Starship Asterisk*

alec schuetter wrote:looking at this picture (march 9,) i am thinking that we are moving in a specific direction; does anybody know which?

Arramon wrote:the shape is due to the orbit of the satellite plus the shifting explained, no? and the 'black dots' are from the dipole subtraction...?

The Far-Infrared Absolute Spectrophotometer (FIRAS) instrument on the Cosmic Background Explorer (COBE) has determined the dipole spectrum of the cosmic microwave background radiation (CMBR) from 2 to 20/cm. For each frequency the signal is decomposed by fitting to a monopole, a dipole, and a Galactic template for approximately 60% of the sky. The overall dipole spectrum fits the derivative of a Planck function with an amplitude of 3.343 +/- 0.016 mK (95% confidence level), a temperature of 2.714 +/- 0.022 K (95% confidence level), and an rms deviation of 6 x 10-9 ergs/sq cm/s/sr cm limited by a detector and cosmic-ray noise. The monopole temperature is consistent with that determined by direct measurement in the accompanying article by Mather et al.

The DMR was able to spend four years mapping the anisotropy of cosmic background radiation as it was the only instrument not dependent on the dewar’s supply of helium to keep it cooled. This operation was able to create full maps of the CMB by subtracting out galactic emissions and dipole at various frequencies. The cosmic microwave background fluctuations are extremely faint, only one part in 100,000 compared to the 2.73 kelvin average temperature of the radiation field. The cosmic microwave background radiation is a remnant of the Big Bang and the fluctuations are the imprint of density contrast in the early universe. The density ripples are believed to have produced structure formation as observed in the universe today: clusters of galaxies and vast regions devoid of galaxies (NASA).

neufer wrote:If the APOD had been done to a resolution that the captions were legible I would have done so.
Besides, IMHO this beautiful map (unlike the simple Dipole IR map) cannot be displayed enough.

bystander wrote:Neufer: It is enough that you post the links. We can go to the picture ourselves. Including these large images messes with the side to side scrolling. Just a suggestion, not a rant.

Ren Laoshi wrote:The yin-yang shape is immediately apparent, but why does it look that way? There are probably many places that explain this, but I don't know them. I'm guessing this "dipole" image represents a spherical depiction of the CMBR reduced to a 2D circle. If so, then I can easily imagine a blue and red hemisphere, appropriately hubble-shifted. But then why are there the spots? Are these artefacts of removing galaxy interference (as in Milky Way)?

ta152h0 wrote:http://antwrp.gsfc.nasa.gov/cgi-bin/apo ... MBR+Dipole

are these the same images ?

cherlin wrote:I find it amusing that we can now tell how fast the earth is moving relative to the cosmos, when Relativity was born from the failure of attempts at just that over a century ago.

Of course, Michelson and Morley were trying to measure the relative speed of light, in order to find our speed relative to the then supposed Luminiferous Ether, Without their exquisitely sensitive interferometers, we couldn't have discovered that C is constant for all observers.

These days, we instead measure the relative energy (or equivalently wavelength) of red-shifted and blue-shifted cosmic microwaves, and use many times more sensitive interferometers to look for gravity-wave bursts. I'm running Einstein@Home right now.