful Eye
Right now, Pluto is about 25 pixels across in the New Horizons space probe’s long-range camera. In a week it’ll be 50 pixels across. A few days later it’ll be well to 100 … and then it’ll grow by the hour.
What will we see? I wrote about all this for my twice-monthly column for Sen.com. Go see! It’s subscription only, but c’mon. I’m worth it.
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Eruption of Wolf Volcano, Galapagos Islands
ISS Daily Summary Report – 06/29/15
June 30, 2015 at 01:00AM
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A Refreshing Illusion: Flat Glass of Water
I love fun illusions, and I happened upon one that’s pretty interesting to see: An artist draws a glass of water that is startlingly 3D:
Oddly, the illusion is actually more convincing to watch at lower resolution and with a smaller window; that washes out the pencil strokes and actually makes the illusion more realistic. I can’t remember the last time I saw something like that.
This type of art is becoming common in street drawing; a web search will yield a bazillion very cool examples.
This technique is called forced perspective, in that it takes the cues your eyes and brain use to estimate relative distance (like, when one object is closer than another) and plays with them, forcing you to interpret those cues a certain way.
When the artist rotates the drawing so the top of the glass is toward you it looks all weird and distorted because your brain is confused. I love the irony; it shows you this is a drawing and not real, yet your brain may take a moment or two to actually settle with that. Our brains just love to be fooled.
My friend and evil twin Richard Wiseman* is a master at this. Watch this video he created:
Richard is a psychologist who studies things like this. I strongly urge you to watch the videos on his Quirkology YouTube channel and to read his books. It’s really good stuff.
... and please check out what I still consider the single greatest illusion of all time.
Tip o’ the Necker Cube to David Darling.
* He claims I’m the evil one, thus proving he’s the evil one.
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2015年6月29日 星期一
5 Steps to Preventing Asteroid Impact
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NASA's Boulder Retrieval Mission
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Quick: Read The Planetary Society Mars Plan While It Is Free
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Falcon Mishap Details Emerge
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NASA Invites Media to Tour VIPR, Aeronautics Research Project
June 29, 2015
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Sen. Nelson Thinks USAF Blew Up Falcon
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We're moving!
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Impact of CRS-7 Loss
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Spirals in the D Ring
Weighing A Galactic Monster
How do you weigh a black hole?
That is, to be more precise (or pedantic), how do you figure out what the mass of a black hole is?
There are actually lots of ways, but they all depend on a very simple law of gravity: If you’re orbiting something (whether it’s a black hole, a star, a planet, or anything else), the closer you are, the faster you’ll go.
If you start there, and make a few assumptions, then all you need to do is observe stuff orbiting the black hole, figure out how quickly it’s moving, and boom. The black hole mass falls out.
Astronomers have been doing this for a long time. Observing stars in motion — literally, watching them physically move over several years — in the center of our own Milky Way galaxy shows that the supermassive black hole residing there has a mass of over four million times that of our Sun.
Another way is to look at the motion of stars and gas in another galaxy. We can’t see their stars moving directly, but as they zip around the central black hole sometimes they move toward us, and sometimes away. That creates a Doppler shift, a shifting of the light emitted toward the blue and red end of the spectrum. The amount of Doppler shift depends on the velocity of the population of stars and/or gas as they orbit, and that means you can get the black hole mass that way. For example, gas in the center of the galaxy M84 was used to find its black hole has a mass of over a billion times that of the Sun!
Now astronomers have used a different way, though based on this same idea. They used ALMA, the Atacama Large Millimeter/submillimeter Array, to look at light emitted by the molecules HCN (hydrogen cyanide) and HCO (there’s no specific formal name I could find for this, but it’s a carbon atom bonded to an oxygen and hydrogen atom) in the galaxy NGC 1097. ALMA is very precise, and they were able to find both the location of the gas and its velocity.
This gas orbits well outside the black hole, and there are stars there too, millions of them. To account for them (because if they don’t, they’ll get too high a mass for the black hole) they used Hubble observations of NGC 1097. They then fit a series of models, each using different black hole masses, to see which one fit the observed velocity of gas best.
Their result: NGC 1097 has a 140 million solar mass central black hole. That’s way beefier than ours. Also a bit higher than previous estimates of 100 – 120 million.
The reason this is important is that a lot of galaxy characteristics seem to be affiliated with how massive the central black hole is. We can only measure the motion of stars and gas near the center of nearby galaxies, but some of these other characteristics can be seen in galaxies much farther away. If we can get good measurements in different ways for nearby galaxies, we can use that to bootstrap our measurements for the more distant ones.
Also, NGC 1097 is a barred spiral galaxy, and for various reasons these can be very difficult beasts to observe and get the mass of their black holes. These new results should help resolve some of those issues.
So there you go. If you want to take the measure of a black hole, you have to see how things behave nearby it. That’s probably good advice for many things in life, but nothing more so than the heftiest single objects in the Universe.
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2015年6月28日 星期日
CRS-7 Launch Update
Following a nominal liftoff, Falcon 9 experienced a problem shortly before first stage shutdown, resulting in loss of mission. Preliminary analysis suggests the vehicle experienced an overpressure event in the upper stage liquid oxygen tank approximately 139 seconds into flight. Telemetry indicates first stage flight was nominal and that Dragon remained healthy for some period of time following separation.
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All the Colors of the Sun
Was Falcon 9 Destroyed - Yes or No?
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NASA Administrator Statement on the Loss of SpaceX CRS-7
June 28, 2015
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Uncrewed SpaceX Falcon 9 Rocket Explodes After Launch
A SpaceX Falcon 9 rocket carrying supplies to the International Space Station exploded about 2 minutes and 20 seconds after launch this morning. No people were onboard; it was an uncrewed resupply mission. The cause is not yet known.
Here is video of the event (launch is at 51:48, the explosion at 54:05):
SpaceX has not released details yet; a press conference is scheduled for no earlier than 12:30 EDT. I’ll update here when I know more.
Looking at the video, the explosion doesn’t release flames, but instead you see a vaporous white cloud blow away. My guess — and I’m no expert — is that this was a pressurized cryogenic tank failure of some kind. But again, we’ll know more very soon.
Update 1, June 28, 2015 at 16:10 UTC: SpaceX CEO Elon Musk just tweeted that it looks like a tank overpressurization event, as I had guessed:
We should know more soon.
The Dragon capsule on top of the rocket had food and supplies for the astronauts on ISS. The three astronauts on board have enough food to last for many months, so they should be OK for now. Also on board the Dragon was an adapter ring for the ISS that would allow future commercial vehicles easier docking access.
This is the first SpaceX failure since they began resupply missions to ISS, but the third overall failure to ISS, including the loss of a Progress vehicle in April and the Orbital Antares rocket in October of 2014. This comes at a time when the Senate has been trying (wrongly, in my opinion) to cut back on funding for SpaceX and other commercial companies, so I expect we'll see statements from those Senators on this event shortly. Read them with a grain of salt. Again, we'll know more shortly. Stay tuned.
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SpaceX Rocket Breaks Apart En Route to International Space Station
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SpaceX Launch and Landing Attempts Today
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California May Make It Harder to Opt Out of Getting Vaccinated. I'm OK With That.
California may be about to pass a law that only allows parents to opt their public-school-attending children out of vaccines for medical reasons. Personal or religious objections will no longer be accepted.
This bill, SB-277, has been approved by the state Assembly, and is going to the desk of Governor Jerry Brown to sign or veto. It’s hard to say what he will do, as he can be unpredictable.
I’m writing this to urge him to sign it. I support this bill.
While this issue can be subtle, when all is said and done I support mandatory vaccines for public school children. I’ve been pretty clear about it:
If you want to rely on the public trust then you have an obligation to the public trust as well, and part of that obligation is not sending your child to a place with other children if they aren’t immunized against preventable, communicable diseases.
Some people want to claim religious exemption from getting vaccinations, but I don’t find this argument compelling:
I do understand that people might have a religious belief against vaccinations. However, I think religious exemptions can and should only go so far. Certainly they stop dead when religion impinges on my rights to have my child attend a school that is safe.
By the by, there are very few religions that preach against vaccination (one exception: the Dutch Reformed Church, and there was a major measles outbreak in one of their communities in the Netherlands in 2013). The idea of a religious exemption is, to me, something of a non-issue. But, in the end, I don’t think there should be a religious exemption, either.
Certainly there should be some medical exemptions; some children are allergic to some of the ingredients in vaccines, for example. But these too are relatively rare.
When it comes to refusing vaccines, the largest group is obviously composed of people who think vaccines are somehow harmful, or that mandatory vaccination is taking away their rights.
For those opposing it because they think vaccines are unsafe, well, they’re just wrong. There’s no delicate way to put that, no cushioning it. The claims of health concerns from anti-vaxxers are long, but completely unfounded. Vaccines don’t cause autism. Andrew Wakefield, whose research is the very basis of the modern anti-vax movement, has been called a fraud, has been shown to be guilty of scientific misconduct, has been shown to have had a massive conflict of interest in his study, has been shown to have acted unethically, and simply to have been wrong. I mean, sheesh.
Vaccines don’t have toxins in them at anywhere near the levels needed to cause problems (as doctors say, dose makes the toxin). Vaccines are effective, their benefits vastly outweigh any small risk, and are a medical triumph.
For those opposing the bill because they are concerned about parental rights, that’s understandable, but limiting parents’ rights is in some cases justified, especially for the child’s health or for the public welfare. In fact, your rights already are limited. As one obvious example, you can’t drive your child around in a car without them in a safety seat if they’re young, or without wearing a seat belt for older kids. Heck, the state has the right to take your child away from you if you are obviously endangering, neglecting, or abusing them… a sad necessity, but a necessity all the same.
If you don’t vaccinate your child, and there is not a medical reason for it, then you are needlessly endangering your child. It’s really that simple.
And it’s worse even than that. You’re also endangering every child who goes to school with your child.
There are a lot of horrid diseases with devastating health effects that we can stop dead in their tracks with vaccinations. Yet we see outbreaks of them all the time in America, and in many cases it’s because people aren’t vaccinating.
This recent bill in California was spurred by the outbreak of measles that occurred at Disneyland in early 2015. But the need for it is far more broad than that.
Governor Brown: Please sign that bill into law. You could be saving a lot of children's lives.
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2015年6月27日 星期六
Stars of a Summer Triangle
The Summer Triangle... Up Close
If you go outside after sunset — and can tear your eyes off of the spectacle of Venus and Jupiter slowly merging in the west — turn around and look to the east. Not long after the sky gets good and dark, you’ll see a trio of bright stars not far above the horizon. Day by day, as summer shambles on*, these stars will be higher in the sky, seemingly strengthening as the season does as well.
This is the iconic Summer Triangle, made up of three of the brightest stars in the sky: Vega, Deneb, and Altair. Straddling the Milky Way, to thousands of amateur astronomer the trio is a sure sign of the season.
I’ve seen countless wide-angle shots of them, placing them in context in the sky, but master astrophotographer Rogelio Bernal Andreo has done something different; taken close-ups of each stars, to show what they look like as individuals:
WOW.
All three are interesting stars. Altair is the brightest star in the constellation Aquila, the eagle. It has a bit less than twice the mass of the Sun, is more than 10 times more luminous, and is located about 17 light years away, making it one of the closest stars you can see with your naked eye. Its brightness is mostly due to its proximity; while it’s physically brighter than the Sun, from a hundred light years away you’d barely notice it.
Vega, in the constellation Lyra, the lyre, is somewhat more massive than Altair, but nearly four times as luminous. Even though it’s 25 light years away, it appears to be a bit brighter than its neighbor. If the name is familiar, try watching the movie (or reading the book!) Contact, by Carl Sagan. In the 1980s, Vega was found to be putting out more infrared light than expected for a star of its kind, and this is due to a vast disk of debris circling the star, possibly due to the collision of comet-like bodies orbiting it. This material is what’s emitting the infrared, and in fact many such disks have been found around other stars.
Deneb, though, is the bruiser of the three. The brightest star in Cygnus, the swan (also called the Northern Cross), it’s a monster. It has 20 times the mass of the Sun, and blasts out light at 200,000 times the rate the Sun does! It’s so massive it will one day become a supernova. At 2,500 light years away, though, there’s not much to worry about. Even if it doesn’t explode in a million years, it’ll still be too far away to hurt us. But it’ll be about as bright as the Moon in the sky!
Incredible, though, that even though it’s 100 times as far as Vega, it’s only a tad dimmer. It really is a brute. In fact, it’s one of the most distant stars you can see with your naked eye, contrasting wonderfully with nearby Altair. If Deneb were as close as Altair, it would shine so brightly you could read by it!
Look at all the stars surrounding the Big Three in Andreo’s photo, though. Each of those is a sun, each with its own particular uniqueness, its own history. The vast majority of them are likely to have planets too… and even then these are just a tiny fraction of the hundreds of billions of stars in the galaxy.
The sky is filled with stars, planets… and stories. Science helps us read them.
* For northern hemisphere observers, that is. The vast majority of people on Earth live near the 40° north latitude line, and for them the stars are highest in August around 10:00 at night local time. For southern observers, they’ll be low to the north in August.
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2015年6月26日 星期五
Planet Aurora
Prepared Statements: Hearing on Replacing RD-180 Engines on US Launch Vehicles
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Sharing Memories of Columbia and Challenger
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Now Let’s Just Call It Marriage
Good.
Read more of Slate’s coverage of same-sex marriage at the Supreme Court.
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Watching Meteors From the Space Station
ISS Daily Summary Report – 6/25/15
June 26, 2015 at 01:24AM
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What Lurks in the Outer Solar System?
Where does the solar system end?
You might think of the solar system as being the Sun, a bunch of planets*, and various asteroids and comets.
But it’s more complicated than that. Nothing in the Universe ever really has sharp boundaries when you look at it closely. And just because some stuff is big and bright, and other stuff faint and distant, doesn’t mean you can just pick and choose where the city limits lie.
Neptune may be the outermost big planet, but there’s a whole slew of icy objects out past it. And some are way, way past it. And, not surprisingly, they’re weird.
What may be surprising is how much these tiny, distant chunks of frozen water plying the deep black have affected the history of our solar system, and even our very planet. A large fraction of your body is water, and a large fraction of that may have come from The Space Beyond Neptune.
How? Why, I’m glad you asked. Let this guy and his loud shirt tell you all about it.
* How many? Oh, roughly a dozen. Maybe fewer.
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2015年6月25日 星期四
Star Trails Above Table Mountain
The why and how of landing rockets
Some of you may have been following our recent attempts to vertically land the first stage of our Falcon 9 rocket back on Earth.
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JSC's Open Innovation Contract Award Free For All
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NASA Invites Media, Social Media to a Space Launch System RS-25 Engine Test
June 25, 2015
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What Is Glittering at Pluto’s North Pole?
As the New Horizons spacecraft nears Pluto, more details are coming into view, and we are beginning to see surface features on the tiny world.
And that means we’ll see things that are… odd. Perhaps “as yet unexplained” is a better term, since we’re seeing these markings for the first time in human history. The press releases have been amazing, but the images released have been enlarged and processed in complex ways to bring out details.
But as the probe gets closer, we can see details without such means. The raw data are posted online within hours of them being transmitted back to Earth, and that means they are available for perusal.
I was looking at a pair of fresh ones taken just today, June 25, at 05:37 UTC (just after midnight, more or less, US time), when New Horizons was just 22.9 million kilometers from Pluto. They’re amazing. Both Pluto and its large moon Charon show all kinds of features, as you can see at the top of this article (the only processing I did was a straight enlargement and a brightness/contrast fiddle). Overall, Charon is much darker than Pluto, but even then surface features are clearly visible.
But that bright spot on Pluto surprised me. That’s near its north pole, and it’s been seen before in earlier images, basically as a splotch. In this image it’s quite obvious.
I wondered if perhaps this was an image artifact, like a particle hit on the detector, but in fact it’s the same in the other image taken 30 seconds earlier. Here are the two shots side by side:
The spot is very small, probably on the same scale as a single pixel or two in New Horizon’s long-range camera. That means a slight change in the pointing can make its shape look different. Remember too this image is enlarged by a factor of about 10, which can play with the shape as well. While the shape you see may not be real, the brightness contrast is.
But the important thing to note is that it’s seen in both pictures. I’ll note too that Pluto was in a different spot in the camera’s field of view, too, so this isn’t some bad lone pixel either, messing with the shot. This bright spot is quite real. Measuring the pixel brightnesses, it looks to be about twice as bright as the surface around it.
Right now, Pluto is only a couple of dozen pixels across in the long-range camera’s view. New Horizons is moving so rapidly that in 10 days Pluto will be twice this size, and will double again five days after that. Features that are tantalizingly fuzzy now will continue to sharpen, and then we’ll see Pluto as it truly is.
Is this spot at the north pole a fresh impact? Is it nitrogen in its atmosphere freezing out as Pluto slowly moves away from the Sun on its elliptical orbit? Is it one big spot or a lot of little ones (like the weird ones we see on Ceres)?
Give it a couple of weeks. Because that's how close we are. After more than nine years and 5 billion kilometers of travel, New Horizons is about to give us quite a show.
Tip o' the lens cap to Karl Battams for noting new images had arrived.
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Of Course I Still Love You, Falcon: New SpaceX Ship Ready to Catch Rockets
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NASA, Microsoft Collaborate to Bring Science Fiction to Science Fact
June 25, 2015
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The 2015 Earth and Sky Photography Winners
The good folks at the World at Night—dedicated to preserving the night sky and raising awareness about light pollution—have announced the winners of the sixth annual International Earth and Sky Photo Contest, and as usual they are breathtaking examples of the art of astronomy.
They are all beautiful, and you should see them all, but I particularly liked “The Enchanted Forest” by Lyubov Trifonova (shown at the top of this article). The aurora sweep across the sky, set against snow-covered trees in Russia. The Moon illuminates the scene while the familiar stars of the Pleiades and Taurus hang nearby. This won first place in the “Beauty of the Night Sky” category. You can tell she had to endure some fairly inhospitable circumstances to get that shot.
I was pleased to see frequent BA contributor Brad Goldpaint take second place in this category as well.
All the images have been put into a video for ease of viewing:
The contest is open to people all ages anywhere in the world, a way to show that the sky belongs to all of us. I really do like TWAN and support them; check out their site and see what they do. The photographs they have there are surpassingly lovely and will give you an appreciation of the natural heritage of our night sky.
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Solar Dynamics Observatory Sees M7.9-Class Solar Flare
Inclusive Astronomy Conference
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ISS Daily Summary Report – 06/24/15
June 25, 2015 at 01:02AM
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A Star Boils Away Its Own Planet, Turning It Into a Megacomet
Hey, remember last week when I wrote about a Neptune-sized planet (called GJ 436b) that orbits a nearby star, and how it may have an atmosphere that’s almost entirely helium? That’s really weird, since the bigger planets in our solar system have predominantly hydrogen atmospheres. We’ve got nothing like a helium-rich planet in our solar system.
I wrote that the planet seemed to have no methane in its atmosphere as it should; that could be explained by a lack of hydrogen, needed to make methane. Astronomers were guessing that the planet orbits so closely to its star that the lightweight hydrogen would get blown away by the star, and the planet’s gravity is too weak to hold onto it. Helium is heavier and the planet can hold on to it better.
But hang on. It takes a long, long time to strip a planet of hydrogen. Billions of years! So, if what these astronomers were supposing is true, maybe, just maybe, GJ 436b is still losing hydrogen now.
Yeah, about that.
Astronomers using Hubble have just announced that they’ve detected a huge cloud of hydrogen around the planet, and the long, curving tail-like shape to the cloud indicates it’s being blown away from the planet by the star.
Huh.
When I got the press release for this, I did a double take. You don’t usually get observational proof of an idea so shortly after it’s first announced! But here it is.
The planet GJ 436b is called a warm Neptune because, at 23 times the mass of Earth, it’s closer to Neptune's mass than it is to Earth or Jupiter, and it orbits the star only a few million kilometers out. From our point of view it passes directly in front of the star, transits it, once per orbit. That’s how it was first discovered; once every 2.6 Earth days the starlight dims a bit as it’s blocked by the planet. The amount of visible light blocked is small, less than 1%, but measurable.
The astronomers observed the star, a red dwarf about 30 light years from Earth, before, during, and after such a transit. They used the Space Telescope Imaging Spectrograph (a camera I helped calibrate!) to observe the star in the ultraviolet, where hydrogen atoms just love to absorb light. What they found is that the amount of UV light they saw from the star dropped precipitously, by over 50%, starting about two hours before the transit, and lasting for three hours after.
Not only that, they could measure the velocity of the hydrogen atoms as they move around the star. Using 3D modeling, the best fit to what they see is a huge cloud of hydrogen around the planet, forming a comet-like tail sweeping out behind it. Here's a the video showing a depiction of the planet and cloud passing in front of the star. The graph below it shows how the UV light gets absorbed by the hydrogen over time.
Most likely what’s happening is that the lightweight hydrogen is very hot due to the planet being so close to the star. The atoms move so rapidly due to heat that they get flung far above the planet, where the light from the star can give them an additional push, freeing them from the planet’s gravity. That push isn’t terribly strong, so they don’t just fly off and away, but instead form a puffy cloud around the planet, and a long tail of material trailing the planet as it orbits. That’s much the same as how comets form long curving tails as they orbit the Sun, too. Anyway, that’s why they see a dip in UV before the planet transits (that’s from the puffy cloud) and for many hours after (that’s the tail blocking the light).
The image at the top of this post gives you an idea of what this looks like. The star is boiling away the planet! Well, part of it, at least. Calculating the amount of hydrogen they see, and how fast it’s leaving GJ 436b, it looks like it would take many billions of years for the planet to lose all its hydrogen (though it’s possible the loss rate was higher in the past). But still, the planet is already billions of years old, so this method has clearly caused a severe depletion of hydrogen, explaining the lack of methane in its atmosphere, too.
I love it when a plan comes together.
All in all, this makes me smile. What’s not to love? A giant planet, skimming the surface of its star, its atmosphere being slowly torn away and trailing behind it, leaving behind mostly helium… which, as I mentioned in the earlier post, will make the planet oddly gray in color.
This is nothing at all like any planet we have hear in our neighborhood. That’s so cool! The goal of science may be to learn as much as we can about the Universe, but the motivation for so many of us is the weird, the spectacular, the alien, the amazing.
This planet is all of those, and more.
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2015年6月24日 星期三
Triple Conjunction Over Galician National Park
NASA Prepares for Future Space Exploration with International Undersea Crew
June 24, 2015
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Dancing Lights Against the Sky
When you look up in the sky enough, you'll see some really, really weird things.
YouTube user QuadeM13 was out riding his bike and noticed a strange light beam flashing and twisting around above a cloud. He stopped and took some video of it, and it's, well, really really weird (warning, some NSFW language is muttered therein):
So what is this thing? An alien beacon? Thor going back to Asgard?
Nope. It's... ice crystals.
Seriously. What's happening here is a wispy cirrus cloud, made up of ice crystals, is being impinged upon from below by a rising cumulus cloud. If the ice crystals in the cirrus are long and needle-shaped, they'll align themselves with the electric field of the lower cumulus cloud, which is generated by up- and downdrafts inside the cumulus cloud. When the electric field suddenly changes (due to, say, lightning discharges inside the cloud), the ice crystals can snap into a different orientation, reflecting and refracting sunlight in a different direction (note that the plume in the video is the same color as the Sun). They do this as a group, making it look like huge coherent structures are suddenly changing shape.
In the video the flare is pretty bright, and I imagine it would be easy to be freaked out by it. I watch clouds a lot and I’ve never seen this, so I doubt it’s terribly common; you need the right circumstances of the cumulus cloud rising into an icy cirrus layer as well as the right geometry to get the sunlight flashing of the crystals.
Back in 2011, I wrote this very odd phenomenon. I had to do some sleuthing to find out what was going on, but what I didn't know at the time is that they're called “crown flashes”. That would’ve made it a lot easier to find out more!
I found a letter to Nature magazine from 1971 describing the phenomenon, so people have been seeing this for a while. A web search on “crown flash” turns up lots of interesting pictures and videos, too.
The Internet makes finding weird things like this so much easier. I’ve been able to identify iridescent clouds, pileus clouds, and many other weird atmospheric phenomena with just a few clicks. Like any other tool, the ‘net can be used for ill or for good. I’m glad that it can help us see — and understand — the amazingness all around us all the time.
Tip o’ the Faraday cage to photographer Jerry Lodriguss.
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Lights of An Aurora From the International Space Station
ISS Daily Summary Report – 06/23/15
June 24, 2015 at 01:03AM
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What to expect when you're expecting a flyby: Planning your July around New Horizons' Pluto Pictures (version 2)
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Like a SciFi Sunset: Three Crescent Moons Over Saturn
Every time I think I’ve seen the most amazing picture from the Cassini Saturn probe, it sends back something even more devastatingly spectacular.
Like this shot of three crescent moons huddled in the black sky!
Are you kidding me?
Wow. This image was taken on Mar. 25, 2015. The big one is Titan, the one to the upper left is Rhea, and the little one is Mimas. Titan has a thick atmosphere, thicker than Earth’s, composed mostly of nitrogen (also like Earth’s). Sunlight hitting that air gets bent around, sent around the limb, so the crescent appears to wrap farther around the moon than it would otherwise. Mimas and Rhea are airless, so their crescents look much like the familiar one we see every month from our own Moon.
All of Saturn’s big moons orbit the planet almost exactly above its equator, so when the spacecraft’s orbit crosses that plane, the moons can appear to be close together due to perspective even when they’re hundreds of thousands of kilometers apart. The Sun is just off to the lower right in this shot, setting up the correct angles to get this spectacular and breathtaking scene.
Seriously, this looks like it came right out of a scifi movie. But it’s real. Those are worlds, real actual places, ones we can explore and understand.
And we have: Titan has a methane cycle on it much like Earth’s water cycle; the simple molecule can be found in clouds over the surface which rain it out as a liquid, forming rivers and giant lakes, where it evaporates to form clouds once again.
Mimas has a gigantic single crater named Herschel that makes it look like the Death Star. Though it was almost more like Alderaan: Had the impact that formed Herschel been much larger, it would’ve shattered the moon.
Rhea has deep canyons covering one hemisphere, giving it a wispy fairy-tale look, but they are actually the walls of steep canyons caused by deep fractures in the surface.
I love science fiction. It’s inspired me over the years, given me a glimpse into places we can only imagine.
But I love science more. It shows us these places as they actually are, and reminds us that clearly, Nature is far, far more imaginative than we are.
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NASA-Developed Air Traffic Management Tool Flies Into Use
June 23, 2015
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2015年6月23日 星期二
Sharpless 308: Star Bubble
Advising NASA on the Soon-to-be-Redirected Asteroid Redirect Mission
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NASA’s Chandra Captures X-Ray Echoes Pinpointing Distant Neutron Star
June 23, 2015
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Flying Over An Aurora
Pluto Grows in Size While Its Moon Sports a Dark Cap
New Horizons is approaching Pluto and is now just over 20 days from closest approach. Every day the tiny world looks a wee bit bigger to the space probe, which is screaming toward Pluto, getting closer to it by 14 kilometers each and every second.
New images just released are showing more detail, as you can see in the images above. These have been carefully processed to enlarge and enhance those details. Note that Pluto is almost certainly very round, but it looks misshapen due to darker features near the edge blending into the black background.
Pluto is severely tilted with respect to its orbit around the Sun; while the Earth is tilted by about 24°, Pluto is flipped over at about 120°. Because of this and its approach angle, New Horizons doesn’t see the entire surface of Pluto, but it does see more than half as Pluto rotates. Projecting forward, scientists know which part of Pluto will be under the probe’s cameras when it passes, and they can see that part of the surface is richly diverse, sporting lots of different features. This promises some pretty exciting pictures come July …
But we’re learning more all the time. Charon is Pluto’s big moon, more than half the diameter of Pluto itself. Yet it’s very different; as you can see in the video above it’s far darker than Pluto, and therefore likely to have less ice on its surface to reflect sunlight. Also, weirdly, its north pole is darker than the average of the rest of its surface! That’s very interesting. On Earth, water and land are dark, but ice is bright, and the icy poles are brighter than average. Pluto too has a bright north pole (it’s not certain what it is, but it could be frozen nitrogen, not water). Why is Charon’s pole so dark? What different processes are at work there than on its larger partner?
We’ll find out soon enough. Right now, New Horizons is less than 25 million kilometers from Pluto. At closest approach it’ll zoom over the surface at distance of less than 14,000 km! And every day, every hour, between now and then this new world grows under the spacecraft’s eye, getting larger and revealing more detail, more secrets invisible from Earth.
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New Horizons update: Resolving features on Charon and seeing in color
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Yet Another Hearing on Russian Engines
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More False Memories About the Origin of SLS
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NASA, Partners Test Unmanned Aircraft Systems
June 23, 2015
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ISS Daily Summary Report – 06/22/15
June 23, 2015 at 01:02AM
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What Do We Do About Misogyny Online?
Not surprisingly, the issue of misogyny on the Internet has hit the news again.
The blatant and horrid misogyny women face online has been an issue for as long as there’s been an Internet. Recently, though, with the advent of GamerGate, it’s been amplified to a terrifying degree, with women receiving organized attacks, including death threats.
There’s also the problem of doxxing (publically listing a person’s information like phone number and address), which has also led to SWATting: calling the police with a fake claim of (say) a hostage situation, giving the address of the person you’re targeting. The police raid that person’s house, and this can lead to incredibly dangerous situations, and severe psychological harm.
John Oliver did a typically brilliant report on all this for his show “This Week Tonight” on HBO Sunday. Watch:
I’m very glad he tackled this; it gives this issue a wide audience, and I think it’s very important that people with a soapbox use it to help those who may not have as loud a voice.
There’s a trick in our brains that makes all this hard to fight: We tend to listen to people who are like us, and not listen (or not listen well) to those who aren’t. In this case, that means that some men may not hear this message from women talking about it. But if a man says the same thing, it gets traction. I hate that this is the case, but it means these groups can use vocal advocates, allies, among men.
That’s why I write about this as well. I’m a middle-aged white guy, and pretty much the bulls-eye demographic for a lot of the problems faced by women, minorities, and other marginalized groups. My hope is that if I speak up, others will as well.
As I’ve done before, I’ll make this simple. Men (and anyone, of course): Don’t do this. Don’t threaten, harass, doxx, or SWAT. It’s grossly, morally wrong.
I’ll note it’s also massively ironic, since it so face-palmingly proves the point that we really do need feminism.
If you’re worried about doxxing and SWATting, then I suggest you bookmark the Crash Override Network website — created by harassment survivors — and especially their resources page, which focuses on prevention and supporting victims.
Here are other articles I’ve written on this issue. Some advice: Don’t read the comments, unless you need yet more proof of Lewis’ Law.
Science Advice and Sexual Harassment
#YesAllWomen
The Silencing of Hate
Shirtstorm
Harassment as Art
I Stand with Emma Watson
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2015年6月22日 星期一
It Takes More Than Hype To Get To Mars
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NASA Signs Agreement with Space Florida to Operate Historic Landing Facility
June 22, 2015
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A Ceres of Weird Events
Ceres keeps getting weirder.
Those white spots on the surface we’ve been seeing for months are still mystifying, and we can now add another bizarro surface feature to the list: A huge 5 km tall mountain sitting in the middle of an otherwise relatively flat part of the asteroid.
Um. Why is that there?
On Earth, mountains can form for several reasons. Continents crash together, creating wrinkles in the surface. That’s what the Himalayas are. Of course, Ceres doesn’t have plate tectonics! That wouldn’t form a solitary mountain anyway.
Volcanoes? Well, we do see that happening on Earth. But we don't see any other features like this at all nearby, making it unlikely to be from a weak spot in the crust. Devil’s Tower in Wyoming is similar to this feature, though; that tower may have been created by upwelling magma seeping into prehistoric sedimentary layers. But clearly that’s not going to happen on an asteroid! Sedimentary rocks would be, I expect, rather difficult to produce.
Mountains on airless bodies like asteroids (or our Moon) can be made in several ways as well. Giant impacts have mountain ranges around their rim, created by rock lifted up at the edge of the crater. But this mountain on Ceres is alone.
Smaller craters can get central peaks, where the rock rebounds upward after the initial impact (similar to the drop that splashes up in the center of a glass when you pour milk). But there’s no obvious crater around this mountain. Maybe other forces filled it in, or subsequent impacts eroded it away. There's evidence of landslides on the surface as well, which could eventually erase the features of a crater. This seems most likely to me. We've seen other craters on Ceres with central peaks, but I don't think any yet this size. Given all the evidence, though, this is the way I'd lean.
But I’m simply guessing. We’re just now seeing this strange feature, and it’ll be a while, I suspect, before planetary scientists can get enough data to understand it better. Note that Dawn, the spacecraft now orbiting Ceres that took this picture, is still in a relatively high surveying orbit, 4,400 km above the surface. It’ll be dropping down to get much higher resolution images in the coming months.
Hopefully then we’ll get some definitive answers to these mysteries. Ceres is odd. We know there’s ice under the surface, and there’s evidence it also has geysers, eruptions of water, from its surface. That might explain the white spots, too, but there’s still a long way to go to figure all this out.
Ceres is the largest asteroid in the asteroid belt (some call it a dwarf planet; I find the term not terribly useful). It’s unique in that sense, and big enough to have geological processes on it and in it we haven’t fully grasped yet. It’s not Earth, for sure, but it’s far more than a simple monolithic rock in space.
It’s a world. And with a surface area of nearly 3 million square kilometers, there’s a lot of it to explore.
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Media Invited to Tour Journey to Mars Exhibits with Senior NASA Leaders
June 22, 2015
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NASA Selects Six Wild Ideas in Aviation for Further Study
June 22, 2015
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Dawn Survey Orbit Image 11
Are Volcanoes Still Erupting on Venus?
There are a handful of known currently tectonically active objects in the solar system: Earth, of course, plus Saturn’s moon Enceladus, Neptune’s moon Triton, Jupiter’s moon Io (the actual most active body known) and (most likely) Jupiter’s moon Europa.
And now we may be able to add Venus to that list. New evidence strongly suggests there are currently active volcanic vents on the surface of Earth’s sister planet.
I’m actually pretty chuffed about this. We’ve had tantalizing evidence for years that something is bubbling and brewing just beneath Venus’s surface. The top of the mountain Idunn Mons is clearly hotter than surrounding terrain, for example. Lava flows have been seen to be warm as well, and they are certainly less than 2.5 million years old, and possibly far less. Sulfur dioxide, a known volcanic gas, has been seen to spike in abundance then fade with time, which looks very much like a volcano outgassing (though it could simply be due to shifting winds).
But new results from an old mission provide what may be the most important evidence yet that Venus is still puffing away: The ESA Venus Express probe, which completed its eight-year mission last year, found several hot spots on the surface of the planet, and they were all located in rift zones; radial cracks around a volcano where, on Earth at least, magma is pushing up on the surface and flowing out.
Better yet, these hot spots flashed into existence and then faded away over the course of a few days. This is exactly the sort of behavior you’d expect from ongoing volcanism.
Observing the surface of Venus is difficult because of its thick, opaque atmosphere (a product of a runaway greenhouse effect). The observations were at the limit of what the camera could do, but Venus was accommodating by providing really big temperature spikes: one may have reach over 800° Celsius, 350° higher than the surface average.
The camera’s field of view is large, so the resolution is low, but it’s possible these hot spots may be as small as a square kilometer. All in all, these really sound like lava eruptions to me. I’m no expert, of course, but then the people who did the research are.
Studying Venus is important. In many ways it’s very much like Earth. It’s roughly the same size and mass, which means the same density, and that implies we have similar compositions. So why is Venus so blisteringly different? Compared to us, we can ask, “What went wrong?” Why is its crust so thick? Why did the greenhouse effect run away there, and not here? Why does Venus appear to have a surface that’s everywhere the same age, as if a globally catastrophic event repaved the entire planet?
Looking to other planets to understand our own is a critical part of planetary science, and given the current state of Earth’s atmosphere, it’s something we must do. Together with studying our own planet (something the current Congressional majority is dead set against, for some odd reason) these are matters that are critical to our own survival.
That’s why these new results of an extant volcanic Venus are so exciting. That, plus the more purely scientific reason that it’s just plain cool. Venus gets closer to Earth than any other planet in the solar system, yet still hides many secrets. What more is there to learn about it?
I’ll leave you with this, my episode of Crash Course Astronomy about Venus. I wonder how many of the questions raised in it will be answered in the coming years?
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Preparing America’s Spaceport for NASA’s New Rocket
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2015年6月21日 星期日
Rings and Seasons of Saturn
Planetary Science Trash Talking
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To Pluto
Why is it so many of us are excited about the New Horizons mission to Pluto?
This. This is why.
That video was created by Erik Wernquist, the brilliant mind behind Wanderers, what I consider one of the best paeans to exploration ever made.
And like Wanderers, all the places in the New Horizons video are real. We see Venus; Mars (flying over Valles Marineris; a rift valley that dwarfs the Grand Canyon); volcanoes of sulfur erupting over the moon Io as Jupiter and its Red Spot hove into view; the two-faced ice moon Iapetus, stained with organic compounds, revealing the magnificence of Saturn as we slide by; Uranus, its atmosphere a teal green from the presence of methane; Neptune and its moon Triton, with its geyser-like eruptions of nitrogen blasting into its extremely tenuous atmosphere…
… and then Pluto. As I write this, just over three weeks before the New Horizon probe pierces the tiny world’s region of space, we still only have fuzzy pictures of Pluto, a mere dozen or so pixels across. Astronomers have many ideas on what we’ll see when the spacecraft sends back its images over the staggering vastness of five billion kilometers of solar system, but the bottom line is we don’t know exactly what we’ll find.
If we did, it wouldn’t be exploration.
You can follow along with this journey using the Pluto Safari app, and of course by keeping tabs on the New Horizons website.
This is more than just terra incognita. It’s spatium incognita. Whether you think Pluto is a planet or just the biggest of the Kuiper Belt Objects, it’s a marvelous step in our exploration of the solar system.
And we’ll be seeing it for the very first time in the history of all humanity, very, very soon.
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2015年6月20日 星期六
Vulcan Is an Angry God. A Very, Very Angry God.
On April 22, 2015, the Chilean volcano Calbuco erupted, providing the most dramatic and awe-inspiring photographs I’ve ever seen of such an event.
On that day, photographer Martin Heck was right on the scene, by happenstance taking time-lapse footage on the neighboring Osorno volcano. When Calbuco went off, he hurriedly set up and shot video that is, no exaggeration, some of the best I have ever seen of any volcanic eruption ever.
Seriously. Make this full screen and high-definition. It’ll blow your socks off.
Wow. There’s a 4K version of this there, too.
Even better, there were no reported deaths or injuries, despite the huge scale of the eruption. It lasted for well over an hour, and launched a plume 10 kilometers into the sky.
Oh, that plume. The superheated ash and gas are buoyant, so they rise rapidly in a column from the volcano’s vent. The cloud cools as it rises and stops rising when it reaches an altitude where its density equals that of the surrounding air. However, the plume below is still pumping material into that spot, so the cooler material spreads out, forming the mushroom cloud shape. Once the eruption stops, the winds sweep the column to one side.
On top of that, the eruption occurred near sunset, so the low Sun illuminated the cloud from the side, adding more drama. The Sun reddens as it sets, and the ash in the air scatters blue light away, making the cloud appear an unearthly red. At the very end of the video, you can see lightning erupt in the cloud, the result of huge static charges that build up when the sharp, glassy ash particles rub against each other in the turbulent rising column, then suddenly discharge their colossal energy.
This is one of nature’s most impressive terrestrial events, and it unfolds here for you to watch in all its terrifying glory.
You can see more of Heck’s amazing work at his site, Timestorm Films.
Tip o’ the caldera to Joe Hanson at It’s Okay to Be Smart.
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