@lecture @physics @james-webb @talk @astrophysics
03/02/23 11:55:04
JWST, Revealing the Infrared Universe.
- JWST sits in wavelength between Spitzer and Hubble.
- Hubble is at room temp. because it’s low earth orbit.
- JWST and Spitzer need to be cold to look at infrared spectrum.
- Primary case was looking deeper into space, at the first galaxies.
- Hubble made first observations of earliest galaxies in 1995, first time we really got to see these galaxies, that were born close to the big bang (Hubble deep field).
- There’s not many stars, the early galaxy are a lot smaller and irregular, so there’s evolution in galaxies (whole new branch of astrophysics).
- Hubble allowed us to see to ~480 million years after the big bang. JWST is pushing towards 200 million years.
- Mid infrared penetrates dusty areas.
- JWST can take spectra of multiple objects in the field at the same time.
- Could take spectra of objects (used to calculate red shift) in couple of hours (compared to weeks for Hubble).
- Micrometeorites will gradually degrade optical quality of the mirror. Trying to point away from direction of motion (to reduce energy of impact).
- Radial velocity for finding exoplanets, the planet tug on the star a small bit, so if we look at radiation from the star, it gets slightly doppler shifted.
- Direct imaging techniques requires being able to have a fairly iterative interaction with telescope (I would assume).
- PSF subtraction to resolve the planet from the light of the star. Resolve picture of the star without the planet, then with the planet. Direct imaging.
7 times more time is requested than time on the observatory. Proposals are ranked by peer review. Hoping they’re spread out in the sky (and presumably in area of interest).
Useless thoughts
In astronomy, the information (bits) is essentially quanta of light. How do we use computation on these bits? Also, having that ultimate limit to reality, what does that block us off from?