{"id":436637,"date":"2026-08-18T21:42:08","date_gmt":"2026-08-18T21:42:08","guid":{"rendered":"https:\/\/www.newsbeep.com\/us-ca\/436637\/"},"modified":"2026-08-18T21:42:08","modified_gmt":"2026-08-18T21:42:08","slug":"expanding-whats-known-about-our-fast-expanding-universe","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us-ca\/436637\/","title":{"rendered":"Expanding what’s known about our fast-expanding universe"},"content":{"rendered":"

The universe is full of surprises, and Saul Perlmutter knows that better than most.<\/p>\n

A professor of physics at UC Berkeley and a senior scientist at Lawrence Berkeley National Laboratory, Perlmutter had spent years studying the universe at a time when leading theories suggested its expansion was slowing down. But in 1998, he and his team made a startling discovery: The opposite was true, and the expansion was accelerating. That breakthrough led to the realization that the universe is composed of an enigmatic \u201cdark energy.\u201d It also earned him a Nobel Prize in Physics.\u00a0<\/p>\n

Perlmutter is the latest faculty member featured in After Office Hours<\/a>, a UC Berkeley News series where researchers explain, in their own words, the \u201caha\u201d moments motivating their work. Perlmutter described the joy of scientific surprises, the importance of rigorous research and why Berkeley remains at the forefront of cosmic discovery.\u00a0<\/p>\n

What was your Fiat Lux moment \u2014 the breakthrough or new insight that changed your work?<\/p>\n

Our Fiat Lux moment began when my research team graphed the data we had collected from our measurements of vastly distant exploding stars called supernovae and saw something very surprising: The graph indicated that the universe was not slowing down in its expansion as we had expected but instead was speeding up.\u00a0<\/p>\n

Scientists love surprises like this \u2014 they are once-in-a-lifetime opportunities to learn something really big about how reality works. After many months of testing and confirming the result in multiple ways, we even started to believe it was likely to be correct. Really, the breakthrough moment took months!\u00a0<\/p>\n

Now the challenge for physicists and cosmologists is to figure out what this \u201cdark energy\u201d that accelerates the expansion is.<\/p>\n

\"SaulPerlmutter\u2019s interest in teaching scientific-style critical thinking led to a Berkeley course called Sense and Sensibility and Science.<\/p>\n

Brandon S\u00e1nchez Mejia\/UC Berekely<\/p>\n

What did you get wrong early on \u2014 and what did that teach you?<\/p>\n

I remember when I realized that some early results from my team were affected by what we expected the result to be, apparently because we had hunted down computer bugs or analysis errors until we arrived at a result that we expected \u2014 and then stopped without looking for more. And just previously I had been feeling rather smug for having seen evidence of such a problem in a rival team\u2019s analysis!\u00a0<\/p>\n

From then on, we learned to always hide the results from ourselves while debugging any analysis. That \u201cblind analysis\u201d has become a standard in the field \u2014 and makes us more open to the possibility of reality surprising us again!<\/p>\n

What\u2019s a question in your field that nobody has a good answer to yet?<\/p>\n

One of the real excitements of this work is the fact that it\u2019s revealed a key puzzle about reality: Apparently most of the universe is made up of this so-called dark energy and we still don\u2019t know what it is! Sizable parts of physics, astrophysics and cosmology are now devoted to pursuing this question \u2014 with an impressive collection of those world-leading efforts happening right here in Berkeley.<\/p>\n","protected":false},"excerpt":{"rendered":"The universe is full of surprises, and Saul Perlmutter knows that better than most. A professor of physics…\n","protected":false},"author":2,"featured_media":436638,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[34],"tags":[124623,143,145,144],"class_list":["post-436637","post","type-post","status-publish","format-standard","has-post-thumbnail","category-oakland","tag-after-office-hours","tag-oakland","tag-oakland-headlines","tag-oakland-news"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts\/436637","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/comments?post=436637"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts\/436637\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/media\/436638"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/media?parent=436637"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/categories?post=436637"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/tags?post=436637"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}