Fantasy on a Martian Theme
I sometimes wonder what it would be like to stand on the surface of Mars, another world, peering out over an alien landscape. In my mind, my limited knowledge of the scientific reality of such a view wars with the more vibrant images of imagination, producing a compromise that is somehow better than both.
When I close my eyes, and try really hard, it looks something like this:
Waxing Crescent Ceres
Apropos of nothing, please enjoy this lovely mosaic of the asteroid Ceres, created from a series of images taken by the Dawn spacecraft from April 24 – 26, 2015:
Yowza. That’s a big beautiful icy rock.
On the 23rd, Dawn entered its science orbit, settling down after its long approach to Ceres. It’s in a circular polar orbit at a height of 13,500 km over the surface. It takes about two weeks to circle the asteroid once.
Do you have red/green glasses? Try this 3D anaglyph of Ceres, too. It really makes that double impact crater in the middle pop.
I’m very curious to see high-resolution images of the bright spots in the big crater we’ve been seeing, especially over time. There are hints the two spots are actually several blurred together, so it’ll be very interesting to see what they look like. A friend pointed out to me that they’re not as bright as you might think; it’s just that Ceres is really dark. It reflects, on average, about 9% of the light that falls on it. Dawn’s other target, the asteroid Vesta, has a reflectivity of more like 43%!
Anyway, we’ll learn more over time as scientists get a chance to analyze the new hi-res data. It’s nice to see a mission just getting started with a new target even as MESSENGER ends its life on Mercury. Hopefully, the White House and Congress will fund more planetary missions; right now there aren’t any big ones being planned or built. Wouldn’t it be nice to see some Cassini-class missions orbiting a half-dozen outer solar system bodies?
Crash Course Astronomy: Mars
I’m pretty sure I’ve seen every single science fiction movie made about Mars. Angry Red Planet, John Carter, Mars Attacks!, and the best of them all, War of the Worlds (the George Pal 1953 version, duh).
But sometimes, truth is cooler than fiction. The planet Mars may not have wild Victorian civilizations with any princesses named Dejah Thoris, but it has a lot of other amazing features. And the best part? It’s fact, not fiction.
So explore Mars with me in this week’s episode of Crash Course Astronomy: Mars.
Unfortunately, Mars is on the other side of the Sun from us, close enough in the sky that it sets about an hour after the Sun does. That makes it really hard to see, and it won’t be up high enough to spot in the morning before sunrise until later in the summer. But if you want to find more, you can search my blog for posts about the Curiosity rover, and the HiRISE camera on the Mars Reconnaissance Orbiter, and just about Mars itself.
I suspect that’ll be enough to keep you reading until the Red Planet is visible once again.
Blue Origin Makes a Surprise Rocket Launch
I’m a big fan of commercial space—private companies building rockets to get into space. I write about SpaceX a lot, of course, since it is very public about its progress. I don’t write as much about Blue Origin, run by Amazon’s Jeff Bezos, because it’s more secretive, keeping things very close to the vest.
On Wednesday, the rocket lifted an uncrewed test capsule to a height of 93.5 kilometers. The capsule, which is designed to hold up to three passengers, separated cleanly from the vehicle, and landed under three parachutes safely on the West Texas ground.
The rocket itself is designed to land vertically, slowing under thrust and settling down on deployable landing legs. This part of the test didn’t perform so well; the hydraulics for the legs didn’t work, and it presumably crashed. This is similar to the problem SpaceX had with its first attempted landing of the Falcon 9 booster in January.
This is pretty amazing news, and very welcome. The plan is that Blue Origin will offer seats on its capsule in two years, selling tickets for suborbital flights—that is, straight up and down (or, more accurately, a ballistic arc), not going around the Earth as in orbital flight. It eventually plans to build rockets capable of achieving orbit.
The current engine it has designed, the BE-3, uses liquid oxygen and hydrogen and has 110,000 pounds of thrust. It is already working on the BE-4, which will produce 550,000 pounds. That upgraded version will be for its next-generation rocket, Very Big Brother, which will be used to go into orbit. The company expects that to be flight-ready in 2017, and it also has a contract with United Launch alliance to provide the BE-4 engines for the new ULA Vulcan rocket.
I’ll note this test flight didn’t quite reach space, technically. That is (somewhat arbitrarily) designated as 100 km above sea level and is called the Kármán line. But I think getting 93.5 percent of the way is still pretty danged impressive.
These are exciting times for space exploration. Although the U.S. doesn’t have the capability to launch Americans into orbit from American soil, that day is fast approaching. The gap we’re in right now is comparable to the amount of time between the end of the Apollo program and the first Space Shuttle launch. The difference now is that instead of relying on a single (and arguably over complex) launch vehicle, we’ll soon have several to choose from, and they’ll be far less expensive than the Shuttle.
It is my fervent hope that in 10 years we’ll be looking back at this crewed launch gap as a very small stumble on the way to space. And that the number displayed here will also be headed skyward.
NASA Chief Statement on House Budget Bill
As I wrote this morning, Republicans on the House Committee for Science, Space, and Technology passed a nakedly partisan budget authorization bill for NASA that drastically and brutally slashes hundreds of millions of dollars from NASA's Earth Science Division, which studies how climate change is affecting our planet.
Charles Bolden, NASA administrator, issued a statement that is brief, to the point, and clearly states his feelings.
The NASA authorization bill making its way through the House of Representatives guts our Earth science program and threatens to set back generations worth of progress in better understanding our changing climate, and our ability to prepare for and respond to earthquakes, droughts, and storm events.
NASA leads the world in the exploration of and study of planets, and none is more important than the one on which we live.
In addition, the bill underfunds the critical space technologies that the nation will need to lead in space, including on our journey to Mars.
If I were him, I would've laced that with some colorful metaphors, too.
Farewell, Good MESSENGER
Today, sometime around 19:30 UTC (3:30 p.m. Eastern U.S. time), the MESSENGER spacecraft will slam into the planet Mercury at nearly four kilometers per second.
That will bring to an end an astonishingly successful mission, one that was ridiculously difficult to pull off.
Getting a probe to Mercury is hard. Mercury orbits the Sun far faster than Earth does, but, ironically, dropping the probe straight down from Earth would accelerate it too much to achieve orbit. On its way to the inner solar system, MESSENGER had to pass by Earth once, Venus twice, and Mercury three times to match velocities.
And now, after six and a half years on route, and four years circling the planet (totaling more than 4,000 complete orbits), MESSENGER is out of fuel. The gravity of the Sun distorts its orbit, and over time it would crash one way or the other. Scientists and engineers squeezed every last drop of science they could out of the probe, but the time has come. Today it becomes a part of the planet it studied for so long.
And what a mission it had! The MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft achieved so much in its short time around the rocky world. It made the first global map of Mercury, found ice in the poles, sampled its exosphere, discovered why the planet is so dark (it’s painted black by passing comets), found volcanic deposits, and mapped the minerals on the surface.
You can read more in the Related Posts section below, and see what the principal investigator thought were its 10 greatest highlights. The University of Michigan College of Engineering put up a nice little list of facts about it, too.
NASA released a fitting tribute video to the mission. Watch:
It should be noted that the European Space Agency is preparing its own Mercury mission, due to launch in early 2017. But MESSENGER was special; it was the first Mercury orbiter.
There have been so many nights I’ve gone out after sunset and spotted Mercury in the west, hanging over the horizon in the twilight glow. It’s not always easy to see, and there’s some satisfaction in spotting it before the sky is dark.
Right now, Mercury is climbing in the sky again after sunset, and tonight will be very close to the Pleiades, low to the west. Look for it with binoculars but have a care, it’s low. By the time the sky is dark, it’ll be gone.
But if you do catch Mercury, a faint spark in the gloam, take a moment and tip your hat to MESSENGER, a human sentinel that watched over the tiny, broiling, spectacular, and now less-unknown world.
House GOP Wants to Eviscerate NASA Earth Sciences in New Budget
There’s no other way to put this, so I’ll be succinct: A passel of anti-science global warming denying GOP representatives have put together a funding authorization bill for NASA that at best cuts more than $300 million from the agency’s current Earth science budget.
At worst? More than $500 million.
The actual amount of the cut depends on whether some caps enacted in 2011 are removed or not. If they are, then Earth sciences gets $1.45 billion. If not, it gets $1.2 billion. The current FY 2015 budget is $1.773 billion.
Compare that with the White House request for FY ’16 of $1.947 billion for Earth sciences. The bill will be marked up (amended and rewritten) by the House Science, Space, and Technology Committee today.
This, for the space agency which has a critical role in understanding climate change and its effects on our planet.
I'll note that I have many more issues with this bill, including the inevitable funding of SLS and Orion, and some things I like, such as planetary exploration being well-funded ... though that appears to be getting the money Earth sciences is losing. You can read more about that at the Planetary Society.
But the evisceration of Earth sciences means this bill is seriously, critically flawed. I have written about this again and again: Republicans in the House and Senate don’t want NASA studying Earth, because they think (or say) that global warming isn’t real, or isn’t a problem, or whatever talking point they’ve been told to use this week. What they say in statements is that NASA should be looking outward, and other agencies should be studying Earth.
Sounds good, right? But then they pledge to cut that ability from other agencies, too (that particular bill passed, by the way). Pretty transparent.
If you think I’m mad, I am. And so are others; Rep. Donna Edwards, D-Maryland, has pledged to fight the bill, and I hope others Congress members in the House do as well. Cutting NASA Earth Sciences funding is, frankly, disgusting. Much like throwing snowballs in Congress.
Update, April 30, 2015, at 14:30 UTC: It's even worse than I thought. In an op-ed in The Hill, Rep. Eddie Bernice Johnson, D-Texas, wrote that the GOP members of the committee didn't even give the writeup of the bill to Democrats on the committee until very late last week, indicating the GOP members are not operating in good faith on this issue.
So yeah, damn right I’m mad. When you vote for people who publicly and loudly spout nonsense about science, and go against the overwhelming 97 percent consensus among climate scientists, what do you expect?
We sowed this Congress, and this is what we reap. Potentially huge cuts to critical science, care of the GOP. Remember that in November 2016.
Update, April 30, 2015, at 18:30 UTC: Well, that's that. The authorization bill passed along party lines (19 Republicans to 15 Democrats) and will move to the House floor eventually for a vote. Rep. Edwards put in an amendment to restore the Earth sciences budget but was voted down ... again along party lines. So there you have it. If this authorization is upheld by the House, it will be reconciled with a Senate version, and then negotiated with the White House. But for now, the huge and devastating cuts to NASA's ability to monitor our warming planet will be the baseline.
New Horizons Sees Features on Pluto!
At a press conference on Wednesday astronomers working on the New Horizons space probe revealed new images that show surface features on Pluto for the first time!
The probe was just over 100 million kilometers from Pluto when the images were taken on April 12–18 (the Earth is 150 million km from the Sun, for comparison). Hubble images taken over the years have shown the diminutive world has darker and lighter patches on its surface, and these images match that.
In fact, these images are now at higher resolution than Hubble can produce! And they'll be getting better every day ...
Pluto looks lumpy in the animation, but that’s certainly an illusion; darker spots near the edge make it look like Pluto has chunks taken out of it. It’s expected that Pluto will be quite round; its gravity should compress it enough for it to be mostly spherical. I wonder if it’ll be oblate (slightly flattened) due to tides from its moon Charon. We’ll know pretty soon.
Charon can be seen in the animation as well, orbiting Pluto once every six days or so. Actually, it’s about ¼ the diameter of Pluto, and massive enough that it pulls on its parent pretty hard, hard enough that it’s more correct to say they both orbit their common barycenter, their center of mass.
I’ll note these images have been deconvolved; that means they’ve been sharpened using techniques that help bring them into better focus. The raw images look like blurs, but by combining them and using these techniques, the surface features can be detected.
The rotation axis of Pluto is labeled in the animation. Pluto’s spin is tilted compared with its orbit, so the probe is coming into the system nearly “face-on”. Interestingly, as NH Principal Investigator Alan Stern points out, there’s a bright spot on Pluto at the lower right, right at the pole. Is that some sort of ice cap? Maybe. It’s too soon to tell, but in a few months we’ll know better once New Horizons can see features better, and analyze their composition.
Pluto is tiny, just 2,370 km across—our own Moon is far larger (3,470 km). That’s why it still appears so small to New Horizons. The probe is closing in on Pluto rapidly, though, moving at about 14 km/sec. Right now, New Horizons is about 90 million kilometers from Pluto, and 4.7 billion km from Earth. It takes the radio signals from the probe nearly 4.5 hours to get here!
Closest approach occurs at noon UTC on July 14. Even in early June Pluto will only be a little over 10 pixels across, and 100 pixels four days before the encounter. Things will happen rapidly starting then. New Horizons flies through the system in only a few hours, and it’ll take months to send all the data back to Earth. Bandwidth is limited when you’re that far from home.
I'll note that the raw images off the probe are being posted online, too. I suggest checking in on them every day or two, and watch them get better and better as time goes on, and New Horizons approaches Pluto.
I’m very excited about this mission. If they’re getting detail like this now, imagine what we’ll see in July!
A Million H-Bombs per Second Heat the Sun’s Corona
The Sun’s atmosphere—its corona—is far, far hotter than its surface, and this has been a long-standing mystery, baffling astronomers for decades.
This week, astronomers announced they have found the smoking gun. Almost literally.
Here’s the scoop. The Sun is a huge ball of plasma,* gas so hot that electrons are ripped from their parent atoms. It doesn’t really have a surface, instead just sort of fading away with height.
The layer we see is called the photosphere (“sphere of light”), because that’s where the material in the Sun gets thin enough that light can easily fly out. Above this layer is the corona, what you can think of as the Sun’s atmosphere: extremely thin gas.
The thing is, while the photosphere is hot, roughly 5,500° C, the corona is freaking hot, 2 million degrees on average. That’s weird. Inside the Sun, the temperature drops as you move out from the center, but that trend reverses, viciously, at the corona.
Why is the corona so hot?
Astronomers have tried to explain this for years, coming up with lots of mechanisms. But they’re hard to prove or disprove. Observing the corona is difficult; the plasma there is incredibly thin and faint. It’s also so hot it glows at wavelengths of light that don’t penetrate our atmosphere like far ultraviolet and X-rays, so we need space-based observatories to study it (usually; hang on for the important exception).
Also, the scale is a tad mind-crushing. The Sun is more than 100 times wider than Earth, 1.4 million kilometers across, and the corona even larger. There’s not much on the large scale that seems to show why the corona should be so hot.
But there are hints. The Sun has a complex magnetic field, caused by its internal motion, which can generate huge, towering loops above the photosphere. These store unbelievable amounts of energy and when they twist up and tangle, they can snap, releasing that energy as solar flares. These are storms of ridiculous power; a single flare can explode with as much power as 10 billion one megaton H-bombs.
These aren’t the source of coronal heating—flares don’t happen very often—but what if big ones are only (so to speak) the tip of the iceberg? What if there are little ones, lots of them, too small to see?
These nanoflares, as astronomers dubbed them, could pay the solar coronal heating bill, assuming there were enough of them. But they were maddeningly elusive. Astronomers looked, but never saw any.
… until now. Using a combination of different observatories, these nanoflares have finally been spotted. Using EUNIS (the Extreme Ultraviolet Normal Incidence Spectrograph), the nanoflares have revealed themselves. Here they are:
EUNIS breaks up light into its individual colors, allowing astronomers to determine the Sun’s plasma properties, most notably the plasma temperature. The image on the left (teal) shows a small region of the Sun at 10 million degrees Celsius. The middle (pink) is about 1 million degrees, and the right (yellow) a paltry 100,000°—which is still searingly hot, far hotter than the Sun’s surface.
The teal image shows the hottest part of the corona, and you can see those finger-like tendrils above center: Those are the nanoflares, or actually many of them, all overlapping. They still happen on a scale too small to see individually, but their collective nature has finally been seen.
Each nanoflare sounds small, but they’re still incredible: Each explodes with the energy of a 50 megaton nuclear weapon, equivalent to the most powerful device ever detonated on Earth (the Tsar Bomba; read about that if you want to lose sleep tonight), and there may be millions of those going off each and every second on the Sun’s surface.
That’s what heats the corona. Mind you, as powerful as they are they still are dwarfed by the Sun’s normal energy output, which is 100 billion megatons per second. But that heat doesn’t couple with the corona well, which is why the discovery of these nanoflares is so important. And interestingly, the nanoflares are hotter than the corona, too. The physics is complicated, but the astronomers involved in this discovery have models that can help understand this, where the heat transferred to the corona is quickly dissipated. These models, too, are new.
While this is a critical step in understanding the corona’s heat, there’s still a problem: What causes the nanoflares? The idea of smaller scale magnetic loop tangles snapping is a good one, but there are others that may contribute as well. For example, you might expect nanoflares only where magnetic loops are prevalent (where the Sun is active), but observations also show they occur where the Sun is quiet. Clearly, more observations are needed, and more theoretical work to explain them.
This new breakthrough was made using several different observatories, including SOHO and the orbiting NuSTAR X-ray observatory (usually used to look at distant black holes, but which is also sensitive enough to see small-scale eruptions on the Sun). Interestingly, EUNIS was launched on a sounding rocket, a suborbital flight (basically, up-and-down) that lasted only 15 minutes! It’s amazing to think that in that short a time, such a long-standing mystery was finally solved.
… and a new one started. The cause of the flares may take some time to untangle (haha! Get it?) but we have a solid start now. But of course, that’s part of what makes science so much fun. We solve a mystery, and get to enjoy the satisfaction … and then roll up our sleeves and get back to work.
*Some might say it’s a mass of incandescent gas.
Breaking: Russian Resupply Mission to the Space Station in Trouble
Note: Information about all this is still coming in, so regard anything here as tentative. I’ll add updates to the bottom of this article as I get more reliable news
Last night, at 07:09 UTC (03:09 Eastern U.S. time), a Soyuz 2-1a rocket lifted off from Kazakhstan, carrying an uncrewed Progress capsule loaded with roughly 3 tons of food and supplies for the astronauts on the International Space Station.
After separation from the third stage, however, ground controllers got data showing the telemetry was sporadic and that only two of the five communication antennas had deployed. Not long after that it became clear the capsule was spinning rapidly, tumbling once every three seconds.
The original plan was to put Progress on a quick trajectory to meet ISS after just four orbits (about six hours). That was then delayed, setting up a Thursday rendezvous. With the spacecraft spinning, this has now been delayed again, this time indefinitely until the problems are fixed.
Update, April 28, 2015, at 19:15 UTC: Video has been downlinked from a camera on the Progress capsule showing it spinning. Note: I had originally said it was tumbling, which implies a multi-axis spin, but it appears here to be spinning on one axis only, so I changed the wording above. Thanks to JP Major, Ian O'Neill, and Rocket_Woman1 on Twitter for the link.
And there may be a time crunch: Some reports indicate the Progress is in a bad orbit. Instead of a slightly elliptical orbit taking it from 190 to 240 kilometers above the Earth’s surface, the current orbit may be dropping it as low as 124 km, where air is substantially thicker. This puts drag on the vehicle, dropping it lower, where air is thicker, dragging it more … if the capsule is indeed on an orbit with this low a perigee (closest approach to Earth), it may only have a few days before this decay causes it to burn up in the atmosphere. Update, April 28, 2015, at 22:00 UTC: Jonathan McDowell reports the Progress is in a 187 x 259 kilometer orbit, close to what was planned. This means re-entry is not an immediately pending problem, giving controllers more time to assess the situation.
Again, note that the Progress capsule is uncrewed, so no lives are in immediate danger. The astronauts on ISS have supplies for several months (SpaceX sent up a Dragon capsule with supplies just two weeks ago) and more resupply missions are scheduled (SpaceX has one planned for June 19 and another Progress launch is set for Aug. 6).
There have been 20 launches with the Soyuz 2-1a rocket, most successful.* It’s too early at the present time to know what went wrong with the flight.
*Correction, April 28, 2015 at 22:00 UTC: I originally misstated that there had only been two launches of the Soyuz 2-1a. There have been 20.
Update, April 29, 2015, at 14:15 UTC: The Joint Space Operations Center reports that 44 separate pieces of debris have been spotted surrounding the Progress capsule in orbit. It's not clear if they are from the capsule or the booster that put it into orbit. Clearly something very bad happened at some point; perhaps there was a small explosion or a rupture of some kind. The capsule is also rotating at 12 RPM, when it shouldn't be spinning at all. Because of this the ISS docking has been called off. Many attempts were made to communicate with the capsule from ground stations as it passed within range, but all failed. I suspect more attempts will be made, but it seems clear that this mission has failed, and now it's a question of hoping to communicate with the capsule long enough to command a de-orbit burn so it can re-enter over the Pacific (otherwise it will come down sometime in the next month or so on its own, with no control over where). Astronauts on ISS have enough supplies for some time, with the next resupply mission from SpaceX in June.