Slashdot Mirror

revealingheart writes with this quote from ScienceDaily: "On 5 and 6 June this year, millions of people around the world will be able to see Venus pass across the face of the Sun in what will be a once-in-a-lifetime experience. It will take Venus about six hours to complete its transit, appearing as a small black dot on the Sun's surface, in an event that will not happen again until 2117. ...Transits of Venus occur only on the very rare occasions when Venus and Earth are in a line with the Sun. At other times Venus passes below or above the Sun because the two orbits are at a slight angle to each other. Transits occur in pairs separated by eight years, with the gap between pairs of transits alternating between 105.5 and 121.5 years — the last transit was in 2004." You can check this chart to see whether it'll be visible at your location, and when you should look. You'll need a safe way to watch unless you are Vulcan. And yes, there's even a phone app to help you out.

You asked Phil Plait, aka The Bad Astronomer, questions on topics ranging from debunking superstition to extraterrestrial life to funding space exploration; read on below for his answers. Thanks for taking part, Phil! My galaxy is bigger than yours?
fuego451

In January of '09, The BBC ran a story on research done by scientists at the Harvard-Smithsonian Center for Astrophysics. Using the VLBA they found what they felt was very good evidence that our galaxy is about the same size as Andromeda (150k ly). However, very few of their fellow astronomers, including you, are touting this new size. Why? Was the study flawed?

From reading the story, the study looks legit; it's using techniques that have been around a long time and are well-understood. The reason I didn't write about it is because I didn't know about it! Well that's one reason. I get a bazillion press releases, and I can't write about all of them; I physically can't — that pesky only 24 hours in a day thing — and I've found that if I write too many in-depth astronomy posts every day, my traffic actually drops. Weird, isn't it? But true, so I pick which ones interest me the most and write about those.

In this case, too, I see a story every few months claiming we're bigger than M31, then another saying M31 is bigger than us. Even if each study is done perfectly, and turns out to be right, I can't write about them every time. It's overload on the reader, and it becomes an issue of everyone saying, "Wait, which way was it last time?" Incremental stories are very tough to write, especially in a series. It's like when astronomers find the lowest mass planet yet, and really it's just barely lower mass (within the error bars) of the last one. It's interesting, but unless it really blasts through the last record and brings us into new territory, it's ultimately just a footnote. Cool, and important, but if I wrote about every one I wouldn't have nearly enough time to watch TV and moon over River Song.

Extra Solar Planetary Imaging
mklopez

I just had an interesting argument with a coworker. The point: while he can accept that space-based telescopes would be able to do direct imaging of extra solar planets — assuming that they can directly capture the photons traveling across all the involved light-years without interference — he just doesn't believe that is possible to image those planets from the Earth surface, given atmospheric interference. He says that the images from Hawaii and other Earth observatories are just software interpolations that try to "guess" and "process" (his words) the anomalies in the images as planets... in other words, they are unintentionally "photoshopped" (again, his word). The basic question would be, then: how can a telescope inside our atmosphere be able to "take pictures" of something as faint as extrasolar planets?

Well, to be clear, your friend is wrong. :) The images taken using Keck, Gemini, the VLT and others are just as legit as the ones from Hubble (I have a gallery of them here.) The Earth's air does mess up images pretty well, since it's turbulent and fuzzes out light coming down. But there are several techniques that are used that are physically and actually compensating for that motion, including adaptive optics and laser guide stars. This isn't some sort of interpolation or picking out blips, it's literally measuring how much the atmosphere is distorting things and compensating for it. In some cases, over small areas of the sky, these techniques allow for higher resolution imagery than Hubble can produce!

Seeing faint planets near stars is really hard; if it were easy, we would've been doing it a century ago. But this new tech is pretty good at what it does. It's not magic, it's science.

Space junk
dcsmith

How serious is the amount of 'space junk' orbiting Earth? Will it have a substantial impact on the future of space flight, manned or otherwise? What are some of the best (or at least most innovative) ideas you've heard about for deorbiting big junk or cleaning up smaller bits of debris?

Well, NASA sure takes it seriously. The space station has had to boost itself to different orbits several times to make sure it got out of the way of some bit of debris or another. NASA has an entire office devoted to looking at debris and tracking it (http://orbitaldebris.jsc.nasa.gov/) and the National Reconnaissance Office does as well. Everything bigger than the size of a tennis ball in orbit is tracked, and there are thousands of them. At orbital speeds, a fleck of paint can put a hole in a spacesuit — it can have the same energy of impact as a bullet!

Big stuff is trackable, so while it's dangerous at least you can do the math and get some advance notice of a potential impact. The tiny stuff is far more dangerous, because you don't know where it all is — and also because there's lots more smaller stuff than bigger stuff (take a hammer, smash a rock, and them look at how many big pieces you get versus tiny ones).

One idea I thought was cool to get rid of debris is to hit it with a laser, heating it up and boiling off material. That acts like a wee rocket, pushing the debris into orbits which allow them to decay faster. Pretty cool, and possible though difficult in a practical sense. There's a *lot* of stuff up there. One thing is for sure; we need several different strategies to get rid of this stuff. There's no one panacea for it.

Naked eye astronomy
rickett81

I enjoy gazing at the heavens sometimes but by no means would call myself an astronomer. Short of purchasing a telescope and driving out of the city, do you have any suggestions for 'naked eye' astronomy in an area of moderate light pollution?

Yeah! There are approximate a bajillion sites that can predict satellite passes for a given location; I always use Heavens Above. Random satellite passes are fun, but seeing something like the space station or Hubble is very cool. Iridium flares — bright flashes off of reflective surfaces on Iridium commsats — are really nifty to see. And many get bright enough to spot even from places where light pollution is a problem.

There's also meteor showers, of course. But my best recommendation to everyone is to get a pair of inexpensive but solid binoculars. You can see Jupiter's moons, craters on our own Moon, Saturn's rings, and more. And they're always good to have around if you hike or just see a bird or something in the distance. I always have a pair handy. Always.

Where to start helping?
modi123

Way back when I was a freshman in college I was considering a carrier in astronomy and physics, but I opted for the more flashy and showy job of application development. Is there room for hobby astronomers to contribute in a meaningful way to the global community, or should I stick with the crowd-sourcing projects on zooniverse.org?

Well first, those citizen science projects are freaking fantastic. They're producing all kinds of interesting science. Zooniverse is a good place to start.

It used to be that comets and asteroids were all discovered by amateurs, but robotic telescopes rule the night now. Still, "amateur" observations play a big role; that big storm on Saturn last year was discovered by an amateur, as were several asteroid/comet impacts on Jupiter. Those are rare events, of course, and discovered because there are lots of amateurs looking at the sky. Realistically, any specific person's odds of contributing that way are small, but overall the combined probability approaches 1. :)

But those online citizen science projects are only getting bigger, and more are on the way. It's a fun way to do real science, and make a difference.

And we do need more and better astronomy app, so maybe you chose the right career after all.

Viewing the Transit of Venus Next June
nani popoki

Next June, I plan to travel from Boston to Hawaii (probably Kauai) to view the transit of Venus. I can take a small (90mm mak cas) telescope and a solar filter, but trying to cope with airline carry-on luggage restrictions and get a 4" diameter, 10" long aluminum cylinder through airport security is going to be a pain. Can viewing the transit be done using a camera obscura technique like one might use for viewing a partial solar eclipse?

For those wondering, a transit of Venus is when the planet passes directly in front of the Sun as seen from Earth; the next one is in June 2012, and there won't be another until 2117 (weirdly, due to orbital math, they come in pairs each separated by 8 years, but then the next pair coming over a century later). So this is your chance. TransitofVenus.org has tons of info. I saw the last one in 2004, and it was awesome. All I used were special glasses that blocked sunlight; Venus was visible as a tiny dot on the Sun's face.

Getting a telescope through security is risky; they could damage it, or it could be stolen, or they could decide it's a weapon, and then parts of *you* might get transited that you would prefer remain unocculted. You could ship the 'scope through the mail in advance, which is probably safe enough. You could also just use binoculars to project the Sun's image on a piece of paper; this is great for viewing, but difficult to photograph. Still, probably better than a pinhole camera or camera obscura.

Threats from Space?
north.coaster

We're always hearing about threats to our planet from outer space. Asteroid impacts Gamma Ray bursts. Invaders from Mars. The list goes on. What do you think is our biggest threat from space, and why?

We're all gonna DIEEEE AIIIIEEEE!!!

OK, with that out of the way... it depends. You have to weigh severity with chance. So, a GRB can sterilize the Earth in ten seconds flat, but the odds of one happening in your lifetime are millions to one against (and we don't have any good GRB candidates close enough to do the trick anyway). The Sun will expand into a red giant and fry the planet for real and for sure... but not for 5 billion years. So lots of big disasters aren't much to fret over.

My two biggest concerns are asteroid/comet impacts, and solar storms. A blast from the Sun can't really hurt us directly, but it can really mess up satellites, and a lot of our navigation and economy depends on them. Also, they can cause big blackouts over large areas (like Quebec had in March 1989), and that's pretty serious. We can take measures to prevent this (hardening our satellites against storms, and adding more power capacity to the grid to handle overloads) but that's expensive, difficult, and hard to convince company CEOs of the threat. With the solar peak coming in 2013/2014, we'll just have to see what happens.

Asteroids and comets are probably the biggest threat. We *know* no dinosaur killer is on its way here for at least a century or three, so that's cool. But the Tunguska event in 1908 (a 20 megaton explosion) and the Meteor Crater impact (in Arizona, also about 15 — 20 MT) were caused by rocks only about 50 meters across at most, and we wouldn't see one of those coming in until it was practically in our atmosphere. Literally.

But there are people taking this seriously (like the B612 Foundation). We're looking for killer rocks, and there are ideas of ways to push them away from us. I gave a TEDxBoulder talk on this, with details: It's only 12 minutes, and should scare you and then mollify you.

A couple of questions on NEOs
hairyfeet

I'm strictly a layman sky gazer so apologies if I don't use the right terminology. 1. What would you say our risk level for NEOs is? I know we make fun of the Naburu or whatever that crazy rogue planet thing is called but last I heard we had only mapped about 2% of the sky and with all that space it does make me wonder if we would actually see a NEO that was a danger before it was too late to do anything, and as a follow up 2. If we were to spot a NEO that was a danger do you believe we could divert it with our current technology, if so how so? Gravity tractor, using nukes as shockwaves to divert, maybe solar sails? How far away would the NEO have to be detected at for these to work?

I already talked about dangers from NEOs in the answer above, so there you go. The mapping question is a good one, but you have to be careful. For example, we know there is no Nibiru because if there were its gravity would have affected the orbits of other planets. Also, a planet as big or bigger than Jupiter would be naked eye visible for decades (centuries, really) before getting here. So in that case we don't need to map the whole sky.

Same thing, kinda, with asteroids. We have mapped so many now that the odds of one as big as the dinosaur killer coming in the next few centuries is really small. Smaller ones really are hard to find though. The good news is we're getting better at it, and more telescopes are coming that will map the sky more and more.

If we do see one, the best course of action depends on how big it is, and how much time we have. If time is short before impact (like
Fermi question
JoshuaZ

What do you think is the answer to Fermi's question? That is, why do you think we see no signs of intelligent life other than humans?

I don't know what the answer is. I mean, duh, no one does. The idea that we're first is not so slanderous to me, but the problem with it is the timescale. Planets like Earth could have easily formed a billion years earlier than Earth, and that's a helluva long time. Even with slower-than-light ships you can colonize the entire galaxy in just a few million years, a fraction of a billion years. So that bugs me.

We know there are lots of Sun-like stars out there (billions of 'em) and Earth-like planets are looking like they're pretty common too, given what we're learning. So it may boil down to how easy it is for life to arise (which I think is pretty easy)... but also on alien psychology. Of all the factors in the Drake equation, I suspect that's the one that we'll never know until we meet aliens. Maybe they won't care about exploration and contact. Maybe they are so weird we can't even guess what's going on.

So, short answer: beats me. We should keep looking.

Light pollution
Frenzied Apathy

There are a large number of light pollution articles to be found on the Sky and Telescope website. We amateur astronomers are keenly aware that light pollution isn't just about being able to see more stars from our backyard. Yet, when I mention the subject to friends, family, co-workers, etc, I often get a blank stare. "What's 'light pollution'?" What do you think can/should be done to improve widespread public awareness of light pollution and its effects?

That's a tough one. I've written about it a few times, but it doesn't reach the right people. Public advocacy works; I know some towns have changed lighting to reduce light pollution. That's still small scale though. The best way is to drag people out to dark sites; my wife and I were recently in the mountains at night and she was shocked at how many stars she could see. That may not be a practical way to change lots of minds, though! So honestly, I don't know. I wish I did. Usually, switching to more efficient lights that are also not polluting the sky save money, too, but that does seem to be a hard sell. If someone has a solution, let me know!

Pie in the Sky
Colonel Korn

If you could give Apollo-level funding to a single NASA program, what would it be? Would you direct that money internally or involve private space companies?

I don't think that's the right way to ask that question. NASA does a LOT of stuff, a lot of it very cool. Some of it could be better directed, I think. I'm not so sure I see the need for a heavy lift rocket from NASA, for example, when private companies are well on their way to making those. I prefer NASA innovate, rather than do stuff others can do.

So what I'd like to see is to have their budget doubled. Boom! Just like that. That, plus heavy lift capability from private industry, and there's no more worrying over scraping a gram or two off a Mars probe; you make it as big as you want, and if something doesn't fit, you build another one and launch it later. It's not that the money isn't there — we spend 10+ million bucks *an hour* in Iraq and Afghanistan — it's that we don't choose to do it.

Finally, what do you think of lunar-based observatories from a cost vs. performance standpoint?

I like the idea of a radio telescope on the far side, blocked from Earth's interference. But I'm not sold on optical lunar scopes. Putting them in orbit around Earth is way cheaper, and you don't have to worry about lunar dust, or gravity warping your optics, and a hundred other issues.

If, someday, we have a lunar colony, then yeah! There are plenty of native materials that can be used to build 'scopes. Until then though, space-based is the way.

Mars, Europa, Enceladus or Titan?
wisebabo

Is this like MFK?

If you had to choose a major (Discovery?) class probe to look for life beyond earth which celestial body would you send it to?

• Mars (methane outgassing?)
• Europa (subsurface ocean?)
• Enceladus (water "fountains"?)
• Titan (liquid water, ammonium, hydrocarbon ocean?

Oh. Well, as a scientist, Mars, which has so much cool stuff going on — it's a freaking *planet* — that there're endless things to learn. As a human and scifi fan, Europa. The scientific payoff is arguably less than Mars, but the idea of exploring an undersurface ocean is awfully tempting. And it's a lot closer than Saturn. I think it and Enceladus are tied for interest, but Europa is a lot easier to get to. I'd like to see a dedicated Titan probe eventually, but since we don't have unlimited funds, I think it's smarter to go with a safer bet. We don't *know* life can arise in lakes of liquid methane, but we do know it can in water. So overall: Europa.

Are you familiar with Peter Ward's book "Life but not as we know it" in which he makes a strong case for Titan? Do you agree?

I haven't read it. But life on Titan, but in the end, is still speculation, no matter how solidly it's based in known science. That's true for Europa too, of course but the speculation is less extended, since we know there's liquid water there. So I think I'd rather see a probe go to someplace where we know the circumstances for life are good.

Funding for small, interdisciplinary projects?
LeDopore

I've noticed a disturbing trend that as funding levels drop, agencies are receding more to their core areas of study and leaving interdisciplinary scientists high and dry. Furthermore, it seems that there's an inverse relationship between the fund-ability of a project and its efficiency: if a (say) particle physics project is so inefficient it requires 1000 scientists 10 years to get 1 bit of data (like the Top quark discovery) then they're guaranteed to have well-coordinated funding and lobbying effort, whereas projects that deliver results on only a shoestring budget might not have enough people working on them to get any funding at all.

I'm working at the interface between neuroscience and algorithm theory, and I've already made some very interesting discoveries using borrowed time/funding, but I have trouble shopping my ideas to either pure neuroscience/medical funding agencies (who don't understand the math) or to computer science funding agencies (who don't appreciate the biology). Both sides seem generally excited and encouraging, but neither is willing to fund my future research, since (despite a promising track record) I'm out of the expertise of anyone out there.

My question is, are we doomed to a future dominated by big science projects working in entrenched specialties on the least-efficient, longest-term, too-big-to-fail science investigations out there? If not, how do we promote efficient, small-scale, interdisciplinary project funding?

I'm no expert in this, but I have to wonder if the 'net is changing that. The example is TV shows. It used to take a vast budget, a huge staff, and all kinds of expertise to make a show, and it still might be crap. :) Now, people can do it for not much money at all, and lots of stuff on the web is pretty damn good! And it's egalitarian in many cases, with the best stuff rising up.

Science may be the same way. Small projects can get funded through microdonations — Kelly Weinersmith is doing this, and raising funds for her research into parasites, for example (http://www.weinersmith.com/?p=483). Citizen science projects are popping up all over the place. It's a funny time right now, with things in transition, but I suspect it'll solidify in the next few years.

Funding for the JWST?
wisebabo

Do you support finishing the JWST, which is now substantially behind schedule and over budget? (I realize that many of the problems were caused by Congress but unfortunately that's where we are today). What about if a substantial amount of the money needed to complete it is taken out of other astronomy related programs?

I'm torn about this. I supported JWST up until recent revelations that it would cost more than even NASA's overestimates. Cost overruns may have to come out of other NASA missions, and that's *NOT* acceptable. The House wants to kill it, but the Senate wants to fund it, but they still haven't said where the money will come from! It's a mess.

Canceling it outright would be a mistake, I think, since it's the only big astrophysics project NASA has going right now, and it'll keep a lot of astronomers employed for a long time. :) But of course it will revolutionize science the way Hubble did — which was also hugely over budget, behind schedule, and a political nightmare, BTW. Yet that's not how people think of Hubble now at all.

So I honestly don't know what to do. maybe we'll get a better idea once the Senate and House hammer out their two different budgets. But given the atmosphere in Congress, I wouldn't make bets either way.

Dangerous Bad Astronomy
BeardedChimp

In science a simple misconception can lead to thousands and millions of people being skeptical and disbelieving. For example the large number of people who think that humans evolved from chimpanzees rather than sharing a common ancestor. In astronomy, what misconception would you class as most dangerous to the general public's understanding?

I don't think there's any one misconception that's most dangerous, but I might say that the idea that there are mysterious things out here poised to kill us that the government is covering up might be most pernicious. Lots of people — kids mostly, but not all — are terrified over 2012, and think some giant planet or solar flare will kill us all. That makes me so angry I want to kick puppies [Note: that's a metaphor. Puppies do not make up fake doomsday scenarios in order to bilk people out of money and scare them half to death.]. Not that people are wrong in this belief — ignorance is curable — but that so many people spread this idea to sell books. 2012 is 100% unadulterated pure crap, with absolutely no basis at all. None. Yet I get emails from people who are scared out of their minds over it.

At the risk of oversimplifying, it comes from a lack of scientific thinking, lack of skeptical training, and the atmosphere of governmental mistrust. If we as a people had a better grasp of science and the process behind it, a lot of this garbage would evaporate. But this is the price we pay for not supporting science education more.

Trends in misconceptions?
vlm

Do you see long term trends in various misconceptions? It seems subjectively to me that the "vernal equinox egg" deal was way more popular in the '80s. Its a random variable on the timescale of a couple years.

The only trend I see is overall permanence. :) Things come and go, but there are always *things*.

The egg myth does seem to be dying, and I'm more than happy to take full credit for that. :) But other stuff comes in and fills the vacuum.

Other misconceptions, like "the far side of the moon is always dark" or "the moon always rises at sunset and sets at sunrise" have a relatively constant rate of mis-belief over time. Another type of misconception is the flash in the pan like the "face on Mars" which gets intense media attention for awhile and then fades (permanently?) into obscurity. Do you see any general trends in the distribution of the three types of misconceptions over time, like one getting more or less popular or ... maybe due to social media or something?

Some of these idea stick around because of inertia or a lack of proper debunking (like the Moon being bigger on the horizon; that one has a hatfull of bad explanations). Others because they seem plausible, are exciting, have a veneer of scientific language, and spread faster than a solid debunking can — like a pole shift causing superstorms or that Betelgeuse will explode in 2012. These specific claims come and go, but stuff like them will always be around.

I don't see much trending going on, but I haven't done the statistics. :) But as long as we have instantaneous communication (like Twitter) and a population that isn't familiar with the science, we'll always have this problem. Heck, *astrology* trends on Twitter all the time (probably once a month; I should check that!). Sheesh.

Cold Fusion
afabbro

Ever since I read Gary Taubes' "Bad Science," I've been unshakably convinced that cold fusion is an example of pathological science, and Pons/Fleischman's "room temperature fusion" was utter nonsense.

However, CF believers seems to soldier on year after year. As recently as 2009, the U.S. Navy Space and Naval Warfare Systems Center reported finding neutron bursts when using heavy water electrolysis, though their claims were not accepted by the mainstream scientific community.

Has anything emerged since the debunking of Pons/Fleischmann that gives any credence to cold fusion?

Anything real? Nope.

That was easy. :)

Seriously, there will always be perpetual motion believers, no matter what the science — and overwhelming evidence — shows. There may yet be a real version of cold fusion, but it's clear that Pons, Fleischmann, and companies like Steorn are wrong. But when has being completely and utterly wrong ever stopped people?



Anthroporelevence
EdZ

You've made your position fairly clear on whether the current recent warming trend in global temperature is anthropogenic. My question is: do you think a mere reduction in (or cessation of) anthropic CO2 emissions will significantly reduce this trend, and whether larger scale geoengineering is an inevitable requirement to maintain the abnormally long stable warm period that humanity has thrived in for the last few millennia?

I'll be honest: I have no idea. That's something you'd have to ask the experts about. It's entirely possible it's too late to do much, or maybe we still have some time. But it's going to be impossible to get *anything* done until the global warming deniers in government are tossed out, or at least made less powerful. When the head of the House Energy and Commerce Committee says humans don't cause climate change (and so many sitting members of that committee are out-and-out climate change deniers), getting substantive change implemented is impossible.

Mad Scientist
Restil

Any chance of ever bringing back your Mad Scientist section, where you do a Q&A sort of like the Straight Dope, only with generally more Astronomy related topics? That's the particular feature that caused me to discover your site in the first place.

First, thanks! It was fun to do that, but incredibly time consuming. However, I have plans...stay tuned. :)

Star Trek or Star Wars?
jellomizer

Which do you find more annoying: Star Trek which can spend a good portion of the show trying to explain how and why they break the laws of physics? Or Star Wars, which breaks the laws of physics but doesn't care to explain itself?

Trek. Done and done.

Star Wars was space opera, and never depended on the science. Trek was more science fiction, but the writers really blew it many times with the saving of the ship at the last second with technobabble; that's not science fiction, it's a plot device. Still, Trek did have lots of good science in it, and the point I like to make is how many people it inspired to become scientists, me included. And more shows these days are using science advisors, though of course if the plot demands twisting the science, oh well. I live with it, because I like a good story, too!

Uranus
TheDawgLives

How do you pronounce the name of the seventh planet from the Sun? I'm in favor of Futurama's solution: rename it to Urrectum.

I claim that's the only funny joke that's been made about the planet. Leave it to Futurama!

I personally pronounce it "YOOR-in-us", but it probably should be "oo-RAN-us". There's a lot of confusion over this, references to butts notwithstanding.

Doing this for some time
by 0racle

You've been doing The Bad Astronomer thing for a while. How come you haven't become a better astronomer by now?

They say the sky's the limit, and to me that's really true, because I'm bad, I'm bad, come on, you know it.

Just to tell you once again, who's bad?

oneiros27 writes "For those astronomy fans out there -- pictures are starting to come in from the 2004 Venus Transit (where Venus passes in front of the sun). Times of the transit will vary by city, but make sure you use safe techniques for viewing the sun if you want to look for yourself." Anonymous Coward writes "Check out the transit of Venus webcast from Australia. It starts at 4.50 UTC on June 8." Update: 06/07 04:03 GMT by T : Linked webcast link updated to a URL projected to better handle the load, thanks to reader Tom Minchin.