I never heard of flying a telescope on a sounding rocket before.
“DEUCE is about being able to better understand if and how star-forming galaxies ionized the early universe,” said Nicholas Erickson, a graduate student at the University of Colorado Boulder working with the project. “This ionizing light has never been measured accurately in hot stars, and DEUCE will make the first calibrated measurement of it, telling us the contribution stars could have had to helping ionize the universe.”
Over two flights, DEUCE will look at two young, bright stars — first Beta Canis Major and later Epsilon Canis Major — using a telescope sensitive to ultraviolet light. These stars are close enough that their light reaches Earth before being fully absorbed by interstellar gas, allowing the scientists to measure the amount of starlight to see if it’s enough to significantly contribute to the amount of ionized gas in the IGM.
http://go.nasa.gov/2A0adUq
Well duh.... Does the sun shine and warm your skin? Yes. Is light from any star going to ionize any gas present? Yes. Are they going to make an accurate measure of this ionization. I don't know. Would a more accurate measurement be possible with longer duration measurements from a stabilized platform, such as say, ...a satellite, ...in orbit?. ...Probably.
ReplyDeleteThey are using a sounding rocket because they don't have the budget to put up a satellite.
I'd be much more interested in a measurement of the broadband attenuation that the IGM provides because I believe current measurements concerning the total size of the universe are way off, and that scientists have not accurately mapped or measured the quantity of matter in the universe yet.
Dirk Collins Only photons bluer than the first ionization potential of (say) hydrogen will cause dissociation - and the vast majority of photons are far colder than that. Distances in the universe rely firstly on parallax (nearby) and then brightness/mass ratios (Cepheids an' all that jazz).
ReplyDeleteEven redshift methods would be coarsely insensitive to absorption bands - so to first order, the Universe is probably as big as it seems to be.