Cosmic Microwave Background Leans To Inflation Theory

Strigiform writes "Some of the questions about the early universe have been answered by the WMAP project as reported by New Scientist. The inflation theory of the early universe has been vindicated, as it correctly predicted the polarisation of microwaves observed. The earliest stars appeared only 200 million years after the Big Bang and the universe is about 13.7 billion years old"

Comments

Up-to-date tutorials on CMB

[RobotWisdom]

The AstroPic of the Day this morning includes links to Wayne Hu's accessible tutorials on the CMB: beginners (12pp) and intermediate (much longer, I think).

Short version, as best I've understood so far:

During the earliest expansion after the Big Bang, the attraction of gravity was counterbalanced by the pressure of photons, with slight fluctuations that echoed thru this superdense plasma as 'sound'.

The resonant frequency of the sound was limited by the speed of gravity (ie, speed of light) and the spatial 'horizon' it could reach over the course of the universe's short life. (Harmonics also arose at some point.)

When the plasma cooled enough for atoms to form, all the photons were released at once, in a pattern that retained the resonant-frequencies fluctuations, and that's what WMAP is measuring.

Re:Q. Spherical expansion & Planet's Orbits

[KDan]

Q1: It does, but it's a 4-dimensional sphere... little or nothing to do with a 3D sphere.

Q2: The planets formed from a great big cloud of gas (a protostar) which also formed the sun. After the sun started 'emitting', there was still some leftovers. They turned into the planets. Now due to the facts that a) there's some residual magnetic field lines due to some other objects around the condensing protostar and b) it's easier to move without crossing magnetic field lines than to cross them (ie costs less energy) the circular motion in the direction that crosses field lines died down whereas the motion in the direction that doesn't cross field lines stayed. So that turned a ball of gas into a flattened disc of gas. Then the planets formed. That's why they're all in the same plane, more or less. See "Thin Accretion Discs" in your favourite physics library for more advanced info.

Daniel