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article { margin-bottom: 0; } #featured-post-5 h4 { font-size: 2.6rem; font-weight: 600; padding-top: 0; } /* -- */ #media_video-3 { background-color: #f5f5f5; padding: 0px 0px 0px 0px; } @media only screen and (max-width: 800px) { .one-half { margin: 0; width: 100%; } } .home h1.entry-title { display: none; margin-bottom: 0; } .home h2.entry-title { display: none; margin-bottom: 0; } .entry-header::after { display: block; margin: 0 auto 0px; padding-bottom: 0px; width: 10%; border-bottom: none; } #text-6 .textwidget { padding-bottom: 5rem; } .home-section-2 { background-color: #f5f5f5; } #text-13 .widget-wrap a { font-weight: 600; color: #00A0B2; } #text-13 .widget-wrap { font-size: 2.6rem; text-align: left; line-height: 150%; color: #999; } /* ---- HOME Highlights ---- */ #highlights { display: flex; flex-wrap: wrap; align-content: flex-start; justify-content: center; margin-top: -80px; padding-bottom: 0%; } #highlights a { flex-grow: 1; flex-basis: 255px; max-width: 300px; margin: 10px; } #highlights img { width: 100%; } #highlights h3 { font-size: 2.6rem; font-weight: 600; } .home-even .wrap, .home-odd .wrap { max-width: 980px; padding-left: 20px; padding-right: 20px; } p.more-from-category { display: none; } .one-half { padding: 3%; background: black; /* For browsers that do not support gradients */ background: linear-gradient(to bottom, rgba(0,0,0,.1), rgba(0,0,0,.8), rgba(0,0,0,.3)); /* Standard syntax (must be last) */ } .two-sixths { padding: 3%; background: black; /* For browsers that do not support gradients */ background: linear-gradient(to bottom, rgba(0,0,0,.1), rgba(0,0,0,.8), rgba(0,0,0,.3)); /* Standard syntax (must be last) */ } .one-sixth { padding: 3%; background: black; /* For browsers that do not support gradients */ background: linear-gradient(to bottom, rgba(0,0,0,.1), rgba(0,0,0,.8), rgba(0,0,0,.3)); /* Standard syntax (must be last) */ } .home-even.home-section-4.widget-area { background-color: #f8f8f8; margin-top: 0; padding-top: 40px; } .home h2 { font-size: 3.5rem; } .home-section-1 p { font-size: 2.0rem; } .home-section-2 h3.widgettitle.widget-title { display: none; } .home-section-2 h1 { font-size: 4.0rem; } .home-section-2.widget-area { margin-bottom: -60pt; } /* ---- HOME News ---- */ .home-section-4.widget-area { background-color: #f5f5f5; margin-top: 2%; margin-bottom: -100pt; } .home-section-4 h3.widgettitle.widget-title { font-size: 4.0rem; margin-bottom: 30pt; } .home-section-4 h4 { margin-top: -30pt; margin-bottom: -30pt; font-size: 2.0rem; } /* ---- HOME Sponsors ---- */ #custom_html-6 > div { display: flex; } ul.sponsor { display: flex; flex-wrap: wrap; list-style-type: none; align-items: center; justify-content: space-around; } li.sponsor-item { flex: 0 0 35%; margin: 20px; list-style-type: none; } li.sponsor-page-item { flex: 0 0 45%; margin: 12px; list-style-type: none; } .entry-content ul > li.sponsor-item { list-style-type: none; } .entry-content ul > li.sponsor-page-item { list-style-type: none; } @media only screen and (max-width: 800px) { ul.sponsor { flex-direction: column; flex-wrap: wrap; flex: 0 1 180px; align-items: center; max-width: 350px } .post-102 .entry-content p { text-align: center; } li.sponsor-item { margin: 30px; } } #custom_html-6 h3 { color: #999; padding-bottom: 20px; } #text-9 h3 { font-size: 3.3rem; color: #999; } /* CATEGORY -- ARCHIVE */ .category h2 { font-size: 18px; } .category article { margin-bottom: auto } .category div.site-inner { margin-bottom: 10%; } .category #genesis-sidebar-primary.sidebar.sidebar-primary.widget-area { margin-top: 160px; } .category-meet-a-desi-member h2 { font-size: 26px; font-weight: 700; padding-top: 20px; border-top: 2px solid #dedede; } .entry-header, .entry-title a { color: #00a0af; text-align: left; padding-bottom: 1%; font-weight: 600; font-size: 2.6rem;} .archive #genesis-sidebar-primary { background-color: #f8f8f8; padding: 0px; margin-top: 15%; } .archive #genesis-sidebar-primary h3.widget-title { font-size: 2rem; font-weight: 500; padding-bottom: 10px; } .archive #genesis-sidebar-primary h4.entry-title { font-size: 3rem; color: #00a0af; margin-bottom: 0; } .archive .sidebar .entry-title a { font-size: 2rem; color: #00a0af; margin-bottom: 0; } /* ARCHIVE PAGES */ .archive-description, .author-box { border-bottom: none; border-top: none; } .archive-title { font-size: 4.667rem; color: #333; font-weight: 500; line-height: 1; margin-bottom: 0; text-align: left; } .archive-description, .author-box { margin-bottom: 30px; } /* SIDEBAR */ .sidebar li { font-family: open-sans, sans-serif; font-size: 100%; line-height: 1.25; margin-bottom: 5%} .sidebar a:visited { color: #999; } ul#menu-blog, ul#menu-blog-spanish, ul#menu-collaboration, ul#menu-education-outreach, ul#menu-for-scientists, ul#menu-gallery, ul#menu-instrument, ul#menu-instrument-catalan, ul#menu-instrument-italian, ul#menu-instrument-spanish, ul#menu-meet-a-member, ul#menu-meet-a-member-spanish, ul#menu-press, ul#menu-science, ul#menu-science-catalan, ul#menu-science-chinese, ul#menu-science-english, ul#menu-science-french, ul#menu-science-georgian, ul#menu-science-german, ul#menu-science-italian, ul#menu-science-korean, ul#menu-science-portuguese, ul#menu-science-spanish { background-color: #f8f8f8; padding: 8%; } #nav_menu-17 { background-color: #f8f8f8; padding: 8%; } #nav_menu-17 h3 { margin-bottom: 0; } /* PAGES */ h1.entry-title { font-size: 4.8rem; margin-bottom: 6%; text-align: left; } div.photo-summary img { margin-bottom: 4%; } /* FULL-WIDTH */ .full-width .content { padding-right: 0px; font-size: 1.8rem; font-family: open-sans, sans-serif; } .full-width h1.entry-title { padding-left: 0px; } /* MISC */ .institute { font-weight: bold; color: #099; } hr { border-bottom: 1px solid #ddd; } /* EXTERNAL LINKS */ a.ext:after, .ext a:after, h3.ext:after { content: ''; display: inline-block; /* float: right; */ margin-left: 10px; width: 12px; height: 12px; background-image: url(/wp-content/uploads/sites/8/2018/06/ext-1.png); background-size: 24px 12px; background-repeat: no-repeat; background-position: -12px 0; } a.ext.white:after, .ext.white a:after, a.ext:hover:after, .ext a:hover:after { background-position:0 0; } .home-middle .ext:after, .entry-title-link.ext:after { content: ''; display: inline-block; width: 12px; height: 12px; background-image: url(images/ext.png); background-size:24px 12px; background-repeat:no-repeat; background-position:-12px 0; margin-left:8px; float:none; } /* ---- Flex Gallery ---- */ .children { display: flex; flex-flow: row wrap; justify-content: space-around; min-height: 200px; } .child { flex: 0 0 auto; list-style-type: none; width: 30%; padding: 25px; border: solid 1px #ddd; font-size: 1.6rem; } .child a { background-color: #fff; display: block; padding: 0; background-repeat: no-repeat; background-size: contain; background-position: center top; color: #333333; text-decoration: none; text-align: center; position: relative; } .child h3 { text-decoration: none; text-align: center; font-size: 2.3rem; font-weight: 600; /* letter-spacing: 3px; */ color: #fff; line-height: 0; margin-bottom: 0; } /* ---- FOOTER ---- */ .social-links img { height: 40px; padding-right: 20px; } a.footer-button { color: white; padding: 16px; text-align: center; text-decoration: none; display: inline-block; font-size: 16px; margin: 4px 30px 30px 0px; cursor: pointer; border-radius: 8px; border: 1px solid #fff; } .site-footer { display: none; } .footer-widgets a { text-decoration: none; display: inline; } footer .footer-social { margin: 36px 0 24px 0; padding: 0; font-size: 30px; text-align: center; } .copyright { font-size: 70%; padding-top: 20px; } .wp-caption-text { margin-top: 8px; }</style></head> <body class="page-template-default page page-id-15 custom-header header-image content-sidebar genesis-breadcrumbs-hidden genesis-footer-widgets-visible" itemscope itemtype="https://schema.org/WebPage"><div class="site-container"><ul class="genesis-skip-link"><li><a href="#genesis-content" class="screen-reader-shortcut"> Skip to main content</a></li><li><a href="#genesis-sidebar-primary" class="screen-reader-shortcut"> Skip to primary sidebar</a></li><li><a href="#genesis-footer-widgets" class="screen-reader-shortcut"> Skip to footer</a></li></ul><header class="site-header" itemscope itemtype="https://schema.org/WPHeader"><div class="wrap"><div class="title-area"><p class="site-title" itemprop="headline"><a href="https://www.desi.lbl.gov/">Dark Energy Spectroscopic Instrument (DESI)</a></p></div><div class="widget-area header-widget-area"><section id="nav_menu-20" class="widget widget_nav_menu"><div class="widget-wrap"><nav class="nav-header" itemscope itemtype="https://schema.org/SiteNavigationElement"><ul id="menu-main-navigation" class="menu genesis-nav-menu js-superfish"><li id="menu-item-59" class="menu-item menu-item-type-post_type menu-item-object-page current-menu-ancestor current-menu-parent current_page_parent current_page_ancestor menu-item-has-children menu-item-59"><a href="https://www.desi.lbl.gov/science/" itemprop="url"><span itemprop="name">/ science /</span></a> <ul class="sub-menu"> <li id="menu-item-994" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-994"><a href="https://www.desi.lbl.gov/science/" itemprop="url"><span itemprop="name">science overview</span></a></li> <li id="menu-item-77" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-77"><a href="https://www.desi.lbl.gov/cosmology-and-dark-energy/" itemprop="url"><span itemprop="name">cosmology and dark energy</span></a></li> <li id="menu-item-80" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-80"><a href="https://www.desi.lbl.gov/redshifts-and-distance/" itemprop="url"><span itemprop="name">redshifts and distance</span></a></li> <li id="menu-item-79" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-79"><a href="https://www.desi.lbl.gov/mapping-the-universe/" itemprop="url"><span itemprop="name">mapping the universe</span></a></li> <li id="menu-item-81" class="menu-item menu-item-type-post_type menu-item-object-page current-menu-item page_item page-item-15 current_page_item menu-item-81"><a href="https://www.desi.lbl.gov/the-desi-science-mission/" aria-current="page" itemprop="url"><span itemprop="name">the DESI science mission</span></a></li> <li id="menu-item-82" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-82"><a href="https://www.desi.lbl.gov/the-desi-survey/" itemprop="url"><span itemprop="name">the DESI survey</span></a></li> <li id="menu-item-78" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-78"><a href="https://www.desi.lbl.gov/imaging-surveys/" itemprop="url"><span itemprop="name">imaging surveys</span></a></li> </ul> </li> <li id="menu-item-60" class="menu-item menu-item-type-post_type menu-item-object-page 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system</span></a></li> <li id="menu-item-93" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-93"><a href="https://www.desi.lbl.gov/data-systems/" itemprop="url"><span itemprop="name">data systems</span></a></li> <li id="menu-item-91" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-has-children menu-item-91"><a href="https://www.desi.lbl.gov/bringing-desi-to-life/" itemprop="url"><span itemprop="name">bringing DESI to life</span></a> <ul class="sub-menu"> <li id="menu-item-212" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-212"><a href="https://www.desi.lbl.gov/bringing-desi-to-life/commissioning-instrument/" itemprop="url"><span itemprop="name">commissioning Instrument</span></a></li> <li id="menu-item-213" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-213"><a href="https://www.desi.lbl.gov/bringing-desi-to-life/protodesi/" itemprop="url"><span itemprop="name">protoDESI</span></a></li> </ul> </li> </ul> </li> <li id="menu-item-61" class="collaboration menu-item menu-item-type-post_type menu-item-object-page menu-item-has-children menu-item-61"><a href="https://www.desi.lbl.gov/collaboration/" itemprop="url"><span itemprop="name">/ collaboration /</span></a> <ul class="sub-menu"> <li id="menu-item-169" class="ext menu-item menu-item-type-custom menu-item-object-custom menu-item-169"><a href="https://desi.lbl.gov/trac/wiki/PublicPages/Contacts" itemprop="url"><span itemprop="name">DESI team</span></a></li> <li id="menu-item-1020" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-1020"><a href="https://www.desi.lbl.gov/collaboration/desi-builders/" itemprop="url"><span itemprop="name">DESI builders</span></a></li> <li id="menu-item-113" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-113"><a href="https://www.desi.lbl.gov/collaborating-institutions/" itemprop="url"><span itemprop="name">collaborating institutions</span></a></li> <li id="menu-item-112" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-112"><a href="https://www.desi.lbl.gov/sponsors/" itemprop="url"><span itemprop="name">sponsors</span></a></li> <li id="menu-item-111" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-111"><a href="https://www.desi.lbl.gov/vendors/" itemprop="url"><span itemprop="name">vendors</span></a></li> <li id="menu-item-1766" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-1766"><a href="https://www.desi.lbl.gov/coc/" itemprop="url"><span itemprop="name">code of conduct</span></a></li> <li id="menu-item-876" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-876"><a href="https://www.desi.lbl.gov/policies/" itemprop="url"><span itemprop="name">collaboration policies</span></a></li> </ul> </li> <li id="menu-item-368" class="menu-item menu-item-type-custom 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href="https://www.desi.lbl.gov/category/blog/" itemprop="url"><span itemprop="name">blog</span></a></li> <li id="menu-item-367" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-367"><a href="https://twitter.com/desisurvey?ref_src=twsrc%5Etfw" itemprop="url"><span itemprop="name">tweets by desisurvey</span></a></li> <li id="menu-item-1159" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-1159"><a href="https://www.desi.lbl.gov/acknowledgements/" itemprop="url"><span itemprop="name">acknowledgments</span></a></li> </ul> </li> <li id="menu-item-366" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-has-children menu-item-366"><a href="/photos/" itemprop="url"><span itemprop="name">/ galleries /</span></a> <ul class="sub-menu"> <li id="menu-item-133" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-133"><a href="https://www.desi.lbl.gov/photos/" itemprop="url"><span itemprop="name">image gallery</span></a></li> <li id="menu-item-132" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-132"><a href="https://www.desi.lbl.gov/videos/" itemprop="url"><span itemprop="name">videos</span></a></li> </ul> </li> <li id="menu-item-209" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-has-children menu-item-209"><a href="/for-scientists/" itemprop="url"><span itemprop="name">/ for scientists /</span></a> <ul class="sub-menu"> <li id="menu-item-3401" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-3401"><a href="https://data.desi.lbl.gov/doc" itemprop="url"><span itemprop="name">data releases</span></a></li> <li id="menu-item-208" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-208"><a href="https://www.desi.lbl.gov/for-scientists/instrument-design/" itemprop="url"><span itemprop="name">instrument design</span></a></li> <li id="menu-item-1512" class="menu-item menu-item-type-post_type 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itemscope itemtype="https://schema.org/CreativeWork"><div class="entry-content" itemprop="text"><p><a href="https://www.desi.lbl.gov/es/the-desi-science-mission-spanish"><img decoding="async" class="alignleft" src="https://www.desi.lbl.gov/wp-content/uploads/sites/8/2019/12/spanish-1-e1576602273893.png" width="50" height="50" /></a><a href="https://www.desi.lbl.gov/fr/the-desi-science-mission-french"><img decoding="async" class="alignleft" src="https://www.desi.lbl.gov/wp-content/uploads/sites/8/2020/03/france-512-e1585601646579.png" width="50" height="50" /></a><a href="//www.desi.lbl.gov/kr/the-desi-science-mission-korean"><img loading="lazy" decoding="async" class="alignleft" src="https://www.desi.lbl.gov/wp-content/uploads/sites/8/2020/09/Korean_flag.png" alt="" width="70" height="50" /></a><a href="https://www.desi.lbl.gov/zh/the-desi-science-mission-chinese"><img loading="lazy" decoding="async" class="alignleft" 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src="https://www.desi.lbl.gov/wp-content/uploads/sites/8/2021/08/3253480-catalonia-icon-flag_106770-e1629935057530.png" width="50" height="50" /></a><a href="https://www.desi.lbl.gov/it/the-desi-science-mission-italian"><img loading="lazy" decoding="async" class="alignleft" src="https://www.desi.lbl.gov/wp-content/uploads/sites/8/2021/12/flag_italy-600x600.png" width="50" height="50" /></a></p> <p><img loading="lazy" decoding="async" class="size-large wp-image-347 alignnone" src="/wp-content/uploads/sites/8/2018/06/calibration-lamps-1024x692.jpg" alt="" width="1024" height="692" srcset="https://www.desi.lbl.gov/wp-content/uploads/sites/8/2018/06/calibration-lamps-1024x692.jpg 1024w, https://www.desi.lbl.gov/wp-content/uploads/sites/8/2018/06/calibration-lamps-600x406.jpg 600w, https://www.desi.lbl.gov/wp-content/uploads/sites/8/2018/06/calibration-lamps-768x519.jpg 768w, https://www.desi.lbl.gov/wp-content/uploads/sites/8/2018/06/calibration-lamps-300x203.jpg 300w" sizes="auto, (max-width: 1024px) 100vw, 1024px" /></p> <div class="post-content"> <div id="smallcol"> <p class="lead">The primary cosmology mission of DESI is to study the nature of dark energy: How does its energy density evolve in time, and how does it affect the clustering of matter? To do this, DESI will use its maps to measure two cosmological effects: baryon acoustic oscillations and redshift-space distortions. The same maps will also provide other opportunities to study cosmology and the physics of galaxies, quasars, and intergalactic gas.</p> <h5><span class="underlined">Baryon Acoustic Oscillations</span></h5> <p>DESI is optimized to measure a subtle imprint in the maps that is all that remains of an important physical process in the early universe known as the baryon acoustic oscillations (BAO). To explain this effect, we must first account for the cosmic microwave background radiation鈥攖he heat left over from the Big Bang鈥攖hat fills the universe. Today the temperature is only 2.7 <img loading="lazy" decoding="async" class="alignleft wp-image-348" src="/wp-content/uploads/sites/8/2018/06/desi2-e1512065402877-1024x783.png" alt="" width="420" height="321" srcset="https://www.desi.lbl.gov/wp-content/uploads/sites/8/2018/06/desi2-e1512065402877-1024x783.png 1024w, https://www.desi.lbl.gov/wp-content/uploads/sites/8/2018/06/desi2-e1512065402877-600x459.png 600w, https://www.desi.lbl.gov/wp-content/uploads/sites/8/2018/06/desi2-e1512065402877-768x587.png 768w, https://www.desi.lbl.gov/wp-content/uploads/sites/8/2018/06/desi2-e1512065402877-300x229.png 300w, https://www.desi.lbl.gov/wp-content/uploads/sites/8/2018/06/desi2-e1512065402877.png 1125w" sizes="auto, (max-width: 420px) 100vw, 420px" />degrees above absolute zero, but at earlier times it was much hotter. Prior to 400,000 years after the Big Bang, when the universe was over a billion times denser than it is today, the background radiation was hot enough to cause the hydrogen and helium to be ionized, separating the electrons from atomic nuclei and forming a plasma. The electrons scattered easily with the photons of the background and the photons provided a very strong radiation pressure that resisted compression of the gas. Density perturbations created in the first fraction of a second of the universe thereby traveled as sound waves, or baryon acoustic oscillations, in this plasma. The sound waves traveled through the universe for 400,000 years, coming to a halt when the expanding universe cooled enough that the electrons and nuclei combined into neutral atoms. At this point, the gravitational forces of the density perturbations dominated and started to shape the universe into the large-scale structure that we see today. But the effect of the sound waves can still be measured: Around each overdense region there is a faint spherical imprint of the wave that left that region. This has created a slight tendency for pairs of galaxies to be separated by the distance the waves traveled, which owing to the expanding Universe is about 500 million light-years today. This faint relic imprint has been observed in several data sets, most notably from the Sloan Digital Sky Survey (<strong>SDSS</strong>) and its Baryon Oscillation Spectroscopic Survey (<strong>BOSS</strong>).This subtle correlation is now a major player in the study of dark energy.</p> <p>When we observe a sample of galaxies at high redshift and detect their distinctive clustering scale, we know that the scale is 500 million light-years. With that, we can infer the distance to the galaxies. It is as if the redshift survey has given us a map without an obvious conversion of inches to miles鈥攂y careful analysis on the spacing of the galaxies we can infer the correct scaling factor. DESI will use the BAO to measure the relationship of distance to redshift over a wide range of redshifts with subpercent precision. This in turn allows us to infer the expansion history and the evolution of dark energy.</p> <h5><span class="underlined">Redshift-space distortions</span></h5> <p>When DESI measures the redshift of galaxies, this measurement is actually composed of two contributions: the large shift coming from the cosmological expansion of the universe, and a smaller shift that results from the motion of the galaxy due to the gravitational pull from the universe’s surrounding large-scale structure. The latter is known as the peculiar velocity. By measuring the size of the peculiar velocity, scientists can measure the amount of mass in the large-scale structure.</p> <p>Or if that is known from other methods, we can test whether gravitational attractions on scales of hundreds of millions of light-years follows the predictions of Albert Einstein’s theory of general relativity, which relates to gravity. The testing of general relativity on these enormous scales is important as it might reveal alternative explanations, known as modified gravity theories, for the universe’s accelerating expansion rate. On the very largest scales we find that the expansion rate is evolving very differently from what would be predicted from the attractions of known matter and the physics that are so well-tested on solar system scales. Perhaps this breakdown has other signatures in the universe’s large-scale structure.</p> <p>The size of the velocities can be measured in the DESI maps by comparing the characteristic amplitudes of the large-scale clustering of galaxies in directions perpendicular to the line of sight to the clustering signals in directions along the line of sight. This is known as redshift-space distortions. Because the large-scale structure we are measuring is giving rise to the peculiar velocities, there is a systematic change in the appearance of the large-scale structure. Careful analysis of the DESI maps can reveal this signature to high precision.</p> <h5><span class="underlined">DESI in the Dark Energy Portfolio</span></h5> <p>The enigma of dark energy and the ongoing appeal of cosmology continues to motivate a wide range of cosmological experiments. DESI is one of the most ambitious surveys now under development, and once operational it will quickly become the world鈥檚 largest galaxy redshift survey. The exquisite 3D maps from DESI will have great opportunity on their own, but they become even more effective when combined with data from upcoming imaging surveys in optical/infrared, microwave, and X-ray light. One of the hallmarks of modern cosmology is the ability to measure cosmological properties in multiple manners, as the comparison of results can reinforce confidence in the answers and can point the way to new opportunities. We look forward to the prominent and collaborative role that DESI will play in the cosmological portfolio of the next decade, particularly in the study of dark energy.</p> <h5><span class="underlined">Beyond Dark Energy</span></h5> <p>The DESI maps will be used for many other applications beyond baryon acoustic oscillations and redshift-space distortions. We expect that our measurements of the intermediate-redshift amplitude of large-scale structure will be important to measurements of the mass of the neutrino. Our measurements on the largest scales can test whether the initial perturbations in the universe follow the simplest model, or alternatively show correlations indicative of novel behaviors at the enormous energy scales of the first second of the universe. Detailed measurements of galaxy clustering can use gravitational clustering to test a wide range of extensions to the standard cosmological model. Beyond cosmology, DESI will measure precise distances to millions of galaxies and quasars whose properties and demographics can then be better interpreted. DESI will produce the most detailed map yet of the nearby universe, which will provide the backbone for studies of galaxy groups and clusters as well as of extreme phenomena within those galaxies. And DESI’s stellar spectroscopy will measure the dynamical state of the Milky Way halo and thick disk in great detail.</p> </div> </div> <p style="text-align: right"><strong><a href="/the-desi-survey/">the DESI survey 禄</a></strong></p> </div></article></main><aside class="sidebar sidebar-primary widget-area" role="complementary" aria-label="Primary Sidebar" itemscope itemtype="https://schema.org/WPSideBar" id="genesis-sidebar-primary"><h2 class="genesis-sidebar-title screen-reader-text">Primary Sidebar</h2><section id="nav_menu-49" class="widget widget_nav_menu"><div class="widget-wrap"><div class="menu-science-english-container"><ul id="menu-science-english" class="menu"><li id="menu-item-406" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-406"><a href="https://www.desi.lbl.gov/science/" itemprop="url">science overview</a></li> <li id="menu-item-228" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-228"><a href="https://www.desi.lbl.gov/cosmology-and-dark-energy/" itemprop="url">cosmology and dark energy</a></li> <li id="menu-item-230" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-230"><a href="https://www.desi.lbl.gov/redshifts-and-distance/" itemprop="url">redshifts and distance</a></li> <li id="menu-item-229" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-229"><a href="https://www.desi.lbl.gov/mapping-the-universe/" itemprop="url">mapping the universe</a></li> <li id="menu-item-231" class="menu-item menu-item-type-post_type menu-item-object-page current-menu-item page_item page-item-15 current_page_item menu-item-231"><a href="https://www.desi.lbl.gov/the-desi-science-mission/" aria-current="page" itemprop="url">the DESI science mission</a></li> <li id="menu-item-232" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-232"><a href="https://www.desi.lbl.gov/the-desi-survey/" itemprop="url">the DESI survey</a></li> <li id="menu-item-233" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-233"><a href="https://www.desi.lbl.gov/imaging-surveys/" itemprop="url">imaging surveys</a></li> </ul></div></div></section> </aside></div></div><div class="footer-widgets" id="genesis-footer-widgets"><h2 class="genesis-sidebar-title screen-reader-text">Footer</h2><div class="wrap"><div class="widget-area footer-widgets-1 footer-widget-area"><section id="custom_html-4" class="widget_text widget widget_custom_html"><div class="widget_text widget-wrap"><div class="textwidget custom-html-widget"><div> <p> <a href="https://desi.lbl.gov/trac/login" class="footer-button">TEAM LOGIN</a></p> <p class="social-links"> <a class="twitter" href="https://twitter.com/desisurvey" target="_blank"><img src="/wp-content/uploads/sites/8/2018/06/twitter-icon@05x.png" alt="twitter"></a>   <a class="item2 ir" href="https://www.instagram.com/desisurvey/?hl=en" target="_blank"><img src="/wp-content/uploads/sites/8/2018/06/instagram-icon@05x.png" alt="instagram"></a>   <a class="item3 ir" href="https://www.facebook.com/DESI-Survey-2104105159914082/?modal=admin_todo_tour" target="_blank"><img src="/wp-content/uploads/sites/8/2018/06/facebook-icon@05x.png" alt="facebook"></a> </p> </div> <p class="copyright"> Copyright 漏 2018 Dark Energy Spectroscopic Instrument [DESI] </p></div></div></section> </div></div></div><footer class="site-footer" itemscope itemtype="https://schema.org/WPFooter"><div class="wrap"><p>Copyright © 2025 路 <a href="http://my.studiopress.com/themes/parallax/">Parallax Pro DESI</a> on <a href="https://www.studiopress.com/">Genesis Framework</a> 路 <a href="https://wordpress.org/">WordPress</a> 路 <a href="https://www.desi.lbl.gov/wp-login.php">Log in</a></p></div></footer></div><script type="text/javascript" src="https://www.desi.lbl.gov/wp-includes/js/hoverIntent.min.js?ver=1.10.2" id="hoverIntent-js"></script> <script type="text/javascript" src="https://www.desi.lbl.gov/wp-content/themes/genesis/lib/js/menu/superfish.min.js?ver=1.7.10" id="superfish-js"></script> <script type="text/javascript" src="https://www.desi.lbl.gov/wp-content/themes/genesis/lib/js/menu/superfish.args.min.js?ver=3.4.0" id="superfish-args-js"></script> <script type="text/javascript" src="https://www.desi.lbl.gov/wp-content/themes/genesis/lib/js/skip-links.min.js?ver=3.4.0" id="skip-links-js"></script> <script type="text/javascript" id="parallax-responsive-menu-js-extra"> /* <![CDATA[ */ var genesis_responsive_menu = {"mainMenu":"Menu","subMenu":"Submenu","menuClasses":{"combine":[".nav-header",".nav-primary"]}}; 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