Scientists are about to get a brand new tool to uncover among the most elusive mysteries of our universe.
The European Space Agency’s Euclid mission, which is about to launch on July 1, is designed to check the so-called “dark universe.” That is how scientists confer with the more mysterious components of the cosmos, namely dark matter and dark energy. To accomplish that, this cutting-edge mission will employ among the principles of geometry laid down by its ancient Greek namesake, the mathematician Euclid of Alexandria.
But who exactly was Euclid, and why is he still so vital?
Related: Euclid mission: ESA’s hunt for dark matter and dark energy
What’s the Euclid mission?
The Euclid spacecraft accommodates a 3.9-foot-wide (1.2 meters) telescope — half the dimensions of the Hubble Space Telescope — that may view the universe in visible and near-infrared light. Unlike Hubble and the James Webb Space Telescope, that are designed with narrow fields of view for close-up, high-resolution work, Euclid is taking a wide-angle approach that may encapsulate 1000’s of distant galaxies at a time.
Its field of view is 0.57 square degrees, which is just lower than twice the diameter of the complete moon. For a telescope, it is a huge expanse of sky to see in a single shot, and it’s going to allow Euclid’s two instruments — its Visible Imager (VIS) and its Near-Infrared Spectrometer and Photometer (NISP) — to probe 1.5 billion distant galaxies in only six years to learn more about dark matter and dark energy. These two mysterious components make up 26.8% and 68.3% of the universe, respectively, but astronomers have no idea what they’re; we only know these dark elements are there due to invisible dark matter’s gravitational effect and the best way dark energy is accelerating the expansion of the universe.
The density of matter and energy within the cosmos determines the geometry of the universe, within the sense that matter and energy can warp space-time, or stretch it. Since dark matter and dark energy make up the overwhelming majority of matter and energy within the universe, it is that they that actually control the universe’s geometry.
Euclid will study these dark influences in two ways. One is to have a look at how galaxies cluster by conducting a survey that catalogs galaxy redshifts to create a three-dimensional map of galaxies stretching across 10 billion light-years. How galaxies are clustered relates back to fluctuations within the density of matter within the cosmic microwave background (CMB), radiation emitted just 279,000 years after the Big Bang that created the universe. Comparing those fluctuations — called baryonic acoustic oscillations (BAOs) — with the dimensions of clusters at later epochs can tell us about how the strength of dark energy has modified over time, because its repulsive force works against the gravity that causes galaxies to cluster.
The opposite way during which Euclid will study the dark universe is by the shapes of galaxies. The gravity from dark matter spread across the universe can create gravitational lenses that bend light. We see this in dramatic fashion within the strong gravitational lenses of galaxy clusters, but dark matter may cause “weak lensing” that subtly distorts the shapes of galaxies by altering the geometry of space and the trail that light takes to succeed in us. Euclid will image 1.5 billion galaxies and search for those shape distortions to permit astronomers to map dark matter within the universe.
Who was Euclid the mathematician?
The mission is called after the daddy of geometry, the ancient Greek mathematician Euclid. (That’s his anglicized name, his Greek name was Eukleides). He lived across the 12 months 300 BCE in the town of Alexandria, which was founded by Alexander the Great in 330 BCE. Nobody is entirely sure of Euclid’s personal details, including when exactly he was born and died. What we do know are what he left us: his great works of mathematics, particularly “Elements,” a treatise on geometry and some of the widely translated books on the earth.
As such, Euclid has turn into often known as the “father of geometry.” Much of what Euclid the space mission will do relies on geometry, and the way gravitational lensing and cosmic expansion alters that geometry.
Particularly, we call Euclid’s particular brand of geometry “Euclidean geometry.” It is the geometry that you just’re taught in class, of flat planes, parallel lines, right angles, trigonometry and the Pythagorean Theorem.
Euclid based his geometry on a foundation of five axioms, or accepted truths. These include the indisputable fact that any two points might be joined by a straight line; straight lines might be prolonged indefinitely; a circle might be drawn by simply knowing where its centre is and the dimensions of its radius; that each one right angles (90 degrees) are equal; and that if a straight line X intersects two other straight lines, Y and Z, and if the angles X makes with Y and Z respectively are lower than 90 degrees, then Y and Z will cross one another if prolonged indefinitely (in other words, forming a triangle).
From this foundation, Euclid was in a position to formulate a geometrical system that we still use 2,300 years later in on a regular basis life. Nevertheless, astronomers are in a position to search for deviations from Euclidean geometry in space, reminiscent of in gravitational lenses, to look for evidence of the dark universe.
Euclid of Alexandria’s legacy will live to tell the tale eternally. He was a genius of his time, dabbling also in perspective geometry, algebra and so-called “spherical astronomy,” which involves a type of geometry for locating objects on the celestial sphere. There’s some evidence suggesting that Euclid was a student of Plato and taught at Alexandria’s Museum, which was home to the famous Library of Alexandria and where he also arrange a famed school of mathematics.
Now, over two millennia later, his legacy will enter the ultimate frontier in our greatest attempt yet to unravel among the most confounding mysteries of our universe.
Additional Resources
You’ll be able to read more concerning the Euclid mission on the website of the Euclid Consortium, the collaboration of institutions and organizations behind the mission to map the dark universe. NASA also has a stake within the mission, having provided the infrared detectors and being involved within the evaluation of the information that Euclid will collect.
Bibliography
— European Space Agency, The Euclid Consortium, Partnerships and Euclid Flagship Mockup Galaxy Catalog: https://www.eoportal.org/satellite-missions/euclid#the-euclid-consortium-partnerships-and-euclid-flagship-mockup-galaxy-catalog
— University of St Andrews, Euclid of Alexandria: https://mathshistory.st-andrews.ac.uk/Biographies/Euclid/
— Mark Cropper et al, VIS: The Visible Imager for Euclid: https://arxiv.org/pdf/1608.08603.pdf
—European Space Agency, Euclid VIS Instrument: https://sci.esa.int/web/euclid/-/euclid-vis-instrument
— European Space Agency, Euclid NISP Instrument: https://sci.esa.int/web/euclid/-/euclid-nisp-instrument
— Chris North, University of Cardiff, the Planck Satellite: Cosmic Microwave Background: https://plancksatellite.org.uk/results/cosmic-microwave-background/
— University of Geneva, Euclid in a Nutshell: Looking Through the Universe: https://www.isdc.unige.ch/euclid/
— European Space Agency: What Are Baryonic Acoustic Oscillations? https://sci.esa.int/web/euclid/-/what-are-baryonic-acoustic-oscillations-
— European Space Agency: What’s Gravitational Lensing https://sci.esa.int/web/euclid/-/what-is-gravitational-lensing
— Bartel Leendert van der Waerden and Christian Marinus Taisbak, Encyclopaedia Britannica, Euclid: https://www.britannica.com/biography/Euclid-Greek-mathematician
— Benjamin Wardhaugh, Princeton University: Who Was Euclid https://press.princeton.edu/ideas/who-was-euclid
— J. L. Heiberg, Richard Fitzpatrick, Euclid’s Elements of Geometry: https://farside.ph.utexas.edu/books/Euclid/Elements.pdf
— John D. Norton, University of Pittsburgh: Euclidean Geometry: The First Great Science: https://sites.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/non_Euclid_Euclid/index.html
— Norman Swartz, Simon Fraser University: Axioms and Postulates of Euclid: https://www.sfu.ca/~swartz/euclid.htm
— Mostafa El-Abbadi, Encyclopaedia Britannica: Library of Alexandria: https://www.britannica.com/topic/Library-of-Alexandria