Category: Top Post

The Neroes of global warming

By Phil Plait | November 2, 2012 7:00 am

Nero was an emperor of Rome, and not looked upon kindly by history. A great fire swept through Rome, rumored to have been started by Nero himself to clear more land for his own estate. Nero supposedly did little to stop it, which is why we have the phrase "Nero fiddled while Rome burned".

The analogy to climate change is glaringly obvious. The burning of fossil fuels such as coal and oil has dumped vast amounts of carbon dioxide into the air – far more than the total from all volcanoes combined, for example. This greenhouse gas essentially traps heat*, preventing natural physical processes from letting the Earth maintain its temperature. The end result: the Earth is heating up.

The vast, overwhelming majority of real climate scientists agree with this assessment. Oddly, the fossil fuel industry doesn’t. They sponsor a lot of very loud and very wrong "think tanks" who deny the very existence of the problem the industry itself created. So the Earth heats up, and they fiddle with the truth.

As I wrote recently, global warming is in the news because it’s very likely that the hurricane Sandy was influenced by our changing climate. I’m not the only one to think so. Climate scientist Randy Horton says, for example, that melting sea ice and a declining jet stream may have been in part responsible for steering Sandy into the east coast, instead of over the open ocean as late-season hurricanes usually do.

The deniers, of course, are spinning this faster than the hurricane itself.

Those of us on the side of reality in this issue want it to be about science, but we must see that it’s about politics. When a large number of sitting members of the US House of Representatives science committee are avid and avowed global warming deniers, this is about politics. When we see the fossil fuel industry funding those very people, it’s about politics.

Perhaps that stranglehold of political denial is loosening up a tiny bit. Business Week, not usually known for leftist leanings, just published a story called "It’s Global Warming, Stupid" and put it on their front page. The two presidential candidates have hardly talked about it, and not at all in the debates, despite this being the biggest medium-term crisis the world is facing. President Obama did finally speak out, on MTV of all places (which is actually pretty good; hopefully a younger audience will listen), but could’ve put in a lot more details of what he actually plans to do.

Of course, Governor Romney is wearing his past statements like an albatross around his neck. He has mocked global warming, and said many times he would dismantle FEMA. He flip-flopped on that just this week, kindof, saying FEMA does an important job. However, given that he said it was "immoral" – his word – to fund FEMA, I have a difficult time believing he’s being entirely honest now.

Because the issue was ignored in the debates, Science Debate put on a mock 4th Presidential debate dealing with global warming, with candidate stand-ins talking about the issue. If only that had been real. If only.

So we still have a long way to go. Things in the Senate aren’t much better, with people like James Inhofe (R-OK) still sticking by his claim that the very idea of global warming is a hoax. Happily, some people are willing to hang that one around his neck, too. But it’s not enough. Not nearly.

And there’s more bad news. One of the biggest weapons we have against hurricanes like Sandy is our fleet of weather satellites, tracking the storms and allowing scientists to predict the path and ferocity of storms, sometimes days in advance. Sandy’s track was predicted amazingly well due to this. But our very ability to do this is in jeopardy: the New York Times is reporting that we may be facing a weather satellite crisis, with an aging fleet of satellites breaking down and no replacements ready for launch for quite some time. There may be a years-long gap in our coverage of storms from space because of this.

And during all of this, the deniers fiddle. They argue and spin about statistics, misleadingly plotting data. They talk about sunspots, they talk about cycles, they talk about other planets, and all the while they are desperately trying to distract you from the real issue. The Earth is warming up, the change is real, it’s dangerous, it’s already affecting us noticeably, and we’re not doing anything to stop it.

The public is catching on to this. Recent polls show that Americans are more accepting that global warming is real. That’s good news, and an excellent start.

But it must be translated into action. We have an election coming up in a few days. Many of these climate change deniers are up for re-election, while others are seeking office. If you are an American, I urge you to do your research and vote accordingly. Literally, our future is in our hands.

<em<Image credit: NOAA/NASA GOES Project


* Technically, CO2 is transparent to visible light, but opaque to far infrared. Sunlight gets through, warms up the ground, which then radiates that heat as infrared. The CO2 won’t let that radiate away into space, so the heat stays on Earth, warming the ground (and oceans!) further. But saying "it traps heat" is close enough.


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Look! Up in the sky! It’s…it’s… it’s an amazing optics display

By Phil Plait | November 1, 2012 7:00 am

It’s funny what tiny little ice crystals can do. Floating high in the air, suspended by air currents, they hang there… and then a ray of sunshine enters them. The light gets bent due to complicated physics, the interplay of that beam of light passing from air to a solid crystal and out again. But once that beam leaves, the sky can light up with a wizard’s pattern of colors and shapes. And if you’re very, very lucky, you’ll see something that you’ll remember the rest of your life.

Something like this:

Holy diffractionation! [Click to heliocanesenate.]

Mind you, this picture is real. David Hathaway – appropriately enough, a solar physicist at NASA’s Marshall Space Flight Center in Huntsville, Alabama – took it using a wide-angle lens to get the whole thing. It’s a High Dynamic Range shot, meaning he combined pictures with 3 different exposure times to see both faint and bright things simultaneously. He took the shot on October 30, 2012.

Everything you’re seeing here is pretty well understood: they all have a name and a specific set of circumstances under which you can see them.

The Sun is the bright blob near the horizon. It’s circled by the 22° halo, a fairly common optical effect in the winter; I see dozens every season. On either side of the Sun are parhelia, nicknamed sundogs. Those are the teardrop-shaped rainbows. Sometimes, as seen here, these stretch out into long streamers called parhelic circles. They are parallel to the horizon but in this wide-angle shot the shape is distorted, bending them up.

Directly above the Sun, dipping down to touch the halo (the math term for this is osculating, which means kissing) is a gull-wing curve called the tangent arc. Above it, connecting the "wings", is the Parry arc.

As an aside, I’ve seen tangent arcs only twice in my entire life. One was at a University of Virginia football game in the winter when the Sun was setting. It was so bright and looked so much like a V that I joked that it was a sign we’d win the game. Georgia Tech trounced us. So much for divination using signs in the sky.

Above the tangent and Parry arcs is a faint rainbow (well, it’s not caused by raindrops, but it’s broken up into colors and has the familiar rainbow-shape) called the Parry supralateral. Faint and off to the right, nicking the supralateral, is a tightly-curved rainbow called the Parry infralateral.

Amazingly, there are still two more to go! The upside-down rainbow at the top is called a circumzenithal arc, because it’s centered on the zenith, the point directly above your head.

Finally, the last thing I can see is a very faint white vertical oval on either side of the the 22° halo and going off the top of the frame, past the circumzenithal arc. That’s the heliac arc, something I’d never even heard of before looking it up here. That’s a new one for me.

Amazing, aren’t they? And get this: there are lots more kinds of phenomena like this, and they’re all caused by ice crystals in the air! The crystals have different shapes – some are flat, some barrel-shaped, so they bend light differently, and their orientation to us causes all these fantastic displays.

By coincidence, just a few days ago BABloggee Joe DePasquale (who works at the Harvard Smithsonian Center for Astrophysics) also saw an aamazing display. Here’s one of the shots he sent me:

Wow. You can see a lot of the same features as in David Hathaway’s picture, too (in fact, Joe made a diagram so you can see what’s what). BABloggee Alan French let me know that there’s a fine gallery of them on Flickr, too.

It’s possible some of this was due to ex-Hurricane Sandy getting moisture high in the atmosphere where it could freeze into crystals. But I’ll note again that I have seen many of these same haloes myself. Most are not rare at all, and all you need to do is keep your eye on the sky. Seriously, one of the first things I do on any day where there are high clouds is look near (not at!) the Sun and see if there’s anything to be seen.

Usually there isn’t. But sometimes, just sometimes, you get that amazing display that makes all the fruitless searching totally worth it.

Look up! There’s a whole Universe out there. And some of the coolest stuff is really close to home, literally just over your head.

Image credits: David Hathaway; Joe dePasquale, used by permission. Tip o’ the Snell’s Law to SpaceWeather.com and to Elwood Herring for pointing it out to me.


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CATEGORIZED UNDER: Cool stuff, Pretty pictures, Top Post

Saturn storm cranks the heat WAY up

By Phil Plait | October 26, 2012 7:00 am

In late 2010, amateur astronomers discovered a white spot on Saturn – a gigantic storm forming in its northern hemisphere. The storm grew rapidly, and within weeks had embiggened to an almost unbelievable size, much larger than our entire planet. The winds in Saturn’s atmosphere sheared the storm, pulling it apart while it still raged, and after three months the storm had wrapped completely around the planet, stretched to the ridiculous length of 300,000 km (180,000 miles) – 3/4 of the distance from the Earth to the Moon!

By mid-2011 the storm had nearly subsided – its remnants could still be seen in images taken by the Cassini spacecraft orbiting the ringed world – but the teeth had been taken out of it. Still, there was one surprise left in it.

Observations taken in the infrared by Cassini as well as from Earth show that the storm was not just big and violent, it also formed a vortex (a storm within a storm, if you like) that got hot – well, hot for frigid Saturn, that is. In the heart of the system, the temperature rose by an incredible 80° Celsius – a difference in temperature that’s like starting in the depths of winter in Anchorage, Alaska and then going to the height of summer in the Sahara!

The image here [click to encronosenate] is from the Very Large Telescope in Chile, and was taken in the infrared, where the heat in the vortex is fairly obvious. Mind you, it’s not like it was a firestorm: the maximum temperature was still a chilly -150° Celsius, but compared to Saturn’s usual -220 or so degrees, that’s pretty dang hot.

The rise in temperature was unexpected. A 20° rise is about the usual fare for these things, but then, this wasn’t a usual storm. Apparently, this hot spot started as two separate vortices, spawned by the storm seen in visible light, and moving around the planet at slightly different speeds. They eventually merged, forming this one ginormous vortex, which at its biggest was over 62,000 km (38,000 miles) across. Interestingly, it grew to this size around the time the visible storm had faded away.

Here’s a video from NASA’s Goddard Space Flight Center featuring planetary scientist Brigette Hesman describing the event:

Like any planet with an active atmosphere, storms on Saturn are common, but one this big had never been seen before. I’d say it was fortunate that we had a spacecraft like Cassini orbiting the planet when the storm erupted, but luck had very little to do with it: it was hard work and dedication that gave us that view. Cassini is such a well-crafted machine that it has operated nearly flawlessly for over eight years orbiting the distant planet. Its design and launch took decades to complete, and it took another seven years just to get to Saturn in the first place.

My point? Luck favors those who are prepared and have planned for rare circumstance. A storm like this one may not happen very often, but we were ready for it by having Cassini there in the first place, and by having a fleet of Earth-based telescopes with their eyes on the sky to support it.

… and having said that, I’ll note an irony: although it was right there, Cassini didn’t discover the storm in the first place. Why not? Because there’s just too damn much to see in the Saturn system! The storm erupted rapidly, and Cassini was busy looking at the rings and moons, so it missed the storm’s genesis. This is not a failure on the part of Cassini or its designers and users: instead, it should be seen as a clarion call for more spacecraft, more explorers in our solar system observing all the myriad worlds.

When I see images and science like this, I am filled with awe and joy, but I’m also struck with an implacable thought: what else are we missing?

Image credit: Leigh N. Fletcher, University of Oxford, UK, and ESO; NASA/JPL-Caltech/SSI


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CATEGORIZED UNDER: Astronomy, Pretty pictures, Top Post
MORE ABOUT: Cassini, Saturn, Storm, VLT

NuSTAR catches a black hole’s hot belch

By Phil Plait | October 23, 2012 1:33 pm

Our Milky Way galaxy is a sprawling collection of gas, dust, and hundreds of billions of stars, arrayed in a more-or-less flat disk. In the very center of the galaxy – just as in countless other large galaxies like ours – lies a hidden monster: a black hole. And not just any black hole, but one with four million times the Sun’s mass.

It’s called a supermassive black hole for a reason.

Usually, it’s not doing a whole lot except sitting there being black and holey. But sometimes it gets a little snack, and when it does it can let out a cosmic-sized belch. A very, very, very hot belch. Like it did in July 2012:

[Click to schwarzschildenate.]

These images were taken with NASA’s newest X-ray satellite, NuSTAR (more on that in a sec). NuSTAR can detect high-energy X-rays coming from space, and happened to be pointed toward the black hole when it erupted. On the left is an overview of the region near the center of our galaxy. The whitish area is the stuff immediately surrounding the black hole (the pink glow is most likely from a supernova, a star that exploded in centuries past). On the right is a series of three images showing that region getting very bright in X-rays, then fading away: a flare.

OK, so I know what you’re thinking. How can a black hole – famous for gobbling down everything nearby, even light – get bright and emit so much energy?

Basically, it doesn’t. The stuff around it does.

A black hole by itself is dark. But if a gas cloud gets near, very interesting things happen. The gravity from the black hole stretches out the cloud, because the part of the cloud nearer the hole gets pulled by the gravity harder than the part of the cloud farther away. Also, the cloud probably doesn’t just fall straight it; like an orbiting planet around the Sun it has some sideways motion. This means the hole whips it around, pulling out a long tendril which then spirals ever closer to the Point Of No Return.

This video may help. It shows a star getting torn apart by a black hole, but the principle is the same.

So some of the stuff may get flung away, but a lot of it falls toward the black hole. As it nears the hole, it forms a flat disk, called an accretion disk. The material in this disk is tortured by unbelievable forces: the inner part of the disk is whirling madly around the black hole, while the outer part is moving more slowly. The gas is literally heated up by friction as the different parts of the disk rub against each other (other forces like magnetism play a role too). The heating can be HUGE: the gas can reach temperatures of hundreds of millions of degrees!

Gas that hot emits X-rays, which is how this flare was seen by NuSTAR. Probably, a smallish cloud found itself too close to the black hole, got torn apart, and flew down into it. As it did it got extremely hot and blasted out X-rays. But when the whole thing was gobbled down, the X-rays stopped… because there was nothing left to emit them.

So maybe saying this was a belch is a bit misleading, since you do that after you eat something. This is more like your food screaming loudly and incoherently and flailing around while you’re actually eating it. Is that better?

This is a pretty cool observation. For one thing, our local big black hole is usually pretty quiet, so even getting a chance to see something like this is pretty nifty. Second, it can tell us what the environment is like near the black hole. And also, it helps us understand what happens right before some unfortunate object takes The Final Plunge. As I mentioned, every big galaxy has a supermassive black hole – ours is actually rather paltry compared to others; the one in the center of the Andromeda Galaxy is probably ten times more massive than ours – so anytime we can observe something going on with ours, we learn more about how they behave in other galaxies, too.

Also, I’m proud of NuSTAR. I worked on the project for a while, as part of the Education and Public Outreach team. I wrote quite a bit about the mission at the time, and was very pleased when it launched in June. It almost never got off the ground; the mission was actually canceled at one point, but was eventually reinstated.

I’m very glad it was! Now we can watch black holes in our galaxy (and others) as they eat and act rudely. Maybe it’s impolite to stare, but c’mon. When one puts on a fun show like this, it would be wrong not to.


Related Posts:

Astronomers see ANOTHER star ripped apart by a black hole! (including this original post and this followup)
NuSTAR opens its X-ray eye
The long reach of the Centaur’s dark heart
Desktop Project Part 22: A black hole belches out a hurricane

Flatly wrong global warming denial

By Phil Plait | October 23, 2012 10:24 am

Sometimes climate change deniers make it all too easy.

The UK paper Daily Mail has a long history of courting climate change denial, and apparently it has no wish to change. It recently posted an atrocious article called "Global warming stopped 16 years ago, reveals Met Office report quietly released… and here is the chart to prove it". The article was written by David Rose, who wrote a pretty inaccurate article earlier this year on a similar topic.

In fact, this new article was so blatantly wrong that the MET office – the national weather service for the UK – wrote a rebuttal to it detailing the flaws. To start with, they point out they did recently update their global temperature databases, but that’s a very different thing than "quietly releasing a report", as Rose claims. Cue the conspiracy music!

It gets worse from there. They take on his points one at a time and take them down. I highly recommend reading them. And if you haven’t gotten your fill of it, or you’re still not convinced, you can check out The Carbon Brief’s article that gives more details on Rose’s denial.

Or you can read the takedown by Skeptical Science.

Or by Open Mind. In fact, let’s take a closer look at that.

Tamino, the author of Open Mind, shows just how Rose picks and chooses his data to make it look like global warming stopped years ago. In the picture here, the top graph shows what Rose says the temperature looks like: flat across the past 15 years or so. But that’s terribly misleading: the starting point he chose falsely makes the graph look flat. The bottom one shows the true situation as Tamino describes it. You have to go farther into the past to find a reasonable starting point, and when you do, you see what looked flat is actually a rising temperature over time.

To do what Rose did in that upper graph is to strain reality (and credulity) past the breaking point. It’s almost as if Rose specifically chose the data that he liked and rejected the rest. That’s a big no-no in the reality-based world. Tamino thoroughly vaporizes Rose’s article, showing that it’s wrong in its most basic assumptions, its methodology, and its conclusions.

But other than that…

This article is just another in a long line of climate change denials that fiddles with the data to make it look like the Earth isn’t warming up. But it adds up. This kind of nonsense is damaging to real efforts to do something real about a real problem. And venues like the Daily Mail are all too happy to fan the fire while the world burns.


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From Here To Infinity

By Phil Plait | October 22, 2012 7:00 am

Looking up into the night sky, it seems like you can see forever. If you use binoculars or a telescope that feeling is, literally, magnified – you can see thousands, millions of stars.

But what you’re seeing is barely scratching the depths of the Universe. You’re looking out a few thousand light years into a galaxy a hundred thousand light years across, in a Universe where we can see distant galaxies over 10 billion light years away.

We build bigger telescopes so we can see those far-flung objects, and we even put them in space so our bothersome atmosphere doesn’t interfere with the view. The most famous is of course the Hubble Space Telescope. It’s hard to describe just how much of an impact this Grande Dame of astronomy has had on our perception of the Universe… though looking into the Hubble Deep Fields, you get a glimmer of it. In 1995, Hubble stared at one spot in space for over 140 hours, creating the first Deep Field. It revealed thousands of galaxies at tremendous distance, showing us that the sky is filled with galaxies.

The region of the sky for the first Deep Field was chosen because it was nearly devoid of stars and known galaxies, objects that would interfere with their more distant brethren. But what does that field look like from the ground? Astronomer Detlef Hartmann decided to tackle this question, and has done us all a favor by showing us. Using a 44 cm (17") telescope he built himself, he took an incredible 247 five-minute images to create this extraordinary picture with a total of 20 hours of exposure… and then lets it morph into the actual Hubble Deep Field to compare them:

[The image is an animated GIF that weighs in at nearly 6 Mb, so it may take a while to load. I urge patience; it’s worth it. Click to edwinenate.]

Holy. Wow.

Let me be clear: Detlef’s image is amazing. It’s a tremendous effort by an "amateur"*, and shows dozens of the galaxies (and the same scattered handful of stars) in the Hubble image. It’s an amazing achievement. A bigger telescope would show more galaxies, of course, and resolve them more clearly, but even the biggest telescope located on the surface of our planet needs to peer through the soup of air above it, which dims the faintest galaxies into obscurity. You need to get above our atmosphere to see the cosmos as clearly as possible.

And when you do, look at what Hubble shows us. That tiny region of the sky – easily blocked by a grain of sand held at arm’s length – contains thousands of galaxies, each a sprawling city of billions of stars. It represents a relatively random part of the sky, so you can expect to see something like it no matter where you point a telescope… and that picture shows just one 24-millionth of the entire sky.

The implication is clear: there are hundreds of billions of galaxies in our Universe. That in turn means there are sextillions of stars, each a Sun, and many, if not most, circled by a retinue of planets.

It’s the most ironic aspect of any science I know: it crushes my sense of scale and ego into dust, but also fills me with wonder and amazement that we can know such things, and be a part of it.

As is so often the case in science, you don’t know what you’ll get when you build a new instrument. You build it for one reason or for many, but later on new applications arise, new ways to use it. And sometimes, years down the road, it’s utilized in a just such a new way which profoundly changes how you see the Universe, how you see yourself and your place in it, and in a way you had may have only had an inkling of when you started out. The Hubble Deep Fields are perfect examples of this.

We knew intellectually the Universe was deep, and our place in it infinitesimal yet rare and beautiful. But Hubble showed that to us.

Image credits: R. Williams (STScI), the Hubble Deep Field Team and NASA; Detlef Hartmann. My deep thanks to Salvatore Iovene (who hosts AstroBin where Detlef’s image is displayed) for letting me know about this amazing work.


* Oh, that word. Detlef built his own ‘scope, took hundreds of these images, then combined them in a painstaking and difficult process that probably took him many, many hours. The word "amateur" has many connotations, but as usual here when I use it, I simply mean someone who is not a career astronomer. Detlef clearly has it going on.


Related Posts:

Revealing the Universe: the Hubble Extreme Deep Field
BAFact Math: The Sun is mind-crushingly brighter than the faintest object ever seen. Seriously.
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Hubble digs deep to see baby galaxies

ALPHA CENTAURI HAS A PLANET!

By Phil Plait | October 16, 2012 4:45 pm

Huge news! Astronomers have announced they have found a planet orbiting one of the stars making up the most famous star in the sky: Alpha Centauri, the closest star system to our own! At 4.3 light years distant, this is far and away the closest exoplanet known… and of course, it has to be.

Alpha Centauri is a triple-star system, composed of a binary star, two stars much like the Sun – one slightly larger and hotter, called Alpha Centauri A, and the other slightly smaller and cooler, called Alpha Centauri B – orbited themselves by a red dwarf (called Proxima Centauri) much farther out.

The planet orbits close in to Alpha Cen B, and is technically called Alpha Centauri Bb – planets have lower case letters assigned to them, starting at b. Its mass is only 1.13 times the Earth’s mass, making this one of the lower mass planets yet found! But don’t get your hopes up of visiting it – its period is only 3.24 days, meaning it must be only about 6 million kilometers (less than 4 million miles) from its star. Even though Alpha Cen B is a bit cooler than the Sun, this still means the planet is baking hot, far too hot to sustain any kind of life as we know it, or even liquid water.

Still. Holy crap! A planet for Alpha Cen. Wow.

The reason this is a big deal is twofold. For one, Alpha Cen is the closest star system in the sky. Because of that it’s very bright, and well studied. Planets searches have looked there for decades, and in fact for a while it was thought the dinky red dwarf Proxima might have a planet. Those earlier findings have been shown to be wrong, though. If it has a planet, it’s too small or too far out from the star (or both) to detect it easily.

The other reason this is important is that the signal from the planet is incredibly weak. It was found through its gravity. As it orbits Alpha Cen B, the planet tugs on the star, like two children holding hands and swinging each other around. This sets up a very small but detectable Doppler shift in the starlight. The more massive the planet is, the harder it tugs on the star, and the bigger the signal (making it easier to detect). Also, the closer in a planet is, the larger the signal is… and you get the added benefit of a short orbital period, so you don’t have to observe as long to see the cycle of the Doppler shift.

In this case, the planet is low mass but very close in. The Doppler shift in the starlight amounts to a mere half meter per second – slower than walking speed! When I read that I was stunned; that low of a signal is incredibly hard to detect. Heck, the star’s rotation is three times that big. But looking at the paper, it’s pretty convincing. They did a fantastic job teasing that out of the noise.

The graph displayed shows the effect of the planet on the star. RV means "radial velocity", the speed toward and away from us as the star gets tugged by the planet. The x-axis is time, measured in units of the period of the planet (in other words, where it reads as 1 that means 3.24 days). The dots look like they’re just scattered around, but when you average them together – say, taking all the dots in a one hour time period – you get the red dots shown (the vertical lines are the error bars). The signal then pops right out, and you can see the tell-tale sine wave of a planet pulling its star.

Amazing.

This is incredibly exciting to me! A few years ago, when I worked on Hubble, I looked into using it to search for planets around Alpha Cen. I worked out some simulations to see if we could detect anything, and at best we could see a Jupiter-sized planet orbiting far enough out that its faint light wouldn’t be blasted out by the star itself. It was deemed too risky an observation (too low a chance of payoff) so we didn’t get time on the telescope to make it. We’d never have seen this planet anyway; looking for a planet reflecting its star’s light is very different than looking for the Doppler shift. Obviously!

Also, c’mon. This is Alpha Centauri! Famed and fabled in a thousand science fiction stories. It’s where the Robinson family was supposed to go in "Lost in Space". It’s where Zefram Cochrane lived in "Star Trek". It’s where the Fithp came from in Footfall. Because the system is bright and close, and the stars so close to being like our own Sun, they’re an obvious place to put aliens. Plus, you get the exotic locale of a binary star plus the red dwarf thrown in on top. It’s perfect!

So I, and a lot of people like me, grew up hoping against hope we’d find a planet around one of these stars someday.

And here we are.

My very, very sincere and gracious thanks to the team that made these observations. Even if this planet is cooked to within an inch of its life, this is still literally a fantasy come true.

And it reinforces my own thinking that we are very close to finding a planet with the same mass as Earth at just the right distance from its star to have liquid water, and therefore, potentially life. We are finding planets the right mass but at the wrong place, and at the right place but with the wrong mass.

But we’re zeroing in on Terra Nova, folks, and statistically speaking there should be millions of them in the galaxy. It’s only a matter of time before we find the first one.

Image credits: ESO/L. Calçada; ESO/Digitized Sky Survey 2 (Davide De Martin)


Related Posts:

Exoplanet in a triple star system smack dab in the habitable zone
A nearby star may have more planets than we do!
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Theoretically, Alpha Centauri should have planets

CATEGORIZED UNDER: Astronomy, Pretty pictures, Top Post

Space Leap of Faith

By Phil Plait | October 16, 2012 11:44 am

On Sunday, skydiver Felix Baumgartner stepped out of a high-altitude balloon and plummeted 40 kilometers back to Earth. I wanted to watch it live but missed it due to an appointment I had to keep. I heard it was heart-pounding, and Twitter went nuts over it. I wish I had seen it!

Still, my feelings on it are mixed. While I really am glad it got people excited, I couldn’t shake the feeling it wasn’t more than a stunt. A cool stunt, but a stunt. It was plugged as a way to learn more about spacesuits and all that, but I had my doubts. Having it sponsored by a sugary caffeinated energy drink marketed to teens also made me a bit wary.

I was thinking of writing something up about it, but then my friend and space historian Amy Shira Teitel wrote an excellent piece crystallizing my thoughts, so go read her article for more in that vein (which is also mirrored on Discover Magazine’s blog The Crux).

But what I really wanted to write about was this image I saw around Twitter and Facebook:

Why do I want to write about this? Because, in a nutshell, it’s everything wrong about attitudes on our space program. If I sound a little peeved, I am. Here’s why.

This meme was started in a tweet by revulv. I suspect it was just a joke, and to be honest it’s funny enough; I smirked when I read it. But someone took that joke and added the picture, and then it got spread around. And I can tell by the comments I’m seeing people really think it’s true – this idea has been around since the Shuttle retired, and it’s unfair. It’s simply not true.

First, as Amy points out in her post, Baumgartner’s jump was a record breaker, but he wasn’t in space. Our atmosphere thins out with height, and doesn’t really have an edge where air ends and vacuum begins. Because of this, there’s an arbitrarily agreed-upon height where we say space "starts" – it’s called the Kármán line, and it’s 100 km (62 miles) above sea level. Baumgartner was less than half that high. When I talked about his jump I used the phrase "edge of space", which is probably fair. He was in a pretty good vacuum by ground standards, but in space itself he was not.

Second, he wasn’t in orbit. A lot of folks confuse being in orbit and being in space, which is understandable. When we say something is in space that means it’s just higher than that arbitrary limit. You can get there via rocket by going straight up 100 km and then back down, for example. That’s a suborbital flight.

But being in orbit is different. An orbit is where you are free-falling around the Earth. Think of it this way: in orbit the Earth is pulling you down to the surface, but you’re going fast enough sideways that you never actually hit (to paraphrase Douglas Adams: orbiting is learning how to throw yourself at the ground and miss). Your velocity down and your velocity to the side add together to give you a circular (or elliptical) path.

Baumgartner used a balloon to go straight up. He wasn’t in orbit.

And that’s two of the three things that bother me about that meme picture: he wasn’t in space, and he wasn’t in orbit, two things the US has rockets that can do.

Now, some people will point out that in fact the US cannot do that, at least not with people. We don’t have any rockets rated for human flight into space.

That’s true, but brings up my third point, the most important, what a lot of people don’t seem to get: you need to add the words "right now" to the end of that sentence.

We can’t launch humans into space right now. But in just a few years we’ll have that ability. In spades.

SpaceX is working on making sure their Falcon 9 rocket is human-rated for flight – even as I write these words they have a Dragon capsule berthed to the International Space Station. ATK is another. There’s also Sierra Nevada, Blue Origin (which just had a successful engine firing test), XCORR, and others. Let’s not forget Virgin Galactic, too. [Update: D’oh! Shame on me, and ironic too: I forgot to add Boeing and ULA’s work on this as well.]

Both SpaceX and ATK think they’ll be ready to take people into orbit in 2015. Virgin Galactic and XCORR may be ready to do commercial suborbital flights before that date. [Note added after posting: I want to be clear; these are not NASA programs, but some have contracts with NASA, and I’m talking about the US as a nation, not necessarily as a government space program.]

The Space Shuttle was retired in 2011. We’re in the middle of what’s planned to be a five year gap where the US can’t take humans into space. Mind you, when the Apollo program shut down there was a nine year gap before we had a program to take humans to space again (with the exception of a few Saturn flights to orbit for Skylab and the Apollo-Soyuz mission; even then there was a six year gap until the Shuttle launches began).

My point? Things aren’t nearly as bad as people think. Yes, the Shuttle is retired, but to be brutally honest, while it’s an amazing machine, it could not nor would it ever be capable of taking humans beyond low-Earth orbit. It also cost way more than promised, and couldn’t launch as often as promised. I’ve made this point before, and it’s one we need to remember. Getting to space is not easy, and if we want to do it we have to do it right.

And let’s not forget we are still throwing rovers at Mars, probes at Jupiter, and one satellite after another into Earth orbit. We’re still going into space, if by proxy. Humans won’t have to wait much longer.

We need to learn from the past and keep our eyes on the future. By looking at the past we can see by comparison things are not so bad right now; we’re just in a lull before the storm. We’ll soon have not just the capability to put humans in space, but many capabilities to do it! Space travel will be easier and cheaper than it ever has been since the dawn of the Space Age.

My goal is to see nothing less than the permanent colonization of space by human beings, and I strongly suspect we are not that far from achieving it.

Image credits: Baumgartner pic via Red Bull; orbit diagram via Wikimedia Commons.


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Amateur planet hunters find a world with a four star rating

By Phil Plait | October 15, 2012 9:30 am

A new exoplanet – a planet outside our own solar system – has been found, and it’s pretty cool for two reasons: it was found by amateur planet hunters, and it’s in a four-star system!

OK, first, the planet: called PH-1, it’s bigger than Earth, about six times our radius, or about half the diameter of Jupiter. The mass isn’t well known, but may be as high as 170 times our own mass, though far more likely it’s closer to 20 – 50 times our mass. That makes it closer physically to Uranus and Saturn than Earth, so it’s likely a gas giant. It’s also hot, with a probable cloud-top temperature of 400+ Celsius (800+° F). Even if it has Earth-sized moons they’re likely to be too hot to be hospitable. And since it’s 5000 light years away, we’re not headed there any time soon, anyway.

But the more interesting thing about this planet is its host stars: PJK-1 orbits a binary star, two stars that orbit each other (like Tatooine, if you like). Six other planets are known to orbit binary stars, but PH-1 is even cooler: the binary star is itself orbited by another binary pair much farther out, making it the first planet found in a four-star system.

So we have two stars orbiting each other, orbited by a planet, and also orbited by two other stars which orbit each other. Yegads.

But it gets better yet. This planet was not found by professional astronomers! It was discovered by two amateurs who participate in the Planet Hunters program. This project was started by astronomers using the orbiting Kepler Observatory, designed to stare at 100,000 stars and look for dips in light from them as any potential planets orbiting them block their light. These transits show up in graphs of the stars’ brightnesses, and actually our human eyes and brain are pretty good at picking them out. Planet Hunters puts Kepler data online for anyone to go in and poke around.

The two citizen scientists, Kian Jek and Robert Gagliano, are listed as authors on the scientific paper recently published. I love this: the digital nature of these data make it far, far easier to analyze the science than it was in the past, and also easier to get the data out to people. Because of this, we have an explosive growth in these kinds of projects. Planet Hunters is great, but then so is Galaxy Zoo, Moon Mappers, Ice Hunters, and so many others. You can find several of these collected at the CosmoQuest website.

And a word about this new planet; this isn’t the first planet found by Planet Hunters, but it’s the first ever found in a quaternary star system. In the image here, the central binary is the big blob in the middle, and the second pair the elongated double-blob to the lower left. The planet is far too close to the middle stars to be seen here – its orbit is smaller than Earth’s around the Sun, far smaller than a pixel in this image at that distance.

The central binary is made up of a bluish star hotter and brighter than the Sun, and one that’s cooler, fainter, and redder. The second binary is made of one star much like the Sun, and another dinky red one. Their distance from the planet – about 150 billion kilometers – means they’d both still be very bright, with the brighter of the two almost as bright as the full Moon as seen from Earth. What a sight that would be! The second star would be hard to pick out in the glare of the other, but with binoculars you could spot it.

Not that anyone could, since the planet is hot enough to melt tin and assuming it had a solid surface to start with. Still though, it’s not hard to imagine a smaller planet orbiting that binary farther out, in a cooler, more life-friendly position. And we know such a planet exists; Kepler recently revealed a planet orbiting a binary star at the right spot to have liquid water as well. Like PH-1, that planet is probably a gas giant, but it might have big moons…

And this shows us once again that nature just loves to make planets, even ones in really weird places that at first may seem inhospitable for planet formation. But there it is.

Every time we find a strange planet like this, it fills me with hope that the ultimate goal of this work is close: finding an Earth-sized planet in the habitable zone of another star. We’re getting closer every day to that announcement, I think. In fact, I strongly suspect that planet is already sitting in the Kepler data, faint and hard to tease out, but just waiting to be found.

Go sign up for Planet Hunters. Maybe you’ll be the one to find it.

Image credits: Haven Giguere/Yale; Keck Observatory/Megan E. Schwamb et al.


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A butterfly in the Swan

By Phil Plait | September 21, 2012 7:00 am

I am constantly amazed and awed by the sheer beauty of planetary nebulae – the gorgeous structures created as stars die.

Among the most astonishing of them is NGC 7026, a youngish nebula about 6000 light years away in the constellation Cygnus, the Swan. Here’s a stunningly beautiful picture of it from the Hubble Space Telescope:

[Click to enlepidopterate.]

Planetary nebulae (or PNe for short) like this are sometimes called "butterfly nebulae" because of their shape. It’s easy to see why; there are two big lobes that are roughly shaped like butterfly wings. The history of those lobes is complex.

You can see the central star, right in the middle. That used to be a star much like the Sun, though more massive and hotter. As it ran out of fuel in its core, it swelled up to become a red giant. It started to blow a slow, dense wind of gas, like the solar wind but much thicker. This expanded into space around it. Eventually, the star blew off so much of its outer layers that the hotter lower layers were exposed. This causes the wind to speed up substantially and get much thinner. The fast wind catches up with and collides into the slower, older wind, carving all manners of weird shapes.

The overall shape of the nebula depends a lot on two things: material outside the star into which the winds are flowing, and what shape the winds themselves are.

You might think the winds would expand in a sphere, but there are forces that can change that. If the central star is a binary, for example, centrifugal force can cause the slow wind to be flattened, like someone sitting on a beach ball. It’s thicker along the equator as it expands. When the fast wind slams into it, it get slowed a lot by this thicker waist, but the thinner gas along the poles means the fast wind can plow on through. What finally happens is the formation of a double-lobed structure like a bowling pin with a ring around the middle… just like NGC 7026! The ring around the middle isn’t obvious in this picture, but you can see how the pinched waist is brighter, which is a tell-tale sign of a ring (similar to how some nebulae look like smoke rings).

That explains the gross structure. But look at all the detail! Those fingers of stuff pointing inward toward the middle, the complex lobe structure? What gives there?

The clue comes from the location: Cygnus the Swan is a part of the sky where we’re looking into the plane of our flat Milky Way galaxy’s disk. That means there’s more gas and dust there than usual, and NGC 7026 is in the thick of it. The lobes of gas from the star are slamming into all that junk, creating these weird patterns. Those fingers are very common when hot, fast gas flows past denser, cooler gas (it’s called a Rayleigh-Taylor instability, if you want details).

I strongly suspect that explains the butterfly-shaped structure as well. The junk surrounding the nebula is not smooth, and is denser in some places in others. Where there’s less material, the winds from the star can poke through more easily and expand. If you’ve ever blown up a balloon with a weak spot in it you get the same thing. It’s essentially a hernia!

I read a couple of research papers about NGC 7026, and this idea does seem to fit with what’s observed. The lobes are also filled with very hot gas that emits X-rays, and that also makes sense if the lobes are still plowing into surrounding material; the hot gas hasn’t been able to escape because the lobes are closed.

Which means one more thing: eventually all that material may blow out of that cloud, popping it. When it does – in what’s called a "blowout" – the gas will escape and it’ll probably form long, weird, filaments like a shredded balloon. And that means, if it’s even possible, this object will become even more interesting, and even more beautiful.

Image credit: ESA/Hubble & NASA


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Chaos! Turbulence! Blowouts! Herschel!
Cas A blowout

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