X-ray Astronomy Talk

Posted by barb on Feb 18, 2005 in Science Musings, Thesis/Grad Life

Andrew announced this weeks ago, but I forgot. I’m giving the talk on Sunday at the University of Maryland’s observatory open house. The talk is titled “X-ray Astronomy: An FAQ” (contrary to what it’s listed as at the observatory site…I wasn’t certain what the talk was going to be when I signed on). Basically, it’s a broad overview of what X-ray astronomy is and why we do it. So, if you’re in the DC area this weekend, come join us.

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Confirmation that Summers is an idiot

Posted by barb on Feb 18, 2005 in Science Musings

The transcript of Summers’ speech from a few weeks ago is now available on-line. You know the one — the one that pissed everyone off, where he dismisses discrimination as a factor for the underrepresentation of women in science and engineering. I bitched about it and then tried to react more calmly. The more fool, I. Summers is a dick (as Bitch Ph.D. has so eloquently pointed out). Read the transcript for yourself.

There are three broad hypotheses about the sources of the very substantial disparities that this conference’s papers document and have been documented before with respect to the presence of women in high-end scientific professions. One is what I would call the-I’ll explain each of these in a few moments and comment on how important I think they are-the first is what I call the high-powered job hypothesis. The second is what I would call different availability of aptitude at the high end, and the third is what I would call different socialization and patterns of discrimination in a search. And in my own view, their importance probably ranks in exactly the order that I just described.

So, discrimination and socialization might be a factor, but they are really secondary to innate differences? That’s contrary to other findings (thanks to Sean at Preposterous Universe for posting that plot).

When there were no girls majoring in chemistry, when there were no girls majoring in biology, it was much easier to blame parental socialization. Then, as we are increasingly finding today, the problem is what’s happening when people are twenty, or when people are twenty-five, in terms of their patterns, with which they drop out.

Yeah, and what’s happening is that at 20 or 25 they are finding that there is a lot of discrimination; there are barriers that are built either by society as a whole or the science community itself that are difficult for women to break through. Just because people are dropping out later in their career is not “evidence” of an innate deficiency. It just means that the pressures against continuing in that career appear later rather than sooner.

So my best guess, to provoke you, of what’s behind all of this is that the largest phenomenon, by far, is the general clash between people’s legitimate family desires and employers’ current desire for high power and high intensity, that in the special case of science and engineering, there are issues of intrinsic aptitude, and particularly of the variability of aptitude, and that those considerations are reinforced by what are in fact lesser factors involving socialization and continuing discrimination. I would like nothing better than to be proved wrong, because I would like nothing better than for these problems to be addressable simply by everybody understanding what they are, and working very hard to address them.

So here he says outright that aptitude is the problem, followed distantly by socialization and discrimination.

He actually has a few reasonable points, unfortunately it takes too long to get to them. It’s not until the second-to-last paragraph, just before he opens up for questions, which is frankly too late, because I’m already pissed off and seething.

I’ve been struck at Harvard that there’s something unfortunate and ironic about the fact that if you’re a faculty member and you have a kid who’s 18 who goes to college, we in effect, through an interest-free loan, give you about $9,000. If you have a six-year-old, we give you nothing. And I don’t think we’re very different from most other universities in this regard, but there is something odd about that strategic choice, if the goal is to recruit people to come to the university.

He actually addresses one of the root problems — the problem of childcare and encouraging younger qualified applicants who might be just starting a family.

We would like to believe that you can take a year off, or two years off, or three years off, or be half-time for five years, and it affects your productivity during the time, but that it really doesn’t have any fundamental effect on the career path. And a whole set of conclusions would follow from that in terms of flexible work arrangements and so forth….But it would be useful to explore a variety of kinds of natural interruption experiments, to see what actual difference it makes, and to see whether it’s actually true, and to see in what ways interruptions can be managed, and in what fields it makes a difference.

This is exactly what the sociologist at the AAS in Denver last summer was discovering. For anyone to make it to a tenure-track position, they need a “straight trajectory” — taking time off for anything (starting a family, caring for a sick parent, burnout) seemed to be a near kiss-of-death for a student’s career.

Perhaps the last few questions that Summers raised, buried at the end of an infuriating speech, would have been a better jumping-off point for his talk, rather than “provoking” us with idiotic statements that innate differences are the primary cause for the unequal representation of women in science.

[via Bitch Ph.D.]

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How far is a candle visible to the human eye?

Posted by barb on Feb 8, 2005 in Science Musings

One of the questions I got last week through the Ask a High Energy Astronomer website was asking if a candle, burning in a vacuum (we’ll let that part slide) would be visible from a great distance. The idea is that if there is nothing in the way to absorb the light, then we should be able to see the candle.

However, this does not take into account the decreasing flux from that candle. There are only a finite number of photons emitted by that candle, and those are emitted isotropically (equally in all directions). The number of photons, then, impinging on a surface, say, your eye, will decrease as the distance of the candle increases.

Out of curiosity I decided to do a quick calculation to see how far away the candle could be before it was just detectable by the human eye. I didn’t send this off with my answer, because I wasn’t sure of the calculation, and the person indicated their level as “novice”, so they probably wouldn’t have been enlightened by the calculation anyway. Just for posterity, here is my “scratch pad” calculation.

A few quantities to start with:

  1. From Lumens, Illuminance, Foot-candles and bright shiny beads.,
    the output of one candle is: 1/685 W per steradian
  2. From Light Measurement Handbook: The Power of Light, the threshold of the human eye is: 3.58e-18 W

From (1), we can first get the total power output by that candle, assuming isotropic emission, and using the fact that there are 4*π steradian in a full sphere.

Lcandle = 4π/685 W

The flux of that candle at a distance, R, is then:

Fcandle = Lcandle/(4πi*R2) = 1/(685*R2) W

Now from (2), we can find the threshold flux that the eye can detect. Assume that the eye has a light-collecting area equivalent to a circle with diameter 1 cm, then:

Feye, threshold = 3.58e-18 W/π*(0.005 m)2 ~ 4.56e-14 W/m2

Finally, by equating the two, we can find the distance at which the candle will be just detectable:

Feye, threshold = Fcandle


4.56e-14 W/m2 = 1/(685*R2) W
R2 = 3.2e10 m2
R ~ 1.8e5 m

That’s just 180 km, which is less than the distance between New York City and Washington DC.



Diminished by Discrimination We Scarcely See

Posted by barb on Feb 7, 2005 in Science Musings

Diminished by Discrimination We Scarcely See, an article from yesterday’s Washington Post, by Meg Urry, a professor at Yale University, and an all-around-powerful force for women in astronomy.

That’s the thing: Discrimination isn’t a thunderbolt, it isn’t an abrupt slap in the face. It’s the slow drumbeat of being underappreciated, feeling uncomfortable and encountering roadblocks along the path to success. These subtle distinctions help make women feel out of place.

I don’t have anything to add. Just read it.

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NASA Spinoff

Posted by barb on Feb 2, 2005 in Science Musings

Every once in a while, when I’m hotseatting for Ask a High Energy Astronomer, someone will ask a question to the effect of “What good is NASA-developed technology for the rest of us on Earth?”

The first time I was asked, I remember finding a great FAQ on the NASA home page. However, since the redesign of the “NASA portal”, I have been unable to find that page. Today I was able to find a great resource for this question on the NASA pages — Spinoff. Spinoff is an annual publication, since 1996, that chronicles some of the ways that NASA technology has been successfully implemented commercially. A few of the cool applications in the 2004 issue include:

  • In the field of health and medicine, A Look from the Inside:

    NASA’s Hubble Space Telescope has given the world amazing images of the distant stars, planets, and galaxies. The cutting-edge imaging technology that enhances the Hubble images also extends its benefits to life here on Earth, from deciphering previously unreadable portions of the Dead Sea Scrolls to improving digital mammographies for advanced cancer detection. This imaging technology is now helping physicians to perform micro-invasive arthroscopic surgery, which is the visual examination of an interior joint such as the knee.

  • In the category of Public Saftey, Sizing up the Situation: NASA developed technology to provide a scale for pictures without requiring a ruler or other reference object. This is accomplished by attaching a device to the camera that emits two parallel laser beams. These lasers project a pattern that appears in the pictures, allowing accurate distance measurements of up to about 200 feet.

    Information on the device is being distributed to crime laboratories around the world. Law enforcement photographers that take pictures of crime scenes can use the Laser Scaling Device to shoot scaled photos of blood-spatter patterns, graffiti, or other components of crime scenes that can be portrayed in a two-dimensional medium.

  • In the category of Computer Technology, From Video to Photo:

    A critical imaging code used to enhance video footage taken from spaceborne imaging instruments is now available within a portable photography tool capable of producing an optimized, high-resolution image from multiple video frames.

The main Spinoff page also includes links to technologies used in everyday life on Earth from Apollo mission development and technology development for the Space Shuttles. These are fairly impressive and includes the development of kidney dialysis machines from a chemical process developed to remove toxic waste from used dialysis fluid (Apollo mission-related) and the development of hand-held extraction tools for rescue squads to remembe accident victims from wrecked vehicles using a miniature version of the explosive charges that separate devices on the Shuttle.



News from the Universe: 02/01/05

Posted by barb on Feb 1, 2005 in Science Musings

January was a busy month for astronomy!

  • The biggest news, of course, is the Huygens probe. For those of you living in a bubble, Huygens is the probe that was carried to Titan, one of Saturn’s moons, on the Cassini spacecraft. It was released on January 14 and decended through Titan’s atmosphere to land with a splat in Titan “mud”.

    The reason scientists are so interested in Titan is that next to the Earth, it is the only other body with a significant atmosphere in our solar system. Huygens has already shown that there is a significant amount of methane in the atomosphere, which is a surprise because methane gets destroyed by ultraviolet radiation. Since our sun emits an abundance of UV radiation, this methane on Titan must be renewed somehow, or it would all be gone by now. The main source of methane on Earth is life; however the methane on Titan is not from life. This leaves the scientists with a puzzle to work on.

    You can keep up with the latest news on the Cassini-Huygens mission at Space.com.

  • On January 17, Swift detected and imaged it’s first gamma-ray burst. Swift has been going through it’s testing phase, and has observed other gamma-ray bursts, but this is the first one that Swift detected and autonomously slewed to observe. It is the first time that a burst has been observed in X-rays while the burst was still going on.
  • Deep Impact successfully launched on January 12. This is a mission that will rendezvous with comet Temple I and send an impactor to the comet. This will give astronomers a first look at what’s beneath a comet’s surface. The rendezvous should occur on July 4th.
  • Hipparchus’ star chart found in plain site. Hipparchus was the greatest astronomer of antiquity and produced the first star chart around 129 B.C., which has been lost. Only a few bits of his work remain. The Farnese Atlas sculpture, dating from the late Roman period, sports a globe with constellations etched into it. Bradley E. Schaefer of Louisiana State University was able to deduce, from precession calculations, that the positions of the constellations coincide with the time of Hipparchus, and are likely based on his star catalog.
  • SOHO is having a contest to see who can predict when it will discover it’s 1000th comet. SOHO was not built as a comet detector — it’s a mission to monitor the Sun. However, it has now detected over 900 comets, and is the most prolific comet-finder in history. You can enter here, and the prizes for guessing correctly include SolarMax DVD, a SOHO T-shirt, and solar viewing glasses.
  • Just for fun, Mr. Potatohead hss turned to the dark side.

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Posted by barb on Jan 29, 2005 in Thesis/Grad Life

For the last year and a half I have known, without a doubt, that I don’t like doing science. I love astronomy, but I don’t love doing astronomy. This means that every time I sit down to work on my thesis, I wonder to myself why I’m doing it? Why am I wasting my time? Why don’t I just quit?

I know the reasons I’ve kept going: I’ve wanted a PhD for as long as I can remember, I know that I can do it, and I’m already this far along, so I might as well finish. They might not be good reasons, but there they are. Frankly, they haven’t been enough. And along with the messages of “Why am I doing this?” that I’ve been feeding myself, I’ve found it very difficult to muster any enthusiasm for my work. This means that I’ve been getting very little done, and subsequently is going to prolong my grad work.

In addition, I’ve been finding that I don’t take myself seriously at all. I feel like I’m “just a grad student”, and at 33 that makes me a nothing. At least that’s how I’ve been feeling. It’s not good, it’s not true, but it’s going through my head continuously.

Enter my epiphany.

Read more…

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Cereal Box Astronomy

Posted by barb on Jan 28, 2005 in Pictures, Science Musings

Tonight, at the grocery store, I picked up a box of the store brand cereal. Before I could get it into the cart, Andrew pointed out that it had constellations on the back, so we looked a bit closer. There was a star chart with a few constellations, a couple “facts” about the night sky, and a game matching the constellations to information about the constellation. Cool, right?

Well, Andrew noticed a small typo immediately:
Cereal box astronomy

Don’t see it? Sagittarius is spelled with two ‘t’s. Okay, no big deal — it’s just a small typo. Oh, and they repeated this typo in the answers to the constellation matching game!

But then there was another one:
Cereal box astronomy

“A great way to learn about the night sky is to get a start chart”…hum, I think they meant star chart, not start chart. Well, okay. This was the store brand, afterall. They’re entitled to a couple typos for the greatly reduced price, right?

Maybe, but this mistake is just too big to excuse:
Cereal box astronomy

That’s right, the naked eye can see a whole galaxy that’s closer than the nearest star!

Clearly this was just the omission of the word “million” (2.5 million light years away), but even discount cereal boxes need to have some level of accountablility.

You can check out the back of the box
Cereal box astronomy

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Finding Feynman

Posted by barb on Jan 28, 2005 in Science Musings

Someone sent me the link to Alan Alda’s commencement speech at Caltech in 2002 [PDF]. He was asked to give the commencement speech because of his work on a play about Feynman, who was at Caltech when he won his Nobel prize in 1965 (one of my professors was attending Caltech when Feynman won the Nobel — apparently it was the only day he ever wore a tie).

I’m assuming you’re here at Caltech because you love science, and I’m assuming you’ve learned a great deal here about how to do science. I’m asking you today to devote some significant part of your life to figuring out how to share your love of science with the rest of us.

But not just because explaining to us what you do will get you more funding for what you do . . . although it surely will . . . but just because you love what you do.

And while you’re explaining it, remember that dazzling us with jargon might make us sit in awe of your work, but it won’t make us love it.

Tell us frankly how you got there. If you got there by many twists and turns and blind alleys, don’t leave that out. We love a detective story. If you enjoyed the adventure of getting there, so will we.

Most scientists do leave that out. By the time we hear about their great discoveries, a lot of the doubt is gone. The mistakes and wrong turns are left out . . . and it doesn’t sound like a human thing they’ve done. It separates us from the process.

Whatever you do, help us love science the way you do.

It seems that we have gotten so bogged down in our world of science that we’ve forgotten to share it with the rest of the world. One of the largest problems facing the science community today is that people don’t understand what the scientific process is. They don’t understand that scientists develop theories only after compiling data and observations. They don’t understand that theories are well-developed explanations of those data and observations, not merely “hunches” or “guesses” at what might explain those data. They don’t understand that just because a new observation challenges one part of a theory, the theory is not immediately defeated. Instead, the theory is examined closer and altered to explain not only the new data point, but to cover the entire collection of data and observations. Above all, they don’t understand that “dead-ends” are very much a part of science, and unanswered questions are not a mark that we don’t know what we’re doing, but a path leading us to work that needs to be done.



HST Servicing Plans Axed

Posted by barb on Jan 22, 2005 in Science Musings

Let’s say you have two choices: putting some money into servicing an established, functioning, NSF-endorsed satellite that is returning amazing science results for over 10 years, or putting that money into a pie-in-the-sky, underfunded, and ill-concieved plan to send humans to Mars. If you’re the administration in the White House, you choose the latter.

White House Cuts Hubble Servicing Mission from 2006 Budget Request:

The White House has eliminated funding for a mission to service the Hubble Space Telescope from its 2006 budget request and directed NASA to focus solely on de-orbiting the popular spacecraft at the end of its life, according to government and industry sources.


That budget request, according to government and industry sources, will not include any money for Hubble servicing but will include some money for a mission to attach a propulsion module to Hubble needed to safely de-orbit the spacecraft with a controlled re-entry into the Pacific Ocean. NASA would not need to launch such a mission before the end of the decade to guide the massive telescope safely into the ocean.

No one is saying that the exploration BS initiative is the cause of the HST servicing mission getting cut from the budget. However, it was about a year ago that the exploration initiative was announced, and it was about a year ago when they first talked about cutting the HST servicing mission.

According to the article, “With both robotic and shuttle-based servicing options expected to cost well in excess of $1 billion, sources said, NASA was told it simply could not afford to save Hubble given everything else NASA has on its agenda, including preparing the shuttle fleet to fly again.” Hmmm. $1 billion. Wasn’t that the extra that NASA was supposed to get for the exploration initiative (Plus $10 billion redirected from existing NASA programs)? What a coincidence.

The final approval for the budget, however, comes from Congress. This might be a good time to write a letter to your local congress members.

[via Preposterous Universe]

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