TUCSON, ARIZONA, USA: HPI note: Here’s a project that will help you evaluate your place in the universe.
The Large Synoptic Survey Telescope (LSST) is a proposed ground-based 8.4-meter, 10 square-degree-field telescope that will provide digital imaging of faint astronomical objects across the entire sky, night after night. In a relentless campaign of 10 to 15 second exposures, LSST will cover the available sky every three nights, opening a movie-like window on objects that change or move on rapid timescales: exploding supernovae, potentially hazardous near-Earth asteroids, and distant Kuiper Belt Objects. It will generate an awesome 30 terabytes of data per night from a three billion-pixel digital camera, producing a vast database of information on the universe which will be made available on-line immediately.
A single ten-second exposure will detect sources at 24th magnitude. At this level of brightness, the most common objects in the sky are not stars but galaxies — 60,000 of them per square degree on the sky. In one pass across the visible sky (14,000 square degrees, or about three nights of observation), LSST will detect and classify 840 million persistent sources. Over time, LSST will survey 30,000 square degrees. By adding together the first five years of data, the all-sky map will reach 27th magnitude, and its database will contain over three billion sources, not counting transient events.
HPI adds: Consider that your closed fist held at arm’s length covers in width about 10 degrees of the sky, which is about 78 square degrees. Each square degree contains 60,000 galaxies bright enough for this telescope to see, so your fist is blocking at least 4.7 million galaxies, each containing ten billion to one trillion stars….