On Saturday, July 1st (Canada Day!), ESA’s Euclid Space Telescope lifted off from Cape Canaveral, Florida. This next-generation astrophysics mission will fly to the Earth-Sun L2 Lagrange point over the next few weeks, observing a third of the sky there over the next six years. During that time, Euclid will observe billions of galaxies 10 billion light-years away, creating the most comprehensive 3D map of the Universe ever made. This map will help astronomers and cosmologists solve the remaining mystery of Dark Matter and Dark Energy (DM & DE).
The mission launched at 11:12 a.m. EST (8:12 a.m. PST) on a SpaceX Falcon 9 rocket, with the second stage separating approximately 2 minutes and 45 seconds later. After about 3 minutes and 37 seconds, the payload fairings detached. Forty-five minutes after launch, ground controllers received confirmation that Euclid had separated from the second stage and made it to Low Earth Orbit (LEO). Over the next two weeks, Euclid will deploy its sunshade and reach operating temperature before departing for L2 on July 29 (four weeks after launch).
ESA’s Euclid mission lifts off from Cape Canaveral on July 1, 2023. Photo credit: ESA
Using its 600-megapixel camera, near-infrared spectrometer, and photometer (which measures the redshift of galaxies), Euclid will record how the Universe has expanded over the past 10 billion years (~3 billion years since the Big Bang) to the present day. This coincides with the beginning of the “Dark Energy Dominated Era” when the universe began to gradually expand at an accelerating rate. By mapping the large-scale cosmic structure of the universe and how it has changed since then, Euclid will reveal more about the role of gravity, dark matter and dark energy in space and time.
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Understanding how these forces interact is critical to solving the current “crisis of cosmology.” These include the rotation curves of galaxies and the fact that these do not correspond to the amount of visible (“luminous”) matter they contain. Scientists noticed this in the 1960s, leading to the theory that 85% of a galaxy’s mass is made up of some mysterious, invisible matter (hence the term “dark”). Speculations about the existence of dark energy began in the 1990s, largely thanks to Hubble and his Deep Fields campaigns.
As scientists looked further into the cosmos (and thus into the past), they found that cosmic expansion has accelerated over the past four billion years. This, combined with the unsolved mystery of dark matter, suggested that either our theories of gravity (as described in general relativity) are wrong, or that an unknown force is responsible for counteracting gravity on the largest scales. Based on the most widely used cosmological model – the Lambda Cold Dark Matter (LCDM) model – cosmologists estimate that dark energy accounts for about 72% of the mass-energy density of the universe.
By measuring the influence of dark matter and dark energy, Euclid will help end the ongoing debate about prevailing cosmological theories. Once Euclid reaches L2, where it will join the James Webb Space Telescope (JWST), mission leaders will begin checking all spacecraft functions, testing the telescope and finally turning on the instruments. This will be followed by a two-month period during which they will test and calibrate each of Euclid’s scientific instruments and prepare for the telescope’s first observations. Three months after launch, mission leaders will begin the early phase of Euclid’s cosmic survey.
By 2027, it will be joined by the Nancy Grace Roman Space Telescope (RST), which will help in the search for dark energy by providing more detailed analysis of objects mapped by Euclid. Check out the launch summary below, courtesy of ESA:
Further reading: ESA