{"id":37107,"date":"2022-10-20T00:00:00","date_gmt":"2022-10-20T00:00:00","guid":{"rendered":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/?post_type=purple_issue&p=37107"},"modified":"2023-03-30T09:03:32","modified_gmt":"2023-03-30T09:03:32","slug":"scanning-the-dark-universe-with-the-vera-rubin-observatory","status":"publish","type":"post","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/2022\/10\/20\/scanning-the-dark-universe-with-the-vera-rubin-observatory\/","title":{"rendered":"The dark Universe with the Vera Rubin Observatory"},"content":{"rendered":"\n
\"\"
High and mighty: Rubin Observatory will produce the deepest ever image of the entire southern sky <\/figcaption><\/figure>\n\n

Scanning the dark Universe with the Vera Rubin Observatory<\/h2>\n\n

Govert Schilling <\/strong>visits the revolutionary new observatory in Chile that\u2019s set to lift the lid on the mysterious, invisible dark matter that dominates the Universe <\/p>\n\n

Some 15 minutes west of the town of Vicu\u00f1a, in the Valle del Elqui in northern Chile, a steep and winding gravel road leads south from Highway 41 to the summit of Cerro Pach\u00f3n, almost 2,700 metres above sea level. Since the early 2000s, the mountaintop has been home to the 8.1-metre Gemini South Telescope and the 4.1-metre Southern Astrophysical Research Telescope. But today, the scene is dominated by a huge, futuristic cylindrical building, housing a revolutionary telescope that will uncover the Universe\u2019s darkest secrets. Welcome to the Vera C Rubin Observatory. <\/p>\n\n

The observatory\u2019s main telescope is unlike any other ever built. Its 8.4-metre diameter mirror \u2013 a novel combination of a ring-like primary mirror surrounding a much more strongly curved tertiary mirror cut from the same glass blank \u2013 has a giant 3.5\u00b0 field of view, as wide as seven full Moons strung together. Two to three times a week, a monstrous 3.2-gigapixel digital camera \u2013 the largest ever built \u2013 will snap a razor-sharp and extremely deep image every 30 seconds, covering all of the night sky visible from Chile. In 10 years\u2019 time, each and every visible star and galaxy in the southern sky will have been visited by Rubin at least 800 times: the most comprehensive survey of the cosmos ever made. \u201cRubin is absolutely unique,\u201d says Robert Blum, director for operations of the observatory. \u201cNothing like this survey has been done before.\u201d<\/span><\/p>\n\n

\"\"
The facility will house a 3.2-gigapixel camera, the largest ever built, and the world\u2019s biggest high-performance optical lens<\/figcaption><\/figure><\/div>\n\n
\"\"
The colossal 300-tonne telescope mount, onto which the giant camera and optics will be installed <\/figcaption><\/figure><\/div>\n\n

Cosmologist Catherine Heymans of the Royal Observatory Edinburgh, and the Astronomer Royal for Scotland, is equally thrilled. \u201cThis visionary project has been part of my academic life since I started my PhD in 2000,\u201d she says. \u201cI was so delighted when the UK joined Rubin in 2015 and I officially became a part of this groundbreaking new initiative. Everyone is excited about what we might find.\u201d <\/p>\n\n

Completion of the new observatory, which is a partnership of the US National Science Foundation (NSF) and the US Department of Energy (DOE), was delayed by a couple of years because of the COVID-19 pandemic, but according to Blum, first light is now expected in early 2024, with full science operations scheduled to start later that year. \u201cAll of the main telescope subsystems and mirrors are in Chile and nearly ready for integration,\u201d he says. Initial alignment of the system, including installation of a smaller commissioning camera, should have been done by the time you read this article. \u201cWe hope to ship the main camera to Chile around February 2023,\u201d says Blum. <\/p>\n\n

This giant camera, built by DOE\u2019s SLAC National Accelerator Laboratory in California and weighing more than three tonnes, is an engineering marvel in itself. Its 25-inch diameter focal plane is covered by 189 CCD detectors of 16 million pixels each. Cooled down to \u2013100\u00b0C for better sensitivity, the array registers stars as faint as 25th magnitude in exposures of a mere 30 seconds through one of six broadband filters. After each exposure, the extremely compact and stiff telescope will slew to its next position in just five seconds, night after cloudless night. Known as the Legacy Survey of Space and Time (LSST), the project will take a whopping 200,000 images per year and has an expected data rate of 10\u201320 terabytes every night.<\/span><\/p>\n\n

\"\"
Rubin\u2019s goals include unravelling how dark energy influences galaxy clusters like the Virgo Cluster<\/figcaption><\/figure><\/div>\n\n
Bigger, wider, deeper <\/strong><\/h5>\n\n

LSST is not the first deep cosmological survey. \u201cThere have been some wonderful projects before,\u201d says camera project scientist Steven Ritz from University of California at Santa Cruz, \u201cbut the combination of the Vera C Rubin Observatory\u2019s large field of view and depth really makes for something new altogether.\u201d <\/p>\n\n

Heymans notes that Rubin will cover almost 700 times the area of the Hyper Suprime-Cam (HSC) deep survey on the Japanese 8.2-metre Subaru Telescope in Hawaii (which has a more or less comparable sensitivity), while it produces significantly deeper images than the Dark Energy Survey (DES) on the nearby 4-metre Victor M Blanco Telescope at Cerro Tololo Inter-American Observatory, which covered 3.6 times less sky than Rubin will. <\/p>\n\n

Like DES and the smaller HSC survey, the Legacy Survey of Space and Time is a dark energy experiment. Dark energy is a theoretical energy that is pushing the Universe apart, which has been hypothesised to explain why cosmic expansion is accelerating. One of the goals of the Rubin Observatory is to find out how this mysterious property has evolved over cosmic time and how it has influenced the growth of large-scale structures like clusters and superclusters. This can be achieved by precisely mapping the three-dimensional distribution of billions of galaxies.<\/span><\/p>\n\n

\"\"
The camera team celebrate attaching the cryostat, with its 28-inch lens and 201 sensors, onto the camera body <\/figcaption><\/figure><\/div>\n\n

Moreover, it will be able to study minute distortions in the images of galaxies \u2013 caused by a phenomenon known as weak gravitational lensing \u2013 which can directly measure how mass is distributed in space, including the invisible dark matter that is believed to make up some 85 per cent of all the gravitating stuff in the Universe.<\/span><\/p>\n\n

Astronomers are confident that dark energy and dark matter play a pivotal role in the evolution of the Universe, but they have few clues as to the true nature of these two mysterious ingredients. \u201cWith the avalanche of data that Rubin brings, we will be confronting a wide range of both conventional and exotic theories on the dark side of our Universe,\u201d says Heymans. <\/p>\n\n

Apart from stationary stars and galaxies, Rubin will also discover millions of moving objects, like remote comets, asteroids, Kuiper Belt objects (which lie beyond Neptune\u2019s orbit), near-Earth objects that might pose an impact threat to our home planet, and maybe even the hypothetical Planet Nine in the distant reaches of the Solar System. \u201cThe wealth of new Solar System objects we will uncover is superexciting,\u201d says Blum.<\/span><\/p>\n\n

There are many other discovery opportunities, especially in time-domain astronomy: the ability to study how the whole sky changes over a wide range of timescales, which Heymans refers to as \u2018whooshflash-bang astronomy\u2019. <\/p>\n\n

\u201cThere\u2019s a lot going on that we don\u2019t yet understand,\u201d says Ritz. <\/p>\n\n

\"\"
Planet Nine \u2013 an unseen ninth world possibly hiding in our Solar System \u2013 could finally be within grasp <\/figcaption><\/figure><\/div>\n\n
Data avalanche on its way <\/strong><\/h5>\n\n

Rubin\u2019s repeated visits to the same areas of sky will yield hundreds of \u2018alerts\u2019 per second where something has changed: countless variable stars, stellar flares, novae and supernovae, but also the optical counterparts of explosive events like gamma-ray bursts, fast radio bursts, tidal disruption events and gravitational wave sources. <\/p>\n\n

\u201cI am most excited to see how our community works with the alert stream,\u201d says Blum. \u201cI am also anxious to see how successful we will be in setting up a network of telescopes for follow-up observations.\u201d <\/p>\n\n

Operated by NSF\u2019s National Optical-Infrared Astronomy Research Laboratory (NOIRLab) and SLAC, the Vera C Rubin Observatory will take 10 years to complete the LSST project. Right now, no one knows what it will bring. <\/p>\n\n

\u201cI have learned not to speculate,\u201d says Ritz. \u201cScience often has surprises, which is great. We really want to see what doesn\u2019t fit our expectations, because that\u2019s often the first step in a great discovery.\u201d <\/p>\n\n

As for the cosmological conundrums that scientists are faced with, Heymans sees two possible scenarios. The first is what many astronomers already think is the case: that dark energy doesn\u2019t change over time. \u201cI fear that would lead us no further in our journey to truly understand the origin of the dark Universe,\u201d says Blum. <\/p>\n\n

\u201cThe second scenario is that we find evidence of dark energy evolving and changing with time or space. That would allow for the existence of a new force field, which could possibly be coupled to the gravitational field. Who knows what we\u2019ll find \u2013 but with Rubin the discovery potential is endless.\u201d <\/p>\n\n

<\/div>
\n

The view from space<\/h4>\n\n\n\n

Two upcoming space telescopes will work together with Rubin to understand the unseen Universe <\/strong><\/p>\n\n\n\n

\"\"
Like Rubin, Euclid (left) and Nancy Roman (right) will scour the skies for dark energy and dark matter <\/span><\/figcaption><\/figure><\/div>\n\n\n\n

In 2023, even before the Vera C Rubin Observatory begins its unprecedentedly thorough survey of the distant Universe, the European Space Agency will launch its 1.2-metre diameter Euclid space telescope, which is pursuing very similar goals: studying dark energy and dark matter by precisely mapping and imaging billions of galaxies. Four years later, NASA will follow suit with its 2.4-metre Nancy Grace Roman Space Telescope. So how do the three projects compare? <\/p>\n\n\n\n

According to Catherine Heymans from the Royal Observatory Edinburgh, Rubin will dwarf Euclid and Roman in terms of sensitivity, because of its much larger primary mirror. But, she adds, the Rubin Observatory sits underneath the Earth\u2019s atmosphere and won\u2019t be able to obtain images as crisp as those captured by the two space telescopes. <\/p>\n\n\n\n

\u201cThe secret that is rarely openly discussed, however,\u201d she says, \u201cis that these telescopes need each other in order to truly succeed in their scientific goals. Euclid requires Rubin\u2019s multicolour imaging, and Rubin can benefit from high-resolution data [from space] to untangle the many blended galaxy images it will see.\u201d <\/p>\n\n\n\n

How exactly the data from these instruments will be combined is still a topic of hot discussion, says Heymans, but by working together they will be able to address a wide array of different science goals. <\/p>\n<\/div><\/section>\n\n

The name game <\/strong><\/h4>\n\n

The observatory is named after pioneering astronomer Vera C Rubin <\/strong><\/p>\n\n

\"\"
Rubin established some of the first evidence for dark matter\u2019s existence <\/figcaption><\/figure><\/div>\n\n

The revolutionary telescope under construction at Cerro Pach\u00f3n was originally called the Large Synoptic Survey Telescope, but in early 2020 it was announced the new observatory would be named after American astronomer Vera C Rubin (1928\u20132016). Starting in the late 1960s, Rubin, together with her Carnegie Institution of Washington colleague Kent Ford, measured the rotational properties of the Andromeda Galaxy and a number of other nearby spiral galaxies, and found convincing evidence for the existence of invisible, dark matter in the outskirts of these stellar systems. <\/p>\n\n

The concept of dark matter is much older and radio astronomers had made similar observations before, but US Congress decided on the name change to honour Rubin\u2019s pioneering work in the field of dark matter research, as well as in overcoming gender-based discrimination, paving the way for other women in astronomy. The 8.4-metre telescope of the observatory is now officially known as the Simonyi Survey Telescope, after a major private donor. Meanwhile, the original acronym LSST was saved: it now denotes the observatory\u2019s Legacy Survey of Space and Time. <\/p>\n\n

<\/div>
\n

Interview: J Anthony Tyson <\/strong><\/h4>\n\n\n\n

Tyson first proposed the observatory that would become Rubin in 1996, directed the project for 15 years and is now its chief scientist <\/p>\n\n\n\n

\"\"<\/figure><\/div>\n\n\n\n

What are the differences between your original Dark Matter Telescope proposal and the final observatory? <\/strong><\/p>\n\n\n\n

Not that much. The large aperture and the corresponding need for a gigapixel camera are set by the needed throughput to carry out one comprehensive deep-sky survey. So that hasn\u2019t changed. The main difference is the huge effort we have put into data management and software development. <\/p>\n\n\n\n

How has the 1998 discovery of dark energy impacted the science case for the project? <\/strong><\/p>\n\n\n\n

The discovery of dark energy, using a previous camera we built called the Big Throughput Camera, added an important new science motivation for what was originally called the Large Synoptic Survey Telescope [now renamed the Legacy Survey of Space and Time]. But an even more important development has been the growth of time-domain astronomy. A good example is gravitational wave bursts, which Rubin will follow up. <\/p>\n\n\n\n

Which results are you looking forward to most? <\/strong><\/p>\n\n\n\n

My main interest is in cosmology; the \u2018new\u2019 physics of dark matter and dark energy. There are multiple probes of that with the upcoming survey. But I\u2019m most excited about the discovery of the unexpected. <\/p>\n<\/div><\/section>\n\n

\"\"<\/figure><\/div>\n\n

Govert Schilling\u2019s <\/strong>book The Elephant in the Universe <\/em>is published by Harvard University Press. <\/p>\n\n

<\/p>\n\n

<\/div>\n\n

Photos: RUBIN OBSERVATORY\/NOIRLAB\/AURA\/NSF\/B. QUINT; RUBIN OBSERVATORY\/J. ANDREW, RUBIN OBSERVATORY\/NOIRLAB\/NSF\/AURA, ESA\/C. CARREAU, GSFC\/SVS, ANTONIOSOLANO\/ISTOCK\/GETTY IMAGES, JACQUELINE RAMSEYER ORRELL\/SLAC NATIONAL ACCELERATOR LABORATORY; FABIAN NEYER\/CCDGUIDECOM, GETTY, NAZARII NESHCHERENSKYI\/ISTOCK\/GETTY IMAGES<\/p>\n","protected":false},"excerpt":{"rendered":"

We visit the giant new instrument joining the hunt for dark energy<\/p>\n","protected":false},"author":24,"featured_media":37097,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"ub_ctt_via":"","purple_page_number":"34","purple_custom_meta_purple_page_number":"34","purple_seq_number":"1","purple_custom_meta_purple_seq_number":"1","purple_source_article":"article_34-1.xml","purple_custom_meta_purple_source_article":"article_34-1.xml","purple_source_issue":"November-2022","purple_custom_meta_purple_source_issue":"November-2022","purple_external_id":"November-2022-34-1","purple_custom_meta_purple_external_id":"November-2022-34-1","purple_issue_code":"|0000086558||","purple_custom_meta_purple_issue_code":"|0000086558||","purple_android_product":"com.im.skyatnight.210","purple_custom_meta_purple_android_product":"com.im.skyatnight.210","purple_ios_product":"com.im.skyatnight.210","purple_custom_meta_purple_ios_product":"com.im.skyatnight.210","purple_web_product":"","purple_custom_meta_purple_web_product":"","purple_publication_id":"075fab74-0a21-4201-866a-899d6c41c40c","purple_migrated":"","kt_blocks_editor_width":""},"categories":[21],"tags":[88,14],"featured_image_src":"https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/10\/079bcf05-2027-4ab0-9d7f-14487716c5b8.jpg","author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"acf":{"readingTimeMinutes":"11","apple_news_title":""},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/10\/079bcf05-2027-4ab0-9d7f-14487716c5b8.jpg",2048,1448,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/10\/079bcf05-2027-4ab0-9d7f-14487716c5b8-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/10\/079bcf05-2027-4ab0-9d7f-14487716c5b8-300x212.jpg",300,212,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/10\/079bcf05-2027-4ab0-9d7f-14487716c5b8-768x543.jpg",768,543,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/10\/079bcf05-2027-4ab0-9d7f-14487716c5b8-1024x724.jpg",800,566,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/10\/079bcf05-2027-4ab0-9d7f-14487716c5b8-1536x1086.jpg",1536,1086,true],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/10\/079bcf05-2027-4ab0-9d7f-14487716c5b8.jpg",2048,1448,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":"We visit the giant new instrument joining the hunt for dark energy","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/37107"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"replies":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/comments?post=37107"}],"version-history":[{"count":6,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/37107\/revisions"}],"predecessor-version":[{"id":37930,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/37107\/revisions\/37930"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/37097"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=37107"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=37107"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/tags?post=37107"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}