The Hubble Space Telescope can show us galaxies that stretch back in time to the beginning of our Universe and details of astronomical objects that we could not see before. How does it work? Well, it relies on a parabola.
Why It Matters
When you gaze at the stars or planets through a 10-inch telescope, you are seeing more than 1,000 times as much light compared to the light captured by your naked eye. This makes the celestial bodies appear clearer, enabling us to magnify them.
You can see how the telescope achieves this effect in the diagram below. The distant star S shines and its light falls on the parabola-shaped mirror of the telescope, labeled M. Some of the light travels along the line A, some along the line B, etc., but the amazing property of the parabola is that all of the light reflected by the mirror will travel to a single point, F, which is called the focus of the parabola. In a telescope, that is where you want your eye to be!
Below is an image called the “Hubble eXtreme Deep Field” (XDF), which was created in 2012 by combining data from a decade’s worth of Hubble observations of a tiny fraction (one 30-millionth!) of the sky. The image is the “deepest” image of the Universe ever created, and the ten-year exposure revealed 5,500 galaxies—some of which are so far away that we’re seeing them when the Universe was less than 5% of its present age.
Before the XDF, there was the HDF, or the “Hubble Deep Field.” Created in 1995, the HDF was the first image of its kind. One of the most important pictures that man has ever taken, it provided an unprecedented glimpse into the far depths of space and the beginnings of our Universe.
See for yourself: http://www.youtube.com/watch?v=fgg2tpUVbXQ
The mirror of the Hubble Space Telescope has a diameter of 94 inches. It captures nearly 100,000 times as much light as your eye! Learn more about the telescope at the links below.