Skip to main content

Cosmology A Research Briefing (1995) / Chapter Skim
Currently Skimming:

II. THE COSMIC MICROWAVE BACKGROUND RADIATION
Pages 13-18

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 13...
... Cosmological theories based on the Big Bang unambiguously predict that the temperature of the universe will fall with time as the universe expands. Recent observations from the new Keck telescope have provided the first direct evidence that the CMBR temperature has indeed decreased over (relatively recent)
Read the entire page →
From page 14...
... Recently, data from an independent balloon experiment, using a frequency above that of the COBE's receivers, exhibited the r same basic CMBR pattern as seen in the COBE data, thus confirming the satellite result. Lowcost balloon experiments have also enabled important first steps toward extending these results to smaller angular scales.
Read the entire page →
From page 15...
... Techniques for successful experiments are being developed using the experience gained with suborbital experiments, but Earth's environment poses major problems for experiments requiring high accuracy and large sky coverage. Research now under way will ultimately lead to the design of a satellite that can utilize the advantages of the space environment.
Read the entire page →
From page 16...
... However, variants of the Big Bang theory, such as theories involving cosmic strings (discontinuities in the structure of space) , predict that important clues to the universe's history might be embedded in the CMBR at these angular scales.
Read the entire page →
From page 17...
... This combination of observations gives us a powerful probe of Big Bang density fluctuations over a wide range of scales. The extent of early density fluctuations on different size scales and their subsequent growth under gravity are critical clues to the nature and amount of dark matter in the universe, as explained below.
Read the entire page →
From page 18...
... Deeper surveys of the whole sky in visible light are being conducted using highly sensitive detectors (called charge-coupled devices; CCDs) that can detect intrinsically faint galaxies, galaxies of low surface brightness, and distant galaxies.
Read the entire page →

Key Terms

  • big bang
  • angular scales
  • cmbr spectrum
  • dark matter
  • anisotropy measurements

  • gravitational instability
  • sky coverage
  • gravitational lenses
  • bump size
  • bang theory

  • balloon experiments
  • experience gained
  • anisotropy signal
  • cobe anisotropy
  • visible light

  • density fluctuations
  • expansion rate
  • clustering behavior
  • sky pattern
  • remarkable pattern

  • distant galaxies
  • theories involving
  • direct comparison
  • receding source
  • intrinsically faint

  • hot gas
  • scientific results
  • groundbased experiments
  • space environment
  • recently discovered


    • This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
    More information on Chapter Skim is available.