Astronomers used the Hubble Space Telescope to create the most revealing - and colorful - images of the Universe ever created. The Ultraviolet Coverage of the Hubble Ultra Deep Field (UVUDF) project produced the composite image, providing astronomers with new information concerning stellar formation.
In a rainbow, we see light spread into component colors, from red, through orange and yellow to green, blue and violet. Other "colors" or wavelengths of light exist on either side of what the human eye can detect. Infrared is redder than red, and ultraviolet is just outside visible violet light. Observing astronomical objects in different wavelengths reveals unique information about the bodies.
Researchers can view the birth of stars in nearby galaxies, up to about five billion light-years away. Hubble is also able to watch the same process occur in infrared light, in star formations more than 10 billion years away from Earth. Astronomers had no tools, until now, to witness the phenomenon between those two distances. These events, witnessed on Earth today, occurred between five and ten billion years in the past. It was during this time the Universe experienced the greatest rate of star formation in history, as per cosmologists.
The hottest, most massive and youngest stars in the Universe produce vast quantities of ultraviolet light. By studying images taken in these wavelengths, astronomers are able to detail information about the stellar bodies. Ultraviolet astronomy could also help cosmologists understand how galaxies formed from small collections of ultra-hot stars.
The Hubble Ultra Deep Field images showed thousands of galaxies in just a small patch of sky. This famous composite photo was composed of images taken in visible and infrared light.
Hubble took images of the same region of space in ultraviolet (UV) light. Observations of astronomical bodies made in these wavelengths must be carried out by space-based telescopes, as the atmosphere of the Earth absorbs most ultraviolet light coming from space. Astronomers have now added these UV photos to the composite.
"It's the deepest panchromatic image of the sky ever made. It reaches the faintness of one firefly as seen from the distance of the moon," Rogier Windhorst of the School of Earth and Space Exploration at Arizona State University said.
The raw images that went into this latest design were recorded over 841 orbits of the world's most-famous space-based telescope. Hubble's Advanced Camera for Surveys and Wide Field Camera 3 (WFC3) were used to take the raw images that were used in the composite. The WFC is the latest tool available on Hubble, added to the orbiting observatory in 2009.
Other Hubble Deep Field images have been taken since 1995. Some looked at different portions of the sky than the one lately updated with ultraviolet readings. More than 10,000 galaxies are visible in the new photograph, some of which date back to just a few hundred million years after the Big Bang.