3a03 – gr and cosmology ralph pudritz dept. of physics & astronomy mcmaster university
TRANSCRIPT
![Page 1: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/1.jpg)
3A03 – GR and Cosmology
Ralph Pudritz
Dept. of Physics & Astronomy
McMaster University
![Page 2: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/2.jpg)
Hubble Space Telescope – time machine
This telescope has enabled our deepest probe at optical wavelengths, of the cosmos – the Hubble “deep field”.
![Page 3: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/3.jpg)
Looking back in time – galaxies long ago
This image, consists entirely of galaxies. Very faint ones are at cosmological distances:-smaller and “blotchier” than galaxies at present.-Evidence for for galactic evolution over cosmic time.
![Page 4: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/4.jpg)
Mapping where galaxies are – “large scale structure”
Da Costa et al (1994)
(Center for Astrophysics survey )
- 9,325 galaxies shown
- The largest structure yet seen: the “Great Wall”.
![Page 5: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/5.jpg)
Coma - cluster of galaxies
![Page 6: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/6.jpg)
THE EXPANDING UNIVESE Edwin Hubble:
1889 - 1953
At the 48 inch on Mt. Palomar
![Page 7: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/7.jpg)
Cepheid variable stars – measuring distances to other galaxies
![Page 8: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/8.jpg)
Hubble Diagram (1929): galaxies move apart!
![Page 9: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/9.jpg)
Galaxies move away from us - the same for observers in any other galaxy…
![Page 10: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/10.jpg)
Albert Einstein – General Relativity
![Page 11: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/11.jpg)
Fate of the universe - depends on how dense it is…
![Page 12: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/12.jpg)
Geometry of the universe in four dimensions….
Closed Universe Critical Open Universe
(sphere) (flat) (saddle)
![Page 13: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/13.jpg)
Discovery of microwave radiation – blackbody at 2.7o K
![Page 14: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/14.jpg)
COBE satellite – mapping the CMBR
![Page 15: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/15.jpg)
COBE map: temperature of universe 2.735 deg above absolute zero - image shows slight “dipole” Dpppler shift, picking out our direction of motion
![Page 16: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/16.jpg)
Cosmic Microwave Background Radiation - temperature fluctuations (one part in 105 )
![Page 17: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/17.jpg)
Inflation – making the universe flat
Cosmic Microwave background radiation is surprisingly smooth – universe probably “inflated” incredibly rapidly from one tiny little region.
![Page 18: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/18.jpg)
The expanding, cooling universe
![Page 19: 3A03 – GR and Cosmology Ralph Pudritz Dept. of Physics & Astronomy McMaster University](https://reader030.vdocuments.site/reader030/viewer/2022032516/56649c7c5503460f949303d1/html5/thumbnails/19.jpg)
THE ORIGINS OF STRUCTRE IN THE UNIVERSE
How did galaxies form?
- Density fluctuations infinitesimal in size, originate from quantum fluctuations in spacetime soon after the Big Bang.
- These are seen in fluctuations in CMBR – baby photo of galaxies!