{"id":59191,"date":"2024-05-23T10:12:41","date_gmt":"2024-05-23T10:12:41","guid":{"rendered":"http:\/\/21ed8f15-5555-475f-b681-c5879a2ff1e9"},"modified":"2024-05-23T11:08:24","modified_gmt":"2024-05-23T11:08:24","slug":"the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies\/","title":{"rendered":"The Euclid mission will study the mysteries of the dark Universe by mapping 2 billion galaxies"},"content":{"rendered":"

The new European space telescope will tackle the mysteries of dark matter and dark energy. <\/p>

By <\/p>

Published: Thursday, 23 May 2024 at 10:12 AM<\/p>

\n\n

Look at the numerous eye-catching images of space available online and marvel at the beauty of the cosmos.<\/p>

Then realise that everything we can see with astronomical telescopes \u2013 stars<\/a>, nebulae<\/a>, galaxies<\/a> \u2013 amounts to a mere 5% of the total content of the Universe.<\/p>

The remaining 95% is composed of two mysterious components: dark energy<\/a> \u2013 the \u2018force\u2019 behind the accelerating expansion of the Universe<\/a> \u2013 and dark matter<\/a>.<\/p>

We know they exist, but their true nature eludes us.<\/p>

A dark matter halo mapped in galaxy Abell 1689. Credit: NASA, ESA, E. Jullo (Jet Propulsion Laboratory), P. Natarajan (Yale University), and J.-P. Kneib (Laboratoire d’Astrophysique de Marseille, CNRS, France); Acknowledgment: H. Ford and N. Benetiz (Johns Hopkins University), and T. Broadhurst (Tel Aviv University)<\/figcaption><\/figure>
**What Euclid will do<\/strong><\/h2>**Enter Euclid<\/a>, the next space mission in the Cosmic Vision science programme of the European Space Agency (ESA).<\/p>
The Euclid mission launched on 1 July 2023<\/a> from Cape Canaveral in Florida.<\/p>
This ambitious space telescope will focus on the dark Universe by mapping and studying no less than two billion galaxies.<\/p>
Routine science observations are due to begin in early 2024, and Euclid will gather data over 6 years, which will be released in yearly data-releases.<\/p>
“Nothing like this has ever been done before,” says Euclid\u2019s independent legacy scientist Ivan Baldry of Liverpool John Moores University<\/a>.<\/p>
Euclid\u2019s observations will reveal the expansion history of our Universe (which is governed by dark energy) and the three-dimensional distribution of mass (which mainly consists of dark matter).<\/p>
As a bonus, the mission will check whether Albert Einstein\u2019s general theory of relativity is the right formulation of gravity<\/a> on cosmic scales.<\/p>
According to project manager Giuseppe Racca at ESTEC<\/a> (ESA\u2019s science and technology centre in Noordwijk, the Netherlands), “This combination is the unique selling point of Euclid.”<\/p>
$\"Like$
Like the James Webb Space Telescope, Euclid will conduct its science from Lagrange point L2, 1.5 million kilometres out from Earth.<\/figcaption><\/figure>
Launching the Euclid mission<\/b><\/h2>
The Euclid mission was selected in 2011 and formally adopted by ESA in the summer of 2012.<\/p>
NASA became a partner in the project in early 2013.<\/p>
At present, the Euclid consortium has about 2,000 members from 13 European countries plus the United States.<\/p>
The original plan was to launch the spacecraft from French Guiana on a Russian Soyuz rocket<\/a> in late 2022, but after Russia invaded Ukraine, cooperation between ESA and the Russian space agency Roscosmos was suspended, and Euclid found itself in need of an alternative launcher.<\/p>
$\"ESA\u2019s$
ESA\u2019s Euclid spacecraft arrived at Port Canaveral in Florida on 30 April 2023. Credit: Thales Alenia Space \/ ImagIn<\/figcaption><\/figure>
Before long, given the repeated delays of the ongoing development of the European Ariane 6, the choice fell on the commercial Falcon 9 rocket of Elon Musk\u2019s SpaceX.<\/p>
“We had to get used to a whole different working environment,” says Racca.”At SpaceX, I hardly met anyone who was older than my own children,” he quips.<\/p>
Meetings were held without detailed minutes being kept. Changes in the launch strategy to accommodate the relatively low mass of Euclid were made almost overnight. But it all went very smoothly and fast.<\/p>
“Yes, I\u2019ve been worried,” Racca admits, “but I\u2019m confident nevertheless. After all, the Falcon 9 has only had two failures on more than 200 launches.”<\/p>
$\"In$
In the pipeline since 2011, Euclid was delayed by the war in Ukraine and will now launch on a SpaceX Falcon 9. Copyright: ESA\u2013S. Corvaja<\/figcaption><\/figure>
Euclid mission’s stats and figures<\/strong><\/h2>
The Euclid spacecraft was constructed by Thales Alenia Space in Italy. Measuring 4.5 metres tall and 3.1 metres in diameter, the launch mass is about two tonnes.<\/p>
Euclid’s payload module, built by Airbus Defence and Space in France, consists of a 1.2-metre telescope (with an optical quality superior to anything like it, according to Racca) and two scientific instruments:<\/p>
A camera operating at visible wavelengths (VIS)<\/li>
A near-infrared spectrometer and photometer (NISP)<\/li><\/ul>
During the six-year mission, the 600-megapixel VIS camera will capture Hubble-quality images of one-third of the sky, with a field of view of half a square degree: about twice the apparent size of the full Moon.<\/p>
Meanwhile, NISP will measure the brightness and the accurate shape of about 1.5 billion galaxies in three near-infrared wavelength bands, and take detailed spectra of some 25 million bright galaxies.<\/p>
After launch, Euclid will take about a month to reach its halo orbit around the second Lagrange point, 1.5 million kilometres beyond Earth as seen from the Sun, in the same region of space as the James Webb Space Telescope.<\/p>
Once per day it will transmit up to 850 gigabits of data to ESA ground stations in Argentina and Spain.<\/p>
$\"The$
The visible-wavelength VIS instrument (covered in black insulation) and near-infrared NISP (wrapped in gold insulation). Credit: Airbus<\/figcaption><\/figure>
Making a 3D inventory of space<\/b><\/h2>
Like a cosmic version of Google Maps, Euclid will provide astronomers with the most comprehensive three-dimensional inventory of the Universe ever.<\/p>
What ESA\u2019s Gaia mission<\/a> (launched in 2013) did for the majority of stars in our Milky Way Galaxy, Euclid will do for a huge number of galaxies in the wider Universe: precisely determine their position on the sky, their shape and their distance.<\/p>
How will it do this? Well, a galaxy\u2019s distance follows from its so-called redshift<\/a>: the longer the light from a galaxy has travelled through expanding space to reach our telescopes, the further the light waves are stretched to longer wavelengths, corresponding to a redder colour.<\/p>
$\"A$
A NASA image showing how wavelengths of light are stretched – or redshifted – as the Universe expands. Credit: NASA\/JPL-Caltech\/\/R. Hurt (Caltech-IPAC)<\/figcaption><\/figure>
For the 25 million brightest galaxies observed by Euclid, the redshifts can be directly measured from the spectra obtained by NISP.<\/p>
For 1.5 billion fainter and more distant galaxies, for which no detailed spectra are available, Euclid\u2019s near-infrared measurements are combined with at least four brightness measurements at various optical wavelengths, obtained by existing large ground-based telescopes such as the Canada-France-Hawaii Telescope<\/a>, Subaru Telescope<\/a> and Pan-STARRS<\/a> (all in Hawaii), and by the future Vera Rubin Observatory in Chile.<\/p>
From the resulting spectral energy distribution, astronomers can deduce a photometric redshift, albeit less precise than NISP\u2019s results.<\/p>
$\"Gaia's$
Gaia’s all-sky view of the Milky Way based on the measurements of almost 1.7 billion stars. Credit: ESA – ESA\/Gaia\/DPAC, CC BY-SA 3.0 IGO<\/figcaption><\/figure>
As Euclid\u2019s project scientist Ren\u00e9 Laureijs at ESTEC explains, mapping the three-dimensional distribution of galaxies at different redshifts sheds light on the cosmic expansion history.<\/p>
After all, the current large-scale structure of the Universe evolved from primordial density perturbations a few hundred thousand years after the Big Bang<\/a>, which have been mapped in detail by ESA\u2019s Planck mission (2009\u20132013).<\/p>
“With Euclid,” says Laureijs, “we will basically create 12 \u2018Planck maps\u2019 for various cosmic epochs, by looking at slices of our 3D galaxy map at various redshifts, corresponding to different lookback times.”<\/p>
Measuring how the large-scale distribution of galaxies has changed over time will tell astronomers if and how dark energy has also evolved.<\/p>
“It\u2019s really the first time we\u2019re doing this,” says Laureijs.<\/p>
$\"The$
The vast area Euclid will survey (blue) and the regions that will get special treatment (yellow). Credit: ESA\/Gaia\/DPAC; Euclid Consortium. Acknowledgment: Euclid Consortium Survey Group<\/figcaption><\/figure>
Euclid mission and gravitational lensing<\/b><\/h2>
Of course, to study the role of dark energy in this way, you have to take the existence and spatial distribution of dark matter into account too.<\/p>
That\u2019s where the razor-sharp images of the VIS instrument come in.<\/p>
Dark matter doesn\u2019t emit any form of radiation, but it betrays its presence by slightly distorting the shapes of background galaxies in a process known as weak gravitational lensing<\/a>.<\/p>
According to Albert Einstein\u2019s general theory of relativity, light is bent by concentrations of mass, whether visible or dark.<\/p>
In other words: a concentration of mass will reveal itself through weak lensing.<\/p>
$\"The$
The swirls of light surrounding giant galaxy cluster Abell 383 at the centre of this image show gravitational lensing in action: the effects of massive objects on space-time.Credit: NASA, ESA, J. Richard (CRAL) and J.-P. Kneib (LAM). Acknowledgement: Marc Postman (STScI)<\/figcaption><\/figure>
Thus, a statistical analysis of the shapes of millions of background galaxies at various cosmological distances makes it possible to reconstruct three-dimensional maps of the mass distribution in the Universe.<\/p>
In studying weak lensing, the Euclid mission will in fact map local deviations from the average large-scale geometry of the Universe, so it\u2019s quite appropriate that the mission has been named after Euclid of Alexandria, the \u2018father\u2019 of geometry, who lived in the third century BC.<\/p>
In addition to mapping the distribution of dark matter and revealing the expansion history of the Universe, Euclid will also measure a parameter known as gamma, which describes the growth of structures like clusters of galaxies.<\/p>
If this parameter doesn\u2019t match predictions from general relativity, that would support alternative theories of gravity, like Modified Newtonian Dynamics (MOND).<\/p>
$\"We$
We can only see dark matter from its effect on stars and galaxies. Here, astronomers used the images of galaxies distorted by gravitational lensing to map out the dark matter, shown in blue. Credit: NASA, ESA, M. Jee and H. Ford (Johns Hopkins University)<\/figcaption><\/figure>
Euclid mission’s other science goals<\/strong><\/h2>
Studying the wealth of imaging data from both of Euclid\u2019s instruments may also reveal huge numbers of brown dwarf stars, as well as low-surface-brightness galaxies.<\/p>
Both may be much more numerous than presently known.<\/p>
Many additional discoveries are expected from the three or four \u2018Euclid Deep Fields\u2019 (adding up to more than 50 square degrees), areas that will be repeatedly imaged by Euclid at hundreds of times more sensitivity than the main survey.<\/p>
“This high-fidelity imaging of one-third of the whole sky at optical and near-infrared wavelengths is completely new territory,” says Baldry.<\/p>
“The archived data will be used by many scientists in years to come and will have a lot of legacy impact.”<\/p>
<\/div><\/figure><p class=\"p6\">No one knows for sure whether or not Euclid will really be able to figure out the true nature of dark matter and dark energy, although astronomers will certainly learn more about their spatial distribution and behaviour over time.<\/p><p class=\"p6\">“It also depends on what exactly you mean by \u2018the nature of\u2019,” says Racca.<\/p><p class=\"p6\">But even if these puzzling cosmic components remain enigmatic, Euclid\u2019s six-year mission will revolutionise our detailed knowledge of the Universe.<\/p><p class=\"p6\">As for eye-catching photographs: dark matter can\u2019t be seen and dark energy can\u2019t be imaged, but Euclid will capture absolutely stunning pictures of the Universe, with almost the same resolution as <a href=\"https:\/\/www.skyatnightmagazine.com\/space-science\/hubble-space-telescope-facts-history\/\">Hubble Space Telescope<\/a> images (one-tenth of an arcsecond), but with a much wider field of view.<\/p><p class=\"p6\">Before the end of the year, they will probably grace the pages of this very website. Stay tuned!<\/p><p><em><strong>This article originally appeared in the July 2023 issue of BBC Sky at Night Magazine.<\/strong><\/em><\/p> <\/body><\/html>\n<hr class=\"no-tts wp-block-separator\"\/>","protected":false},"excerpt":{"rendered":"<p>The new European space telescope will tackle the mysteries of dark matter and dark energy. <\/p>\n","protected":false},"author":24,"featured_media":59192,"template":"","categories":[1],"acf":{"readingTimeMinutes":"9"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies.jpg",1200,800,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies-300x200.jpg",300,200,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies-768x512.jpg",768,512,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies-1024x683.jpg",800,534,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies.jpg",1200,800,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies.jpg",1200,800,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"The new European space telescope will tackle the mysteries of dark matter and dark energy.","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/59191"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/59192"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=59191"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=59191"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

A dark matter halo mapped in galaxy Abell 1689. Credit: NASA, ESA, E. Jullo (Jet Propulsion Laboratory), P. Natarajan (Yale University), and J.-P. Kneib (Laboratoire d’Astrophysique de Marseille, CNRS, France); Acknowledgment: H. Ford and N. Benetiz (Johns Hopkins University), and T. Broadhurst (Tel Aviv University)<\/figcaption><\/figure>
**What Euclid will do<\/strong><\/h2>**Enter Euclid<\/a>, the next space mission in the Cosmic Vision science programme of the European Space Agency (ESA).<\/p>
The Euclid mission launched on 1 July 2023<\/a> from Cape Canaveral in Florida.<\/p>
This ambitious space telescope will focus on the dark Universe by mapping and studying no less than two billion galaxies.<\/p>
Routine science observations are due to begin in early 2024, and Euclid will gather data over 6 years, which will be released in yearly data-releases.<\/p>
“Nothing like this has ever been done before,” says Euclid\u2019s independent legacy scientist Ivan Baldry of Liverpool John Moores University<\/a>.<\/p>
Euclid\u2019s observations will reveal the expansion history of our Universe (which is governed by dark energy) and the three-dimensional distribution of mass (which mainly consists of dark matter).<\/p>
As a bonus, the mission will check whether Albert Einstein\u2019s general theory of relativity is the right formulation of gravity<\/a> on cosmic scales.<\/p>
According to project manager Giuseppe Racca at ESTEC<\/a> (ESA\u2019s science and technology centre in Noordwijk, the Netherlands), “This combination is the unique selling point of Euclid.”<\/p>
$\"Like$
Like the James Webb Space Telescope, Euclid will conduct its science from Lagrange point L2, 1.5 million kilometres out from Earth.<\/figcaption><\/figure>
Launching the Euclid mission<\/b><\/h2>
The Euclid mission was selected in 2011 and formally adopted by ESA in the summer of 2012.<\/p>
NASA became a partner in the project in early 2013.<\/p>
At present, the Euclid consortium has about 2,000 members from 13 European countries plus the United States.<\/p>
The original plan was to launch the spacecraft from French Guiana on a Russian Soyuz rocket<\/a> in late 2022, but after Russia invaded Ukraine, cooperation between ESA and the Russian space agency Roscosmos was suspended, and Euclid found itself in need of an alternative launcher.<\/p>
$\"ESA\u2019s$
ESA\u2019s Euclid spacecraft arrived at Port Canaveral in Florida on 30 April 2023. Credit: Thales Alenia Space \/ ImagIn<\/figcaption><\/figure>
Before long, given the repeated delays of the ongoing development of the European Ariane 6, the choice fell on the commercial Falcon 9 rocket of Elon Musk\u2019s SpaceX.<\/p>
“We had to get used to a whole different working environment,” says Racca.”At SpaceX, I hardly met anyone who was older than my own children,” he quips.<\/p>
Meetings were held without detailed minutes being kept. Changes in the launch strategy to accommodate the relatively low mass of Euclid were made almost overnight. But it all went very smoothly and fast.<\/p>
“Yes, I\u2019ve been worried,” Racca admits, “but I\u2019m confident nevertheless. After all, the Falcon 9 has only had two failures on more than 200 launches.”<\/p>
$\"In$
In the pipeline since 2011, Euclid was delayed by the war in Ukraine and will now launch on a SpaceX Falcon 9. Copyright: ESA\u2013S. Corvaja<\/figcaption><\/figure>
Euclid mission’s stats and figures<\/strong><\/h2>
The Euclid spacecraft was constructed by Thales Alenia Space in Italy. Measuring 4.5 metres tall and 3.1 metres in diameter, the launch mass is about two tonnes.<\/p>
Euclid’s payload module, built by Airbus Defence and Space in France, consists of a 1.2-metre telescope (with an optical quality superior to anything like it, according to Racca) and two scientific instruments:<\/p>
A camera operating at visible wavelengths (VIS)<\/li>
A near-infrared spectrometer and photometer (NISP)<\/li><\/ul>
During the six-year mission, the 600-megapixel VIS camera will capture Hubble-quality images of one-third of the sky, with a field of view of half a square degree: about twice the apparent size of the full Moon.<\/p>
Meanwhile, NISP will measure the brightness and the accurate shape of about 1.5 billion galaxies in three near-infrared wavelength bands, and take detailed spectra of some 25 million bright galaxies.<\/p>
After launch, Euclid will take about a month to reach its halo orbit around the second Lagrange point, 1.5 million kilometres beyond Earth as seen from the Sun, in the same region of space as the James Webb Space Telescope.<\/p>
Once per day it will transmit up to 850 gigabits of data to ESA ground stations in Argentina and Spain.<\/p>
$\"The$
The visible-wavelength VIS instrument (covered in black insulation) and near-infrared NISP (wrapped in gold insulation). Credit: Airbus<\/figcaption><\/figure>
Making a 3D inventory of space<\/b><\/h2>
Like a cosmic version of Google Maps, Euclid will provide astronomers with the most comprehensive three-dimensional inventory of the Universe ever.<\/p>
What ESA\u2019s Gaia mission<\/a> (launched in 2013) did for the majority of stars in our Milky Way Galaxy, Euclid will do for a huge number of galaxies in the wider Universe: precisely determine their position on the sky, their shape and their distance.<\/p>
How will it do this? Well, a galaxy\u2019s distance follows from its so-called redshift<\/a>: the longer the light from a galaxy has travelled through expanding space to reach our telescopes, the further the light waves are stretched to longer wavelengths, corresponding to a redder colour.<\/p>
$\"A$
A NASA image showing how wavelengths of light are stretched – or redshifted – as the Universe expands. Credit: NASA\/JPL-Caltech\/\/R. Hurt (Caltech-IPAC)<\/figcaption><\/figure>
For the 25 million brightest galaxies observed by Euclid, the redshifts can be directly measured from the spectra obtained by NISP.<\/p>
For 1.5 billion fainter and more distant galaxies, for which no detailed spectra are available, Euclid\u2019s near-infrared measurements are combined with at least four brightness measurements at various optical wavelengths, obtained by existing large ground-based telescopes such as the Canada-France-Hawaii Telescope<\/a>, Subaru Telescope<\/a> and Pan-STARRS<\/a> (all in Hawaii), and by the future Vera Rubin Observatory in Chile.<\/p>
From the resulting spectral energy distribution, astronomers can deduce a photometric redshift, albeit less precise than NISP\u2019s results.<\/p>
$\"Gaia's$
Gaia’s all-sky view of the Milky Way based on the measurements of almost 1.7 billion stars. Credit: ESA – ESA\/Gaia\/DPAC, CC BY-SA 3.0 IGO<\/figcaption><\/figure>
As Euclid\u2019s project scientist Ren\u00e9 Laureijs at ESTEC explains, mapping the three-dimensional distribution of galaxies at different redshifts sheds light on the cosmic expansion history.<\/p>
After all, the current large-scale structure of the Universe evolved from primordial density perturbations a few hundred thousand years after the Big Bang<\/a>, which have been mapped in detail by ESA\u2019s Planck mission (2009\u20132013).<\/p>
“With Euclid,” says Laureijs, “we will basically create 12 \u2018Planck maps\u2019 for various cosmic epochs, by looking at slices of our 3D galaxy map at various redshifts, corresponding to different lookback times.”<\/p>
Measuring how the large-scale distribution of galaxies has changed over time will tell astronomers if and how dark energy has also evolved.<\/p>
“It\u2019s really the first time we\u2019re doing this,” says Laureijs.<\/p>
$\"The$
The vast area Euclid will survey (blue) and the regions that will get special treatment (yellow). Credit: ESA\/Gaia\/DPAC; Euclid Consortium. Acknowledgment: Euclid Consortium Survey Group<\/figcaption><\/figure>
Euclid mission and gravitational lensing<\/b><\/h2>
Of course, to study the role of dark energy in this way, you have to take the existence and spatial distribution of dark matter into account too.<\/p>
That\u2019s where the razor-sharp images of the VIS instrument come in.<\/p>
Dark matter doesn\u2019t emit any form of radiation, but it betrays its presence by slightly distorting the shapes of background galaxies in a process known as weak gravitational lensing<\/a>.<\/p>
According to Albert Einstein\u2019s general theory of relativity, light is bent by concentrations of mass, whether visible or dark.<\/p>
In other words: a concentration of mass will reveal itself through weak lensing.<\/p>
$\"The$
The swirls of light surrounding giant galaxy cluster Abell 383 at the centre of this image show gravitational lensing in action: the effects of massive objects on space-time.Credit: NASA, ESA, J. Richard (CRAL) and J.-P. Kneib (LAM). Acknowledgement: Marc Postman (STScI)<\/figcaption><\/figure>
Thus, a statistical analysis of the shapes of millions of background galaxies at various cosmological distances makes it possible to reconstruct three-dimensional maps of the mass distribution in the Universe.<\/p>
In studying weak lensing, the Euclid mission will in fact map local deviations from the average large-scale geometry of the Universe, so it\u2019s quite appropriate that the mission has been named after Euclid of Alexandria, the \u2018father\u2019 of geometry, who lived in the third century BC.<\/p>
In addition to mapping the distribution of dark matter and revealing the expansion history of the Universe, Euclid will also measure a parameter known as gamma, which describes the growth of structures like clusters of galaxies.<\/p>
If this parameter doesn\u2019t match predictions from general relativity, that would support alternative theories of gravity, like Modified Newtonian Dynamics (MOND).<\/p>
$\"We$
We can only see dark matter from its effect on stars and galaxies. Here, astronomers used the images of galaxies distorted by gravitational lensing to map out the dark matter, shown in blue. Credit: NASA, ESA, M. Jee and H. Ford (Johns Hopkins University)<\/figcaption><\/figure>
Euclid mission’s other science goals<\/strong><\/h2>
Studying the wealth of imaging data from both of Euclid\u2019s instruments may also reveal huge numbers of brown dwarf stars, as well as low-surface-brightness galaxies.<\/p>
Both may be much more numerous than presently known.<\/p>
Many additional discoveries are expected from the three or four \u2018Euclid Deep Fields\u2019 (adding up to more than 50 square degrees), areas that will be repeatedly imaged by Euclid at hundreds of times more sensitivity than the main survey.<\/p>
“This high-fidelity imaging of one-third of the whole sky at optical and near-infrared wavelengths is completely new territory,” says Baldry.<\/p>
“The archived data will be used by many scientists in years to come and will have a lot of legacy impact.”<\/p>
<\/div><\/figure><p class=\"p6\">No one knows for sure whether or not Euclid will really be able to figure out the true nature of dark matter and dark energy, although astronomers will certainly learn more about their spatial distribution and behaviour over time.<\/p><p class=\"p6\">“It also depends on what exactly you mean by \u2018the nature of\u2019,” says Racca.<\/p><p class=\"p6\">But even if these puzzling cosmic components remain enigmatic, Euclid\u2019s six-year mission will revolutionise our detailed knowledge of the Universe.<\/p><p class=\"p6\">As for eye-catching photographs: dark matter can\u2019t be seen and dark energy can\u2019t be imaged, but Euclid will capture absolutely stunning pictures of the Universe, with almost the same resolution as <a href=\"https:\/\/www.skyatnightmagazine.com\/space-science\/hubble-space-telescope-facts-history\/\">Hubble Space Telescope<\/a> images (one-tenth of an arcsecond), but with a much wider field of view.<\/p><p class=\"p6\">Before the end of the year, they will probably grace the pages of this very website. Stay tuned!<\/p><p><em><strong>This article originally appeared in the July 2023 issue of BBC Sky at Night Magazine.<\/strong><\/em><\/p> <\/body><\/html>\n<hr class=\"no-tts wp-block-separator\"\/>","protected":false},"excerpt":{"rendered":"<p>The new European space telescope will tackle the mysteries of dark matter and dark energy. <\/p>\n","protected":false},"author":24,"featured_media":59192,"template":"","categories":[1],"acf":{"readingTimeMinutes":"9"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies.jpg",1200,800,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies-300x200.jpg",300,200,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies-768x512.jpg",768,512,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies-1024x683.jpg",800,534,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies.jpg",1200,800,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/05\/the-euclid-mission-will-study-the-mysteries-of-the-dark-universe-by-mapping-2-billion-galaxies.jpg",1200,800,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"The new European space telescope will tackle the mysteries of dark matter and dark energy.","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/59191"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/59192"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=59191"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=59191"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}