NASA and the European Space Agency this week announced that NASA would be participating in the ESA’s Euclid mission scheduled for launch in 2020. Euclid is a space telescope whose purpose is to investigate cosmic dark matter and dark energy.
The Euclid telescope is designed to maintain a relatively stationary position after launch at a point behind the Earth as seen from the Sun known as the Lagrange point L2 at a distance of 1.5 kilometres from Earth. Euclid’s science and spacecraft operations will be conducted by the ESA, reports the ESA website.
During the spacecraft’s six year mission, it will map and measure up to 2 billion galaxies covering more than 33 percent of the sky. Euclid will also focus on dark matter and dark energy, phenomena still little understood, which are believed to influence how our Universe has evolved and continues to evolve. By peering into parts of the Universe billions of light years away, Euclid will be looking back into the distant past, three quarters of the way back towards the time when our Universe came into existence.
The NASA contribution to Euclid involves NASA supplying 16 infra red detectors and four spare detectors for Euclid’s payload of two scientific instruments which also includes a visible-wavelength camera. NASA will also play a significant role in the Euclid Consortium, an august body of over 1,000 scientists, astronomers, astrophysicists, engineers and others tasked with supporting the Euclid mission, the development of instruments and data analysis. NASA has nominated three US science teams with 40 new members who will join the 14 US scientists already assisting the Euclid Consortium.
Wikimedia Commons - NASA WMAP Science Team
Schematic showing proportions of dark matter/dark energy to physical particles as believed to exist now and at a much earlier time near when the Universe came into existence.
Euclid’s prime purpose is to map dark matter in the Universe. Dark matter is the unseen part of the Universe, making up an estimated 85 percent and consisting of as yet unknown particles. Dark matter cannot be detected by telescopes directly since it neither emits nor absorbs any significant amounts of light or other electromagnetic radiation. The existence of dark matter was first postulated by Jan Oort in 1932 to account for the orbital velocities of stars in the Milky Way and to explain what appeared to be "missing mass" in the orbital velocities of galaxies in clusters. The physical Universe, constituent atoms that make up celestial bodies and everything else that we can actually see, represents a relatively small part of the totality of matter in the Universe.
To find dark matter, the Euclid infra red detectors work on the principle that the existence and properties of this, the Universe’s missing mass, may be inferred from the gravitational effects dark matter has on visible matter, radiation, and large-scale structure of the universe like galaxies. Euclid’s measurements principally involve extremely precise measurements of galaxies billions of light years distant from us. Although dark matter does not interact with light, the gravitational effects of dark matter can be detected as it is through the force of gravity that dark matter binds galaxies together like an invisible glue.
Even more mysterious than dark matter is the less well understood dark energy which Euclid will also investigate. While dark matter acts to pull galaxies together, dark energy is believed to be pushing the Universe apart at an accelerating rate. With the Universe continuing to expand, dark energy currently has the upper hand in its battle of the cosmic forces with dark matter. The concept of cosmic acceleration was discovered by teams of US, European and other international scientists in 1998 and for their work in this field, scientists Saul Perlmutter, Brian P. Schmidt and Adam G. Riess were jointly awarded the Nobel Prize for Physics in 2011 "for the discovery of the accelerating expansion of the Universe through observations of distant supernovae".
Speaking at NASA HQ in Washington, John Grunsfeld, associate administrator for NASA's Science Mission Directorate, said, "NASA is very proud to contribute to ESA's mission to understand one of the greatest science mysteries of our time."
The NASA contribution was welcomed by Alvaro Gimenez, ESA's Director of Science and Robotic Exploration, saying, "ESA's Euclid mission is designed to probe one of the most fundamental questions in modern cosmology, and we welcome NASA's contribution to this important endeavor, the most recent in a long history of cooperation in space science between our two agencies"