Blogs / Bad Astronomy

Astronomers have found one of the oldest known stars. And it’s old: 13.2 billion years old. The Sun, by comparison, is 4.6 billion years old. A veritable baby!

Dating a star is hard (in both senses of both words), but there are telltale signs of age. One thing you can do is look for stars that are almost entirely hydrogen and helium, and there’s a good chance they’ll be really old. In the early Universe, those two elements were pretty much all there was. When the first generation of stars formed, they created heavier elements like carbon, oxygen, and even much heavier elements like iron and so on up the periodic table. When they exploded they scattered those heavy elements around them, which eventually became part of dust and gas clouds which formed the next generation of stars. So younger stars tend to have more heavy elements than older stars. If you’re looking for old stars, you look for ones with higher proportions of light elements. They may still have heavier elements in them, just not as much as younger stars, which formed from clouds which had successive generations of exploding stars seed them with ever more heavier elements.

That’s just what Dr. Anna Frebel from The University of Texas at Austin McDonald Observatory and her team did. They had a sample of stars they knew were pretty old, because they were mostly hydrogen and helium. But how old were these stars? "Pretty old" just doesn’t cut it. They wanted numbers.

So they turned to a natural clock that appears in stars: radioactive elements. In this case, specifically uranium, europium, thorium, and osmium. By measuring how much of these elements are in the star and knowing their decay rates, it’s possible to determine how long they’ve been sitting in that star. Since the elements were created shortly before the star was born, this gives you a pretty good estimate for the age of the star!

How do you do that? Well, you take a spectrum. You spread the colors of the light out, and measure how bright each color is. Different substances emit and absorb light at very specific and different colors. I’m simplifying, of course, but that’s the basic idea. One clear indicator of oxygen in a gas cloud, for example, is bright emission of light in the green part of the spectrum, at a wavelength of 501 nanometers.

So uranium has its own set of colors. If you can find them in the spectrum, you can figure out how much uranium there is. And that’s what Dr. Frebel and her team did. They pointed their spectrograph at the star HE 1523-0901, and this is what they got:

The wavelength (color) on the x-axis is in the blue end of the spectrum, and the y-axis is brightness. The dots are the measured spectrum. All the dips in the brightness represent light being absorbed by different things. In this one you can see iron (Fe), magnesium (Mg), and even, wow, neodymium (Nd). The dip at 3859.6 Angstroms is from uranium absorption.

You can use physics and math and predict how much uranium you’d expect to see based on the age of the star and the amounts of other elements. If there were no uranium at all you’d see the spectrum where the solid blue line is. But the amount of uranium indicates the star in question in 13.2 billion years old. This was substantiated by other dating methods as well (including measuring europium, osmium, and iridium).

Wow. That means this star formed just 500 million years after the Big Bang. The very first stars formed about 400 million years after the BB, so this star coalesced only 100 million years after those stars first did– it may be from the very first stars in that second generation. Think of the changes since then! The Universe was far smaller and warmer when that star was first born. The Milky Way was brand new, and the birth of the Sun was still 9 billion years in the future. This star was old when the Earth was born.

That’s amazing work. I wonder what else this star can tell us? The abundances of the other elements may tell us about those very first stars, the ones that blew up and created the first heavy elements. I bet that eventually, the abundances in this star will tell astronomers more about how massive and how hot the first stars were. One the coolest things about science is that all the pieces fit together. They have to. Science is how we figure out reality, and I’m pretty sure reality works.

Oh, by the way, Abe Vigoda is alive.

“The more they overthink the plumbing, the easier it is to stop up the drain.”

Remember I wrote a while back on how James Doohan (Star Trek’s Scotty) had some of his ashes launched on a suborbital rocket into space?

Well, it turns out that the payload is, um, missing. It fell in some difficult to reach terrain, evidently, and the rocket company, UP Aerospace, can’t find it. It’s in dense vegetation, and while they know where it is to within a few hundred meters, they’re having a hard time tracking it down (thought the article linked above implies there is a transmitter on the rocket payload which should make finding it a lot easier). They’ll try again next week, though it’s unclear why they’re waiting that long. The weather there looks pretty clear right now.

LiveScience.com has an earlier article about this, too. Not so incidentally, Mercury astronaut Gordon Cooper’s remains were on the payload, too.

I was surfing around Digg.com the other day, looking at what the community there had been linking to as far as science articles go.

Somebody had linked to a great article on Quackwatch about how to distinguish pseudoscience from real science. The article has been around a while, but clearly it was popular at Digg; getting more then a few dozen Diggs (votes for popularity) is tough — I’ve had only a handful of blog entries that have hit it reasonably big at Digg. Yet this article was doing really well. Check out the apropriate number of hits it had when I looked:

Man that guy gets around. First a license plate in New Mexico, and now Digg!

Wildfires are sweeping through the country right now. A mixture of high temperatures, low humidity, and low rainfall has created terrible conditions; I’m surprised none has started where I live (though it did rain a bit last week).

In southern California, specifically LA, a huge fire tore through Griffith Park, a lovely area in the heart of LA. Sitting atop a hill there is the venerable Griffith Park Observatory. Built in 1935, it just underwent a $90+ million expansion and renovation.

It was in serious danger from the fire, but it appears to be OK (you can see dramatic images of it on Flickr, like the incredible image above). I’ve been keeping an eye on this… in November of 2004 I was in Australia on a speaking tour, invited by the National Skeptics for their annual conference. I had an amazing, tremendous, bonzer time. I love the area, the people, the coffee, just everything there.

But there was one somber moment. With some friends I toured four world-class observatories down there, including Mt. Stromlo, which is near Canberra, the Ozzie capital city. In January 2003, a fire of apocalyptic proportions burned in the Canberra hills, and in this case there was no happy ending: the observatory was almost totally destroyed.

When I toured the area, it was still completely ravaged. There were burned trees everywhere, live oaks and eucalyptus, the same kind we have in northern California (the whole area was strikingly similar to Sonoma County, in fact, which was very disconcerting — I’d just be thinking how much it looks like home, when a pack of wallabies would hop across the road). And the observatory… oh, the observatory.

The domes were destroyed. Some had collapsed, some had been taken away. In one, the mount structure for the telescope was still inside, and they wouldn’t let anyone in. There were many tons of unstable steel in there.

I could see paint peeled away from the metal domes due to the intense heat of the fire.

And then we went to the 50 inch.

I knew this telescope. I had never used it, but I have friends who had, and I’d seen pictures of it in happier days. How many papers on the MACHO project had I read, observations done on this grand old lady? But not any more. The telescope, like many big instruments, was an open truss structure. Steel pipes had held the mirror in place, but the fire had softened them, and the whole thing had swung down. Bizarrely, the mirror hadn’t melted: the glass had shattered in place. We walked right up to it, and we could still see that it held a parabolic shape, but instead of one piece of glass, it was now several thousand, like someone had taken a hammer to it.

One piece near me stuck up a bit, and without thinking I reached over and pulled it out. It was maybe three inches long, and one end came to a wicked point. I just stared at it, and our guide told me I could keep it. I remember just staring at it… I still have it. It’s packed away, ready to move to Colorado, or else I’d put up a picture of it. I keep it around to remind me that sometimes, solidity is an illusion.

Still, you can’t keep Australians down. I wouldn’t even hope to try! They’re rebuilding the observatory, of course. I just can’t say enough good things about Australians, including them having their heads screwed on straight — well, most of ‘em do. But that crazy upside-down place is enough to turn anyone into a drongo.

So. I’m glad that Griffith Observatory is out of danger. I’m not sure I can take the destruction of another wonderful place where people get a chance to touch the stars.

Artist’s conception of the planet HD189733b.

Wow, more cool extrasolar planet news.

Using the Spitzer Space Telescope, astronomers have been able to make, for the very first time, a (very crude) map of the super-Jupiter orbiting the star HD 189733, about 60 light years away. The planet was discovered in 2005 (note this is not the new "Earthlike" planet found recently, this is a big gas giant like Jupiter) and is one of a handful that passes directly in front of its star as seen by us on Earth. In other words, it transits the star, making a little eclipse once per orbit.

Transiting planets are very useful: by measuring how much the starlight drops, we can measure the size of the planet! The bigger the planet, the more the light from the star dims. This gives us a direct measurement of the planet’s radius.

But it also allows a cool technique to measure features on the planet, too. Imagine there is a really bright spot smack dab in the middle of the planet. As it orbits the star, the planet gets blocked by the star. We see the total system brightness drop (because the planet contributes a little bit of light). But when the bright spot gets blocked, the brightness would make a sudden dip. And if instead of a bright spot, we had a dark spot, when it got covered by the star, the brightness would not drop as quickly.

So by very carefully measuring the way the brightness changes as the planet goes behind the star, we can actually make crude maps of planetary features, even though the planet itself is far too small to resolve into a disk. This technique has been used to make maps of Pluto and its moon Charon, in fact.

But doing it for an extrasolar planet is a bit tougher! They are incredibly dim, and the stars very bright. But it’s possible, and so Heather Knutson, a graduate student (!!) at the Center for Astrophysics and her team did just that using Spitzer! Voila:

Like I said, the map is crude (yet it represents 33 hours of observations and a quarter million data points!), but it does show one obvious feature. Spitzer measures infrared light, so brighter objects in this case are warmer. That bright spot is a hot spot they found, which is roughly twice the size of Jupiter’s Great Red Spot (which itself is several times bigger than Earth!). As it happens, the planet spins once for every time it goes around the star, so it always shows the same face to its star (the same way the Moon always shows the same face to Earth). So you might expect the hottest part of the planet to be right under the star, where the star is always directly overhead. But that’s not the case; the hot spot is actually about 30 degrees away from the "substellar point". Knutson speculates that this is due to winds on the planet; a sort of alien jet stream. That sounds plausible to me.

At the moment this is the best map that can be made. But over time, as they make more observations, it is possible to improve on this map. Are there other warm spots? Are there cool spots? Can we learn more about the big spot? After all, all we know is its rough size and where it is, but not its shape. That might be possible to determine, though I can’t imagine how difficult the observations would be!

This is a fantastic step forward, and it makes me even more excited to think about what we might learn in the next few years. It takes advanced technology, but it also takes clever people to figure out how to use it to its best advantage. As it happens, we have both.

When the Democrats took back the House in 2006, Henry Waxman (D CA) took over as chair of the House Oversight and Government Reform committee (actually, when he took it over, the word "Oversight" was not in the committee’s title, as his predecessor had removed it — I mean, hey, after all, why should the government need oversight?).

Waxman has been very, very busy trying to find out just where the government – both Congress and the White House — has stepped over the line of the law. Recently, it came to light that the White House has been giving presentations to government agencies and using these as platforms to promote the Republican party. That is a very bad no-no. So on April 27, Chairman Waxman sent out letters to many Agency heads, asking if there have been any shenanigans, and that includes a letter sent to NASA’s Mike Griffin.

I figured BABloggees might be interested in this. It’s not an indictment of anyone at NASA, just a letter to see if the White House has been pushing a political agenda.

Dear Administrator Griffin:

I am writing to request information about political briefings given by White House officials to federal agency officials.

On March 28,2007, the Committee held a hearing during which Lurita Doan, the head of the General Services Administration, testified that White House officials in the Office of Political Affairs conducted a political briefing at GSA headquarters on January 26,2007. The briefing slides, which the Committee reviewed, identified the Republican Parfy’s top electoral targets in the 2008 elections. After the presentation, Lurita Doan asked her staff to discuss how GSA resources could be used to help “our candidates” in the next election.

An article in today’s Washington Post reports that White House officials now confirm that, in the past year alone, at least 20 similar briefings were given to officials of at least 15 federal agencies, including the Interior Department, the Environmental Protection Agency, and the Commerce Department, among others.

To assist with the Committee’s continuing investigation of this issue, I request that you provide information about any briefing mentioning elections or candidates provided to agency employees by officials in the White House between January 20,2001, and April 26,2007. Please provide the dates, times, attendees, and locations of these briefings, as well as any communications and documents relating to the briefings. Please provide these materials to the Committee by May 18,2007.

The Committee on Oversight and Government Reform is the principal oversight committee in the House of Representatives and has broad oversight jurisdiction as set forth in House Rule X. An attachment to this letter provides additional information about how to respond to the Committee’s request. I would appreciate your cooperation with this request.

I’ll be curious to see what happens here. A little while back, Administrator Griffin made a speech where he thanked Tom Delay (who is allegedly a major crook, but also a big supporter of NASA since he was a Representative from the district where Johnson Space Center is) and said, before Delay resigned, "He’s still with us and we need to keep him there." Many people interpreted that as an endorsement, for obvious reasons, which is also a no-no. It was a simple mistake on Griffin’s part — I don’t think he was really trying to stump for Delay, he was just endorsing someone who was a friend of NASA. Nevertheless, it was a violation of the Hatch Act, which restricts political appointees from politicking. It was a minor violation and no big deal, but it can’t be fun for Mr. Griffin to have to get the letter he did from Henry Waxman. I’m sure right now there are other things on his mind!

Update– The U.S. Office of Special Counsel investigated Griffin’s remarks, and found that he lacked judgment in making them, but nothing worse. Interestingly, they also investigated a broadcast on NASA Select by John Kerry, and also found it violated the Hatch Act; it looks like someone at NASA relied on "incorrect advice" and outdated NASA guidelines. Thanks to commenter JR Keller for pointing this out!

We’ll see how this plays out. This White House has been absolutely shameless in its suppression of science and its promotion of fundamentalist religion at NASA and elsewhere. It may be that no one spoke to any NASA employees and nothing will come of this particular letter. But the letter was sent to the heads of 26 other agencies, so we’ll see what happens.

In England, there is a long, long tradition of public outreach in astronomy. The leader of this is beyond a doubt Sir Patrick Moore, a man who is the UK version of Carl Sagan. His show, "The Sky at Night", has been running for decades, and he has made the skies accessible to everyone.

So I am very disappointed by comments he made today:

British TV standards are deteriorating because the BBC is “run by women”, astronomer Sir Patrick Moore has said.

[...]

The presenter said: “The trouble is the BBC now is run by women and it shows soap operas, cooking, quizzes, kitchen-sink plays. You wouldn’t have had that in the golden days.”

[...]

“I used to watch Doctor Who and Star Trek, but they went PC – making women commanders, that kind of thing. I stopped watching.”

This kind of misogynism is truly shocking to read, especially from such a distinguished and respected gentleman. I won’t even bother debunking this kind of trash; if it isn’t self-evident to you, then I won’t waste my breath.

A couple of years ago I was invited to go on the show as a guest of Sir Patrick’s — he is a Moon hoax debunker as well — but we couldn’t work out the details. Now I won’t go on even if they ask me again. It’s a shame, really, but since he’s made his views public, I don’t see much of a need to endorse him, tacitly or otherwise.

Tip o’ the monocle to Teek — who is a strong woman and worthy of my respect.