Telescopes are time-machines that allow us to see into the distant past. The deepest images we can see in the Universe are not from today, but maybe as much as 400,000 years or more after the Big Bang. And we can see that at that time there were no galaxies, no stars, no planets, no people, no familiar elements other than hydrogen and helium. The cosmos contained nothing but weak sound waves in a near-uniform fog. And although supercomputers can compress thirteen billion years of cosmic evolution into a few months of calculation to show how these sound waves developed into the rich structure we see around us today. A study of their harmonic content gives clues to their origin. They appear to be an echo of quantum zero-point fluctuations occurring a tiny fraction of a second after the Big Bang. Thus our entire world may be a consequence of the nature of this early vacuum. In a very real sense, everything may have come from nothing.
For that reason “astronomy is history” and the Hubble Space Telescope has obtained long-exposure images that reveal the faintest objects ever detected providing our deepest look back into space. An expert explains: “Some of these objects are galaxies seen during their early developmental stages when they were rich in young, hot, and very luminous stars. To peer still farther back through time, to reach the era when stars first began to shine, astronomers need a telescope that can detect extremely low intensities of infrared light. Astronomers need sensitivity in the infrared part of the spectrum because the light from these young stars in distant galaxies, even though emitted as visible light, has been stretched by the expansion of the universe to appear to us as infrared light.
The Hubble Space Telescope can observe the shortest-wavelength portion of the infrared domain, but its 2.4-meter mirror is too warm and too small to detect the faint glow from the most distant young galaxies. To observe galaxies in their earliest epochs, the survey report recommends a new, advanced- technology telescope designed to work best in the infrared part of the spectrum. In an orbit a million miles from Earth, this telescope will become so cold that its own infrared glow will be insignificant compared with the light from the distant galaxies, something an earthbound telescope could never achieve. Also, being above Earth’s veil of air allows us to see radiation that cannot penetrate it, and guarantees the sharpest images the telescope can deliver, free from the turbulence in Earth’s atmosphere that handicaps telescopes on the ground.”
Via: Professor Simon White from Max Planck, Garching, Germany