kottke.org posts about Phil Plait
A recent paper claims that the Universe has 10 times more galaxies than we previously thought: an estimated 2 trillion galaxies covering every single patch of sky visible from the Earth. But that doesn’t mean the Universe is more massive or that it contains more stars. Phil Plait explains:
Now, let me be clear. This doesn’t meant the Universe is ten times bigger than we thought, or there are ten times as many stars. I’ll explain — I mean, duh, it’s what I do — but to cut to the chase, what they found is that there are lots of teeny, faint galaxies very far away that have gone undetected. So instead of being in a smaller number of big galaxies, stars are divvied up into a bigger number of smaller ones.
So how many stars are there in the Universe? The Milky Way contains about 400 billion stars. Some massive elliptical galaxies house more than 100 trillion stars. Estimates of the total number are rough, but it’s probably around 10^24 stars…that’s a septillion stars, a trillion trillion. It’s absurd that we’d be the only planet in the Universe with life on it.
This is a pretty good sentence from Phil Plait:
Clouds are a glimpse into the mighty power of fluid dynamics, complicated equations made real and actual and gorgeous, painted across the sky.
The scientific rumor mill is saying that astronomers in Chile have discovered an Earth-like exoplanet orbiting the star nearest Earth, Alpha Proxima, a mere 4.25 light years away. As they say, “huge if true”.
The hunt for exoplanets has been heating up in recent years. Since it began its mission in 2009, over four thousand exoplanet candidates have been discovered by the Kepler mission, several hundred of which have been confirmed to be “Earth-like” (i.e. terrestrial). And of these, some 216 planets have been shown to be both terrestrial and located within their parent star’s habitable zone (aka. “Goldilocks zone”).
But in what may prove to be the most exciting find to date, the German weekly Der Spiegel announced recently that astronomers have discovered an Earth-like planet orbiting Proxima Centauri, just 4.25 light-years away. Yes, in what is an apparent trifecta, this newly-discovered exoplanet is Earth-like, orbits within its sun’s habitable zone, and is within our reach. But is this too good to be true?
If you read the article, there’s cause for skepticism but an official announcement is coming next week so we’ll know for sure one way or the other.
The other cool thing? If there is a planet there, plans are already underway to build a project to get probes to nearby Alpha Centuri in 20 years, Project Starshot:
In the last decade and a half, rapid technological advances have opened up the possibility of light-powered space travel at a significant fraction of light speed. This involves a ground-based light beamer pushing ultra-light nanocrafts - miniature space probes attached to lightsails - to speeds of up to 100 million miles an hour. Such a system would allow a flyby mission to reach Alpha Centauri in just over 20 years from launch, and beam home images of possible planets, as well as other scientific data such as analysis of magnetic fields.
Perhaps they can redirect their target slightly?
Update: It appears as if the rumors were true. Phil Plait writing at Slate:
The planet, called Proxima Centauri b or just Proxima b (exoplanets are given their star’s name plus a lower case letter in order of discovery, starting with “b”), orbits Proxima every 11.2 days. It has a mass of no less than 1.3 times the Earth’s, so if it’s rock and metal like Earth it’s only a bit bigger. It’s a mere 7.3 million kilometers from the star-a lot closer than Earth’s distance from the Sun of 150 million kilometers!-but Proxima is so faint and cool it receives about two-thirds the amount of light and heat the Earth does. That means that it’s in Proxima’s habitable zone: It’s possible (more or less) that liquid water could exist on its surface.
A man in Germany rigged a camera to take a photo 10 minutes after sunrise every day for an entire year. Phil Plait explains the Sun’s motion:
The video starts at the vernal equinox in 2015, on March 21, and runs through to March 20, 2016. The Sun rises due east, then moves left (north) every morning at a rapid rate. You can then see it slow, stop at the June solstice, and then reverse direction, moving south (right). It slows and stops again at the December solstice (note the snow on the rooftops!), then reverses, moving north again. The weather gets pretty bad, but you can still see enough to get a sense that the Sun moves most rapidly at the equinoxes and most slowly at the solstices, just as I said.
Astronomers are interested in the goings-on around a star in our galaxy called KIC 8462852. There appears to be a lot of debris around it, which is a bit unusual and might have any number of causes, including that an extraterrestrial intelligence built all sorts of things around the star.
Jason Wright, an astronomer from Penn State University, is set to publish an alternative interpretation of the light pattern. SETI researchers have long suggested that we might be able to detect distant extraterrestrial civilizations, by looking for enormous technological artifacts orbiting other stars. Wright and his co-authors say the unusual star’s light pattern is consistent with a “swarm of megastructures,” perhaps stellar-light collectors, technology designed to catch energy from the star.
“When [Boyajian] showed me the data, I was fascinated by how crazy it looked,” Wright told me. “Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build.”
Boyajian is now working with Wright and Andrew Siemion, the Director of the SETI Research Center at the University of California, Berkeley. The three of them are writing up a proposal. They want to point a massive radio dish at the unusual star, to see if it emits radio waves at frequencies associated with technological activity.
Phil Plait has more context on this weirdo star and how the alien angle is pretty far-fetched but also worth checking out.
Two teams of NASA scientists have discovered evidence that hydrothermal vents on the Saturnian moon of Enceladus show signs of “active hot-water chemistry”. Why is that exciting? Because similar chemistry occurs deep in the Earth’s oceans *and* can support life. Phil Plait explains.
We see these vents in the ocean bottom on Earth, too. The water there is very hot, heated by tectonic processes inside Earth’s crust. It brings up minerals and nutrients, and life thrives there. A lot of the processes are the same as what’s imagined is happening on Enceladus; minerals are dissolved in hot water that spews up into the cold ocean, precipitating out. A lot of it is sulfur based, but amazingly life exists there anyway. The environment is highly toxic to humans-huge pressure, boiling water near the vents, freezing a bit farther away, and loaded with icky chemicals-but as a scientist once said, “Life finds a way.”
Between the evidence of past flowing water on Mars, Titan’s hydrocarbon lakes, Europa’s underground ocean, and Enceladus, it seems increasingly probable we’ll find life somewhere else in the solar system. That’s a pretty exciting prospect! (via @ericholthaus)
Update: It was also announced today that the Hubble has detected signs of a salty underground ocean on Jupiter’s moon Ganymede.
New observations of the moon using Hubble support this. Ganymede has a weak magnetic field, and, like on Earth, this generates an aurora-the glow created when high-speed subatomic particles slam into the extremely thin atmosphere. This glow is brightest in ultraviolet, and so astronomers used the Space Telescope Imaging Spectrograph (my old camera!) on Hubble to observe Ganymede. STIS is quite sensitive to UV and detected the aurora.
Now this part is a bit tricky: Jupiter has a powerful magnetic field as well, which interacts with Ganymede’s. As they do, the aurora changes position over time, moving up and down in latitude. However, the observations show that the aurorae do not change nearly as much as expected if Ganymede were solid. The best way to explain this is if the moon has a salty ocean under its surface. The ocean would have its own magnetic field and would resist the influence of Jupiter’s magnetic field, which in turn keeps the aurora steadier.
Turns out there’s water all over the place in the solar system. How about that?
The Hubble Space Telescope was launched 25 years ago, and to start the celebration, NASA has released a pair of images that actually did make this space nerd’s jaw drop. The first is an update of a classic: a much sharper photo of the so-called Pillars of Creation:
Although NASA’s Hubble Space Telescope has taken many breathtaking images of the universe, one snapshot stands out from the rest: the iconic view of the so-called “Pillars of Creation.” The jaw-dropping photo, taken in 1995, revealed never-before-seen details of three giant columns of cold gas bathed in the scorching ultraviolet light from a cluster of young, massive stars in a small region of the Eagle Nebula, or M16.
The second image isn’t so immediately amazing but is my favorite of the two. It’s a photo of half of the Andromeda galaxy, the big galaxy closest to our own in distance but also in rough size and shape. Here’s a very very scaled-down version of it:
The largest NASA Hubble Space Telescope image ever assembled, this sweeping view of a portion of the Andromeda galaxy (M31) is the sharpest large composite image ever taken of our galactic neighbor. Though the galaxy is over 2 million light-years away, the Hubble telescope is powerful enough to resolve individual stars in a 61,000-light-year-long section of the galaxy’s pancake-shaped disk. It’s like photographing a beach and resolving individual grains of sand. And, there are lots of stars in this sweeping view — over 100 million, with some of them in thousands of star clusters seen embedded in the disk.
The original image is 1500 megapixels (1.5 gigapixels!), which is so big that you’d need 600 HD televisions to display the whole thing. But if you take the biggest reasonable size available for download (100 megapixels) and zoom in on it, you get this:
That looks like JPEG compression noise, right? Nope, each one of those dots is a star…some of the 100 million individual stars that can be seen in the full image.
That’s right, Keanu. Whoa. For an even closer look, check out this annotated close-up released by NASA:
If you’re curious and feel like crashing your browser and/or Photoshop a bunch of times (I did not), the full-res Andromeda images are available here. And Phil Plait writes much more joyfully and knowledgeably about these images than I do…go take a look at his Pillars of Creation and Andromeda posts.
Update: Rob Griffiths took 50+ photos from the Hubble web site and made them into Retina iMac-sized wallpapers. (via @djacobs)
Kip Thorne is a theoretical physicist who did some of the first serious work on the possibility of travel through wormholes. Several years ago, he resigned as the Feynman Professor of Theoretical Physics from Caltech in part to make movies. To that end, Thorne acted as Christopher Nolan’s science advisor for Interstellar. As a companion to the movie, Thorne wrote a book called The Science of Interstellar.
Yet in The Science of Interstellar, Kip Thorne, the physicist who assisted Nolan on the scientific aspects of Interstellar, shows us that the movie’s jaw-dropping events and stunning, never-before-attempted visuals are grounded in real science. Thorne shares his experiences working as the science adviser on the film and then moves on to the science itself. In chapters on wormholes, black holes, interstellar travel, and much more, Thorne’s scientific insights — many of them triggered during the actual scripting and shooting of Interstellar — describe the physical laws that govern our universe and the truly astounding phenomena that those laws make possible.
Wired has a piece on how Thorne and Nolan worked together on the film. Phil Plait was unimpressed with some of the science in the movie, although he retracted some of his criticism. If you’re confused by the science or plot, Slate has a FAQ.
Update: Well, well, the internet’s resident Science Movie Curmudgeon Neil deGrasse Tyson actually liked the depiction of science in Interstellar. In particular: “Of the leading characters (all of whom are scientists or engineers) half are women. Just an FYI.” (via @thoughtbrain)
Update: What’s wrong with “What’s Wrong with the Science of Movies About Science?” pieces? Plenty says Matt Singer.
But a movie is not its marketing; regardless of what ‘Interstellar”s marketing said, the film itself makes no such assertions about its scientific accuracy. It doesn’t open with a disclaimer informing viewers that it’s based on true science; in fact, it doesn’t open with any sort of disclaimer at all. Nolan never tells us exactly where or when ‘Interstellar’ is set. It seems like the movie takes place on our Earth in the relatively near future, but that’s just a guess. Maybe ‘Interstellar’ is set a million years after our current civilization ended. Or maybe it’s set in an alternate dimension, where the rules of physics as Phil Plait knows them don’t strictly apply.
Or maybe ‘Interstellar’ really is set on our Earth 50 years in the future, and it doesn’t matter anyway because ‘Interstellar’ is a work of fiction. It’s particularly strange to see people holding ‘Interstellar’ up to a high standard of scientific accuracy because the movie is pretty clearly a work of stylized, speculative sci-fi right from the start.
If the Moon orbited the Earth at the same distance as the International Space Station, it might look a little something like this:
At that distance, the Moon would cover half the sky and take about five minutes to cross the sky. Of course, as Phil Plait notes, if the Moon were that close, tidal forces would result in complete chaos for everyone involved.
There would be global floods as a tidal wave kilometers high sweeps around the world every 90 minutes (due to the Moon’s closer, faster orbit), scouring clean everything in its path. The Earth itself would also be stretched up and down, so there would be apocalyptic earthquakes, not to mention huge internal heating of the Earth and subsequent volcanism. I’d think that the oceans might even boil away due to the enormous heat released from the Earth’s interior, so at least that spares you the flood… but replaces water with lava. Yay?
After many days of analysis by scientists and internet sleuths alike, it’s likely that the thing pictured whizzing by the skydiver in this video is not a meteorite but a plain old rock that got packed in with his parachute. Phil Plait reports:
I actually became convinced last night, when BA Tweep Helge Bjorkhaug sent me a link to a slowed-down version of the video. Immediately before the rock flies past, I saw a second piece of debris just to the right of the skydiver’s parachute strap. It was in several frames, and clearly real.
So yeah, bummer, not a meteorite. But as Plait notes, that’s how science works.
That’s how you get to the truth, folks. Open inquiry, honest investigation, and acceptance of the line of evidence no matter where it leads.
The other day, Bill Nye debated Ken Ham about evolution and creationism. At the event, Matt Stopera asked self-identifying creationists to write question/notes to those who “believe” in evolution. Here’s one:
Phil Plait of Bad Astronomy responded to each of the 22 notes/questions from the creationists. Here’s his answer to the comment above:
I agree; it is amazing! I’ve written about this many times. But we know that complexity can arise naturally through the laws of physics. It doesn’t take very complex rules to create huge diversity. Look at poker; a simple set of rules creates a game that has so many combinations it’s essentially infinite to human experience. We can figure out the rules of nature by studying the way processes follow them, and deduce what’s going on behind the scenes. And whenever we do, we see science.
This makes me think of Richard Feynman’s ode to the scientific beauty of a flower:
I have a friend who’s an artist and has sometimes taken a view which I don’t agree with very well. He’ll hold up a flower and say “look how beautiful it is,” and I’ll agree. Then he says “I as an artist can see how beautiful this is but you as a scientist take this all apart and it becomes a dull thing,” and I think that he’s kind of nutty. First of all, the beauty that he sees is available to other people and to me too, I believe. Although I may not be quite as refined aesthetically as he is … I can appreciate the beauty of a flower. At the same time, I see much more about the flower than he sees. I could imagine the cells in there, the complicated actions inside, which also have a beauty. I mean it’s not just beauty at this dimension, at one centimeter; there’s also beauty at smaller dimensions, the inner structure, also the processes. The fact that the colors in the flower evolved in order to attract insects to pollinate it is interesting; it means that insects can see the color. It adds a question: does this aesthetic sense also exist in the lower forms? Why is it aesthetic? All kinds of interesting questions which the science knowledge only adds to the excitement, the mystery and the awe of a flower. It only adds. I don’t understand how it subtracts.
From Phil Plait at Bad Astronomy, a list of ten things you might not know about black holes. Some of this I knew, but this one is incredible:
If you were to rope off the solar system out past Neptune, enclose it in a giant sphere, and fill it with air, it would be a black hole!
See also this recent tweet from physicist Brian Greene:
Remove all the space within the atoms making up the human body, and every person that’s ever lived would fit inside a baseball.
(via @daveg & @rosecrans)
Phil Plait of Bad Astronomy takes on Steve Jobs’ claim that iPhone 4’s pixels are too small for the human eye to see individually. I have confidence in Plait’s conclusions:
I know a thing or two about resolution as well, having spent a few years calibrating a camera on board Hubble.
He may as well have pulled Marshall McLuhan out from behind a movie poster.