HETDEX Impact

HETDEX

HETDEX will be the first major experiment to search for dark energy. It uses the giant Hobby-Eberly Telescope at McDonald Observatory and a set of spectrographs to map the three-dimensional positions of one million galaxies

The subject of this revolution is dark energy, a mysterious force that is causing the universe to expand faster as it ages. And one of the leaders in the revolution is HETDEX — the Hobby-Eberly Telescope Dark Energy Experiment — at The University of Texas at Austin McDonald Observatory. Its observations will narrow the list of possible explanations for dark energy, and may even provide the final answer.

HETDEX will combine the immense light-gathering power of the Hobby-Eberly Telescope, the world’s third largest, with an array of new instruments for analyzing the light from distant galaxies.

During three years of observations, HETDEX will collect data on at least one million galaxies that are 9 billion to 11 billion light-years away, yielding the largest map of the universe ever produced. The map will allow HETDEX astronomers to measure how fast the universe was expanding at different times in its history. Changes in the expansion rate will reveal the role of dark energy at different epochs. Various explanations for dark energy predict different changes in the expansion rate, so by providing exact measurements of the expansion, the HETDEX map will eliminate some of the competing ideas.