The dark-energy mapper is ready to probe mysteries
The Euclid Telescope: Space Launch for a New Probe of the Cosmic Intergalactic Medium (Extended Abstract)
A new space probe is set to launch Saturday morning and it has the power to shed light on the biggest questions in the universe. If all goes as planned, the Euclid telescope will scan billions of galaxies, poring through the past 10 billion years of cosmic time. It will give scientists the data they need to better understand dark matter and dark energy.
After more than a decade of hard work, the European Space Agency, or ESA, is planning for liftoff at 11:11 Eastern time on July 1 from Cape Canaveral, Florida. A rocket is going to give the ride to space. (The agency will broadcast the launch live here, and they’re reserving Sunday as a backup launch date.)
Using Weak Lensing to Determine the Cosmic Gravitational Constant as Seen by two Telescopes at the Euclid Observatory
Laureijs and his colleagues want to find out the ratio of the universe’s dark energy to its density. Einstein hypothesized a “cosmological constant,” or the notion that the universe is filled with empty space, which nonetheless has its own energy and couples to gravity. The negative of the energy density should be equal to the pressure of dark energy. In other words, if dark energy is the cosmological constant, then w should equal -1.
It is possible that this is the case, but studies with previous telescopes have large uncertainties in their measurement. By analyzing the data from Euclid, we can see if a constant is the correct explanation for the universes acceleration. It will show whether w has changed during the course of history.
The telescope will watch the sky with two cameras simultaneously: one in the visible spectrum and the other in the infrared whileollowing Earth’s orbit around the Sun from a distance of 1.5 million kilometres
The two cameras were originally created as separate proposals, but the teams were asked to join together in a single mission. The solution was to use a dichroic plate, or mirror, which is transparent to everyone but the visible and invisible wavelengths, to bring light to both cameras at once.
“All of these surveys will be very interesting by themselves – and more interesting things together,” says Jo Dunkley, an astronomer with the University of New Jersey. The data will be combined to extract the large-scale properties of the Universe.
Two types of analysis will be fed by the data from the cameras. Computer code will comb through the visible-light pictures to look for subtle distortions that typically squeeze the apparent shapes of galaxies by less than 1% in one direction or another. The distortions reveal the presence of huge mass in the foreground that curves space and bends the light from objects in the background.
“This weak lensing effect is everywhere in the sky,” says Anthony Tyson, an astronomer at the University of California, Davis, who pioneered the technique beginning in the 1980s and then helped to spearhead the Vera Rubin Observatory.
The gravitational lensing will allow cosmologists to measure whether the dark-matter scaffolding is thin and dense or more puffed up, which in turn could provide clues to the nature of the elementary particles that constitute the dark matter, says Dunkley. It will also provide a way to measure the mass of subatomic particles called neutrinos, because the lighter they are, the farther they fly out of galaxies and the more they contribute to the puffing up.
Launching of Euclid on a Russian Soyuz rocket in Kourou, Guiana, in response to the Russian invasion of Ukraine
Euclid was originally scheduled to launch on a Russian Soyuz rocket from the European spaceport in Kourou, French Guiana. The mission was put in a dire situation by the invasion of Ukraine by Russia, according to Giuseppe Racca, the mission manager. “We were faced with possibility of putting the spacecraft in storage and launching in three to four years.” The team was relieved to find out that the spacecraft was compatible with a Falcon 9 launch.
