Jan_17 - The Big Bang Thursday, January 17 Doppler shift...

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
The Big Bang The Big Bang Thursday, January 17
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Doppler shift Doppler shift tells you if an object is coming toward you or moving away. Blueshift: distance decreasing. Redshift: distance increasing.
Background image of page 2
All distant galaxies have redshifts .
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
But wait, there’s more!. ... The amount amount by which the wavelength is shifted tells us the radial velocity radial velocity of the object, in kilometers/second.
Background image of page 4
A light source is at rest: it emits light with a wavelength λ 0 . If distance to light source is changing changing , Doppler shift will change the wavelength to λ ≠ λ 0 .
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Size of Doppler shift is proportional to radial velocity: c V 0 0 = - λ λ = observed wavelength λ 0 = wavelength if source isn’t at rest V = radial velocity of moving source c = speed of light
Background image of page 6
Hydrogen absorbs light with λ 0 = 656.3 nm. You observe a star with a hydrogen absorption line at λ = 656.2 nm. 656.3 nm ↓
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Thinking locally: stars within 3 parsecs of the Sun. Proxima Centauri
Background image of page 8
Equal numbers of redshifts and blueshifts. Typical radial velocity V = 30 km/second (70,000 mph).
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Thinking more globally: galaxies within 30 million parsecs of the Milky Way.
Background image of page 10
redshifts rather than blueshifts . Typical radial velocity
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 07/17/2008 for the course ASTRO 294 taught by Professor Ryden during the Winter '08 term at Ohio State.

Page1 / 36

Jan_17 - The Big Bang Thursday, January 17 Doppler shift...

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online