What is GLAST?

By Phil Plait | May 30, 2008 8:33 am

GLAST is due to launch on June 5 (it was moved back a couple of days since I last mentioned it), and so you can expect to start seeing more news about it. In fact, some videos have surfaced talking about GLAST, explaining gamma rays and why we want to observe them… and one of the vids has a familiar face in it.

The first is GLASTCast, a short video series about the gamma-ray observatory produced by NASA. Here’s a link to the first one, but I think I’ll embed the second one here for reasons that’ll be obvious right away…

It’s pretty cool to see so many old friends in the video. This series has a great look, and I hope they keep making them. You can get higher-res versions on the GLASTCast page.

But if you prefer things on the lighter side, then check out this French-made video about GLAST.

I thought that was pretty funny. Note: they say that by May 17 it’ll be in orbit, but this was clearly made before the latest set of delays. Also, they use the word "film", and I suspect that’s a translation issue; they mean "image", like a single picture. GLAST doesn’t use actual film.

Anyway, I’m pretty excited to see GLAST getting close to launch. It probably won’t create the sort of blockbuster images we’re used to from observatories that see more mundane forms of light, but the science returned will be fantastic. Still, I know that over weeks it’ll build up a whole-sky map of gamma rays, which should be pretty interesting. Some simulations show that a movie of sorts can be made too, showing how the sky changes in gamma rays as the Moon (which reflects gamma rays from the Sun) moves, as gamma-ray bursts come and go, and so on. That should be pretty cool.

Tip o’ the anti-coincidence detector to Marshall Roth for the French video, and to my old boss Lynn Cominsky for the GLASTCast notice!

CATEGORIZED UNDER: Astronomy, NASA, Science, Space

Comments (21)

  1. Gilles

    Bizarre, the Earth rotates in the wrong direction (0:45 to 0:56) and is vertical on its axis.

  2. Monkey

    So here is my take on these two;

    As a teacher, the first is superlative for my understanding and technical awareness…the second is best to show a class of grade 9’s and 11’s. I find both to have equal merits – kudos to both styles!

    Gilles: I read on a credible blog that Earth actually spins that direction, some guy named B. Stein….no wait, Ben. S….


    Anywo, thanks Phil…im showing it to the little gaffers today.

  3. Joker

    The Bad Astronomer hisself rhetorically asked :

    What is GLAST?

    Imagine a strong Jamaican accent for this :

    Hey izz Gee last thing mon! ūüėČ

  4. Nice videos!

    And in the French one, they don’t use “film” referring to the “image” meaning‚Ķ I think they actually meant “movie”. They say GLAST will be capable of taking movies of the sky in gamma rays, and they use the verb “to film” to say that ūüėČ

  5. Steven Charles Raine

    Apologies for going off-topic & maybe this is just me but for amateur astronomers (& proffesionals too) out there tonight :

    I’ve just looked up at the constellation of Scorpius and could swear there’s something different about it – that Theta Scorpii (Sargas) is brighter tonight than it used to be …

    By my guestimation it is now the second brightest star in the constellation – brighterthan Shaula (Lambda Sco) in the Sting & brighter than Graffias (Beta Scorpii) as well.

    I’ve just been looking up at it past zenith in Adelaide about 2 a.m. …

    Admittedly there’s been a bit of cloud around & okay I could be wrong but is there something odd happening with this star? Anyone know?

    Not sure if others here can see it but if you can if its dark & clear outside or when it gets dark folks please take a look – Sargas (or Theta Scorpii) is the star in the tail between Eta Scorpii & Iota Sco. It makes a triangle with the Shaula-Lesath pair and Iota 1 & 2 Sco & is diagonally across from the “leg /hockey-stick shape “asterism made of Shaula (heel), Lesath (toe) and Q Sco, Kappa & the Iota Sco’s (leg/handle) ..

    It seemed a lot brighter briefly earlier too around 10-15 -10.30 pm Adelaide (South Australia) time – even approaching Antares in brightness which it shouldn’t do! If my unaided eye guesstimate was right .. there wasmor ecloud around then plus a contrail through the area incl. over Theta Sco.

    For comparison :

    Sargas (Theta Sco) has an app. mag listed as 1.9

    Shaula (Lambda Sco) app mag = 1.6

    Antares varies from 0.9 to 1.2 mag.

    Source : Collins Guide to Stars & Planets Tirion & Ridpath,

    Sargas (Theta Sco) now appears at least equal to if not marginally brighter than Shaula to me …

    Am I imagining this or is it real? Can anyone here confirm, refute or explain?

    I’ve emailed the SA Astronomical Society too btw. (Of which I’m a member.)

  6. Steven Charles Raine

    Yes Dark Sapiens my Dad is English-Australian & we’ve always used ‘film’ as also meaning ‘movie’ in our family. 8)

  7. Nigel Depledge

    Very interesting. All good stuff there.

    BTW, would I be right in thinking that the calorimeter weighs the best part of 2 tonnes? With 1536 crystals of caesium iodide, each weighing over a kilo, that’s one heavy load of salt.

  8. Torbjörn Larsson, OM
  9. Torbjörn Larsson, OM

    Hmm. Dunny why the two links flowed together. Bad scripting?

    [And when are we going to get preview? Before or after the ISS is finished? :-/)

  10. Thanny

    NASA needs to take some public relations lessons from the French people who made that second video.

    And I’m sure DarkSapiens is correct – they are using the word film in the context of a motion picture. A movie is a film, and shooting a movie is filming a movie.

  11. This should really increase our chances of getting a good shot of a nascent GRB in gamma radiation. That would be too cool!

  12. JKH

    The music on the deuxi√®me video sounds suspiciously like that of Penn & Teller’s “Bulls *slap* Hit”. Hmmmm.

  13. Ronn Blankenship

    [Steven Charles Raine asks about Theta Scorpii.]

    If it had brightened enough to be seen through the clouds here tonight we might all be in trouble. ūüėČ

    That said, I haven’t seen any other reports yet about anything unusual.

  14. Steven Charles Raine

    Okay Ronn Blankenship thanks anyway.

    I didn’t actually think it was necesarily going supernova but I was wondering what was happening. I could’ve sworn it looked brighter than usual and brighter than stars it shouldn’t be brighter than.

    But maybe I was just mistaken … If so then sorry. :-(

    (Blushing, lowers eyes, tail between legs.)

    I still reckon it might payfor folks whocan tojustcheck this star tonightand for a while and make sure though …Could it be an emerging variable? Given its spectral type, perhaps a star just entering the Cepheid variable stage? Just speculating of course …


    Additional info on Sargas (Theta Scorpii) for the curious :

    “Another 4 degrees further along to the east [from Eta Scorpii – ed], we find Sargas, Theta, magnitude 1.87, marking the base of Scorpius’ upturned stinger … Theta is an F supergiant, about 650 light years distant with a luminosity of some 5,800 solar luminosities. Above 45 degrees north latitude , one cannot view it.”

    – Source : page 251, ‘The Constellations’, Motz &Nathanson, Aurum Press, 1991.

  15. Steven Charles Raine

    (Blushing, lowers eyes, tail between legs – again. This time over the expletives typos!)


    I still reckon it might pay for folks who can, to check out this star tonight and for a while yet though and just make sure though ‚Ķ just in case there was something odd going on there & it wasn’t just my active imagination and poor viewing conditions.

    Could Theta Sco be an emerging variable? Given its star type Рan F type yellow supergiant Рcould Sargas perhaps be a star just entering the Cepheid variable stage? Just speculating of course …


    Some more (& slightly conflicting) Sargas /Theta Scorpii data via the Celestia Planetarium software :

    Star type : F1 II (yellow–white bright giant (not supergiant according to this?)

    Absolute Mag : – 2.75 (or nearly minus three – thus almost as bright as Venus in our skies when about 33 ly away!)

    Luminosity : 1,070 times our Sun’s. (& I have enough trouble imagining something just twice as bright as our Sun!)

    Surface temperature : 7,500 degrees Kelvin

    Radius : 18.23 times our Sun’s.

    Rotation period : 141 days.

  16. Adam

    The 5th you say? My, what a great birthday present for me!

  17. Irishman

    Both sets of “film” are great. Comments:

    First, how did they get Quentin Tarantino to star in that video? (See GLASTcast E1, at 0:22.)

    Second, that French one is amusing, but a couple things stand out. Gilles notes the Earth spinning the wrong way. Also at 6:10 they are comparing the EGRET to GLAST, talking about how EGRET looked at one region of sky for a week or two before moving on, whereas GLAST will view the whole sky every 3 hours. They show both satellites orbiting Earth, but they are orbiting at different speeds. This implies GLAST will see the sky faster because it is traveling faster.

    I also note at :25 they state that NASA is superstitious and will only “christen” the telescope after it is in orbit. They state that the satellite will be renamed, possibly Enrico Fermi. I find this amusing on a couple counts. 1 is that while I have seen NASA rename a satellite after launch, I don’t recall superstition playing a part. It was AXAF, renamed “Chandra”. This was done because AXAF was pretty lame and Chandra was in honor of Subrahmanyan Chandrasekhar, an Indian-American Nobel Laureate. However, juxtapose this with, say, Galileo, or Cassini, or the Phoenix lander, or any other NASA project, where the names are dreamed up almost in parallel with the mission itself. Also, juxtapose that with the Japanese Space Program, that really does wait until the mission is launched to name it. Those silly French are confusing NASA with NASDA. ūüėČ

  18. StevoR

    What is GLAST?

    Well now we know its Fermi! ūüėČ

    The Fermi gamma-ray space telescope to be precise. 8)
    (Been renamed – thought we might as well update this thread here with that now old news too!


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