Self-Portrait 10 Miles From a Comet
Holy Periodic Comet Photos! Check. This. Out!
That is a self-portrait taken by the Philae landing craft onboard the Rosetta space probe, when they were just 16 kilometers (10 miles) from the comet 67P/Churyumov–Gerasimenko. You can see the side of Rosetta on the left and the solar panel that’s keeping it powered on the right.
And at the top is the comet itself, magnificent and moody in this high-contrast grayscale composite (two images were combined so that both the spacecraft and comet were exposed well). You can even see a jet emanating from the comet, a stream of gas blown out as ice is hit and warmed by sunlight. Stunning.
Rosetta is nosing closer to the comet, and will release the Philae lander in a few weeks. On Nov. 12, the probe will touch down on the surface of the comet, a milestone in our exploration of space. Judging from the quality of this picture, what we will see on that day will be jaw-dropping.
Why Yes, It Is Exactly Rocket Science!
A little while back I posted an amazing Vine video taken by an astronaut on the International Space Station. It shows the release of the Cygnus cargo resupply ship Janice Voss, which had finished its mission bringing supplies up to the ISS. It was filled with trash, unberthed using the robotic CANADARM 2, then put into an orbit that would drop it into Earth’s atmosphere to burn up over the Pacific Ocean.
In the video, the Voss looks like it goes up, into a higher orbit than the ISS, which I thought might be due to the use of a wide-angle fisheye lens. I also supposed it might be due to the orbit of the ship. Watch the video:
So, what’s going on? I got an email from someone who knows orbital mechanics (but prefers to remain anonymous), and he confirmed my suspicions. To explain, I need to give you a brief intro to orbital mechanics. It’s not like the movies … and let me note that I’m no expert in orbital mechanics, so if I make an error here it’s mine, and not my source’s. I’m also going to leave out some details that are a bit hairy, but if you like, you can read up on how orbital mechanics works. It’s pretty cool.
When an object is in orbit around the Earth, its velocity is dependent on how far it is from the center of the Earth (the orbital radius) and the shape of its orbit. For a circular orbit, the orbital radius doesn’t change, so the velocity is constant. If you increase the radius (its distance from Earth) the velocity slows down, so a circular orbit with a larger size means the spacecraft orbits more slowly.
If you want to get to a higher orbital radius, you point your spacecraft into the direction it’s heading and ignite the rocket. The thrust adds velocity to spacecraft for a short time. But that doesn’t put it in a bigger circular orbit; the added energy stretches out the orbit, making it elliptical. The highest point of this new orbit (called apogee) is above the old circular orbit, and the lowest point (perigee) just meets the old one (the old-fashioned term for this is “osculating,” which means “kissing,” a delightful use of the word).
So what does this mean for the ISS and Voss? They start off moving at the same speed, because they’re connected. Voss faces forward, disconnects, and ignites its thruster. The added energy puts it on an elliptical orbit, and it immediately goes up into a higher orbit than ISS; that’s what we see in the video, and why Voss appears to move away from Earth. That’s because it does move away!
Now, if that’s all there was to it, one orbit later Voss and ISS would meet up once again when Voss reaches perigee. But we don’t want that! The whole point is get the spacecraft away from the ISS. So how did they do that?
Watch the video again. Just before the burn, Voss dips its nose a little bit, pointing it slightly down toward the Earth. So it wasn’t thrusting exactly tangent to its orbit; the rocket pushed it down a bit. That maneuver also affects the shape of the elliptical orbit, changing where Voss will reach perigee, and also dropping perigee a bit lower. One orbit later, when Voss reaches perigee, it will be ahead of and lower than ISS. That prevents any chance of collision, even if the spacecraft loses power; the orbits no longer cross.
That would be the situation forever if nothing changed. However, the endgame here is to drop Voss into Earth’s atmosphere. So, a couple of days later, after engineers made sure everything was kosher, they made a final maneuver. They turn Voss around, so now it’s facing backwards in its orbit (tail first). The rocket is fired again, which drops the apogee of the orbit to inside that of ISS, again preventing a collision. The perigee also drops, and the burn lasts long enough so that at perigee the Voss is inside Earth’s atmosphere.
Half an orbit later Voss reaches perigee, and Earth’s air now has a large drag effect. It steals energy from the orbit, dropping the spacecraft even lower. At that point, atmospheric drag really takes over, and you get the spectacular fireball as the ship hypersonically rams the air in front of it, compressing it, and heating it up hugely. The ship becomes a human-made meteor, and falls into the ocean (where, I suppose, it becomes a human-made meteorite).
I find orbital mechanics fascinating, because it all works following (relatively simple) rules that only seem counterintuitive (I had the devil’s own time understanding this video until I realized the Voss was on an elliptical orbit; the mechanics suddenly became way easier to understand). That’s OK, as long as you don’t fret over the instincts humans have developed over millions of years living on the ground.
Flying into space we put centuries of math to the test … and it works. It works. That to me is one of the most amazing things about science that there is: The Universe obeys a set of rules, and we can figure them out. And in many cases, we truly have.
Britain’s “Best Loved Psychic” and the Very Definition of Irony
File this under “Too Ironic to Describe Without Making Your Head Asplode”:
Briefly, Sally Morgan is a self-proclaimed “psychic” who says she can to talk to the dead, and so on. However, reports on her readings make me extremely skeptical of them, as they sound an awful lot like cold reading. She sells out theaters, charging a fairly healthy sum for tickets (as well as for telephone readings).
Recently, a British skeptic named Mark Tilbrook handed out fliers outside some of Morgan’s shows, simply asking people to think about her methods critically. He never says she’s a faker, fraud, scammer, or anything like that; the wording is polite and matter-of-fact.
After doing this at a few shows, Tilbrook was accosted by Morgan’s husband and son. They threatened Tilbrook physically, made death threats, and used homophobic slurs in their confrontation. There’s video of the whole thing.
Since that went public over the weekend, Morgan has had to go on the defensive (and the offensive, claiming Tilbrook has "targeted" her, though by his own account his actions have not been pushy). She’s made a public statement on her site, saying she has “sacked” her husband and son, who no longer will hold the positions of personal manager and tour manager, respectively. In the statement she apparently doesn't perceive any self-imposed irony, saying:
I have come from a family background that has always been very accepting, many of my friends are gay and I have always felt happy that I am often referred to as a gay icon through my work. I am utterly ashamed and devastated at the behaviour of my husband John and Son in Law Daren and neither of them will have anything to do with my work, my business and right now I honestly have no idea what is going to happen to my marriage.
If she really doesn’t know what the future holds for her, maybe she should consult a psychic.
Last Week’s Lunar Eclipse Seen … From Another Planet
… but none quite like this: The eclipse was observed by the MESSENGER space probe, all the way from Mercury! Normally MESSENGER looks straight down on the tiny world, mapping the terrain that slides underneath it. But engineers saw an opportunity for something neat, so they pointed the camera toward Earth and took 31 images, each two minutes apart, to capture the dance of light:
It’s not often something makes me laugh in delight, but that grainy, lumpy video did. You can see the Earth on the left, all of five pixels wide in the original images (the entire video has been expanded by a factor of two), and the Moon on the right, just barely bigger than a single pixel. The motion of the Moon is too small to detect, but as it passes into Earth’s shadow it dims considerably, disappearing.
Even then, the brightness of the Moon has been multiplied by 25 to make the change more obvious. On Oct. 8, during the eclipse, Mercury was nearly between the Earth and Sun, so to MESSENGER, the Earth and Moon were close to full. But the Earth is bigger and more reflective than the Moon, and would look 50 or so times brighter. I’m not surprised they had to enhance the Moon’s brightness.
MESSENGER was 107 million kilometers (66 million miles) from Earth when it took these images. I think that may be a world universal record for the most distant (terrestrial) lunar eclipse ever seen.
Tip o’ the umbra to Emily Lakdawalla.
What Does 200 Billion Stars Really Mean?
The sheer scale of space is overwhelming. Oh, sure, we have words to make it more palatable, like “light-years”—as if a distance of 10 trillion kilometers is graspable by our puny simian brains.
And when I think about our galaxy, the Milky Way, I know that it’s 100,000 light years across, but that’s just a number, the reality too huge to truly hold in my mind.
But what really gets to me is how many stars are in the galaxy. Astronomers, including me, offhandedly say it has something like 200 billion stars comprising its bulk. Two hundred billion. Written out, that’s
And I look at that, and my brain parses it, dissects it, counts the zeroes, makes analogies, uses scientific notation … all in an attempt to grasp the ungraspable.
So how many stars is that, really?
I have been known, over the course of the past few years, to post pictures of the odd cloud or two. And I do mean odd. Sometimes they’re photos I’ve taken myself (and some of which have been very difficult to identify), sometimes they’re from machines in space, and sometimes from humans in space.
Still, I’m not a cloud chaser per se; you won’t see me hopping in my car and driving hundreds of kilometers to spy a weird cloud formation someone tweeted about, for example. On the other hand, if someone were to tell me they saw something like this nearby, well, I’d think pretty hard about getting my car keys and going for a look-see.
Those are undulatus asperatus (agitated or turbulent wave) clouds, a type of cloud that is starting to get consideration as a wholly new category. From what I can tell, they are formed when there’s rising air that creates wide-spread cloud cover, together with wind shear that blows across the rising air. This can set up gravity waves, where air moves up and down as buoyancy and gravity battle it out, creating long rippling waves that carry the clouds up and down.
You can find out more about this on Slate’s Atlas Obscura blog. I urge everyone to bookmark that blog; it is always a fascinating tour of the weirder and wonderfuller places on our planet.
And let me leave you with this simply jaw-dropping video of undulatus asperatus in action. Make it high-def and full screen, because seriously: Holy wow.
A Typhoon and a Cyclone Are Aiming for Land
Two tremendous storms* are heading for landfall on the other side of the world from the U.S. Both are phenomenally dangerous … yet both are exquisitely beautiful when seen from space.
That is Supertyphoon Vongfong, which is in the Philippine Sea, and on course to hit southern Japan. It’s a Category 5, with wind speeds measured on Oct. 9 as 145 knots (nearly 270 kph). It may weaken slightly before hitting landfall, which would be nice for the people in its path. On Oct. 7, the NASA TRMM satellite measured rainfall near the eyewall of about 10 cm/hr (4 inches/hr).
That image was taken by NASA’s Aqua satellite, designed to study the water cycle of our planet.
That shot of the eye is amazing. Given the perspective (how close the eye is to the limb of the Earth) I’d guess the eye was well over 1,000 kilometers away when he took this picture, perhaps even twice that. He used a wide angle lens, so it’s difficult to be sure. Either way, this shows just how huge this typhoon is.
The other storm is Cyclone Hudhud, currently predicted to make landfall in India on Saturday or Sunday local time:
That Aqua image was taken on Oct. 9. Although not as well organized as Vongfong, it’s still a Category 1 storm (predicted to grow to Category 4) and is expected to hit a heavily populated region of India.** After a devastating storm landfall in 1999, India is better prepared to deal with this type of event. You can read more about it in my colleague Eric Holthaus’ article on Slate.
I’ve been through enough big hurricanes to know how terrifying they can be, and how much devastation they can deal out. It’s jarring and disturbing that the bringers of such terror can be so pleasing to the eye from space.
Distance can bring perspective, but in this case both the beauty and the dread are things worth bearing in mind.
It’s also worth remembering that it’s satellite images (along with data from others like TRMM) that allow scientists to make better predictions of where these monster storms will hit, and how much damage they can bring. The people working on this are saving lives, and billions of dollars. That’s what science can do.
*The general term for storms like these changes depending on location. The NOAA has the best definition I’ve seen:
Hurricanes, cyclones, and typhoons are all the same weather phenomenon; we just use different names for these storms in different places. In the Atlantic and Northeast Pacific, the term “hurricane” is used. The same type of disturbance in the Northwest Pacific is called a “typhoon” and “cyclones” occur in the South Pacific and Indian Ocean.
Vongfong is in the Northwest Pacific, so it’s a typhoon, while Hudhud is in the Bay of Bengal/Indian Ocean, so it’s a cyclone.
**Correction, Oct. 10, 2014, at 16:00 UTC: This post originally misstated that Hudhud is Category 4, but it's predicted to grow to that size.
The Blood Moon Eclipse of October 2014
There are approximately eleventy bazillion pictures of the recent lunar eclipse on the web right now, but a few in particular struck me, and I love to share.
The first is from Teoh Hui Chieh (who took one of the most amazing videos of last year’s annular solar eclipse I’ve ever seen). For the lunar eclipse she was in New South Wales, Australia, and took this phenomenal shot of the eclipsed Moon over one of the dishes of the Australia Telescope Compact Array:
Time’s Up for Astrology
I can’t believe that right now, more than 10 percent of the way into the 21st century, I have to write these words, but here we are:
Astrology doesn’t work.
It really is that simple. I need not go into detail here; I’ve already said what I have to say showing exactly why astrology is wrong; astrologers fail to show there’s any evidence that astrology works even when the tests were devised by astrologers themselves! Astrology has no predictive power, no physical cause to believe it has predictive power, and is entirely explained by psychological effects like confirmation bias (remembering predictions that were right and forgetting the ones that were wrong) and the Forer effect (thinking vague, general predictions apply to you specifically).
Yet astrology still gets far, far more attention than it deserves. Just yesterday, I was appalled to find out that Time magazine posted a credulous puff-piece interview with an astrologer. Just as bad, it was focused on the astrology of the lunar eclipse on Oct. 8.
That’s really galling to me. To take a beautiful and wondrous astronomical event and hang this sort of pseudoscience on it is like spray-painting the wall of the Grand Canyon. It’s defacement.
The Time interview is filled with the standard kinds of vaguely worded claims used by astrologers, like eclipses “end something and they brings [sic] something else. But it really needed to end. … There’s a shock factor first, and then a solution that turns out to be so good that you realize, wait a minute, this is a blessing.”
First, lunar eclipses are worldwide events; everybody on the side of the Earth facing the Moon could see it. How could this astrological attribute possibly apply to every single person? Second, note how vague the statement is. The beauty of it (if you’re an astrologer) is that, ironically, anyone who had anything come to a close in their life—from breaking up with a lover to finishing watching a TV series—could apply it to what they experienced. A prediction that general has no real power of prediction at all.
It goes on and on like that. The worst part is there is no hint of skepticism, no actual investigating, that might show that astrology is nonsense. The story here isn’t that astrology is wrong, it’s that Time magazine would give it any sort of support at all.
I'll note that the article's writer did a second interview with Miller that went up the next day, saying why she doesn't think now is the right time to buy an iPhone 6. Before even reading it, I muttered, "Let me guess. Mercury is in retrograde." Yeah, guess what:
“I’m such an Apple addict, I love everything they come out with, but it’s not the right time,” Miller, founder of Astrology Zone, tells TIME. “I know that everybody wants to buy the iPhone 6, but you’ve got to wait.”
Why? Mercury is in retrograde between October 4 and 25—and that period of cosmic slowing, when the planet appears to be traveling backwards, is notorious for misunderstandings and technological failings.
Sigh. Mercury in retrograde affecting electronics is another slice of astrological folderol.
Look. As I’ve said many times before, it’s not that astrology, as a specific flavor of anti-science, is doing direct damage to anyone—except for separating people from their money.
The real problem is that, like all manners of nonsense, it erodes away our ability to separate what’s real and what isn’t. Today, more than ever before in human history, that ability is crucial for our survival. We have concerted, well-organized, and heavily funded efforts underway to demolish that ability, from global warming deniers to anti-vaxxers to politicians who want to control your body and your wallet.
They don’t need the help, especially not from major media outlets like Time magazine.
And, as always, remember:
Tip o' the Ouija board to Mark Wilkins.
An Eclipse of a Different Kind
Did you see the eclipse last night? Pictures are rolling in on Twitter and Facebook, and they're lovely.
But the night before, on Oct. 7, astrophotographer Steve Knight caught a different kind of eclipse: The International Space Station passing in front of the Moon. He even got video of it:
Cool! He slowed the video down by a factor of 10; the event only lasted 1.3 seconds. To be fair, this is technically called a "transit," when something smaller passes in front of something bigger, and not an eclipse, when the objects are closer in size. But the timing of it was too close to not have fun with it.
Last night, right after the full Moon rose a few hours before the lunar eclipse started, I happened to go outside to check something in my front yard. I looked up (because I always look up) and by coincidence happened to see the space station passing through the sky! It was very bright, and its path took it almost directly overhead. As it moved silently across the sky, I glanced over to the Moon, just a few degrees above the eastern horizon, and then at the Rocky Mountains, to my west. The sparse snow on the tops of a few of the mountains was dimly lit by the Moon, and I realized how magnificent the view from ISS must have been: the Moon to one side, the mountains below. I hope at some point I'll see photos of that.