{"id":5122,"date":"2022-11-22T10:00:00","date_gmt":"2022-11-22T10:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=5122"},"modified":"2022-11-12T16:40:24","modified_gmt":"2022-11-12T16:40:24","slug":"one-of-the-greatest-damn-mysteries-of-physics-we-studied-distant-suns-in-the-most-precise-astronomical-test-of-electromagnetism-yet","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/one-of-the-greatest-damn-mysteries-of-physics-we-studied-distant-suns-in-the-most-precise-astronomical-test-of-electromagnetism-yet\/","title":{"rendered":"\u2018One of the greatest damn mysteries of physics\u2019: we studied distant suns in the most precise astronomical test of electromagnetism yet"},"content":{"rendered":"\n
\n \n
\n \n NASA<\/span><\/span>\n <\/figcaption>\n <\/figure>\n\nMichael Murphy<\/a>, Swinburne University of Technology<\/a><\/em><\/span>\n\n

There\u2019s an awkward, irksome problem with our understanding of nature\u2019s laws which physicists have been trying to explain for decades. It\u2019s about electromagnetism, the law of how atoms and light interact, which explains everything from why you don\u2019t fall through the floor to why the sky is blue. <\/p>\n\n

Our theory of electromagnetism is arguably the best physical theory humans have ever made \u2013 but it has no answer for why electromagnetism is as strong as it is. Only experiments can tell you electromagnetism\u2019s strength, which is measured by a number called \u03b1 (aka alpha, or the fine-structure constant<\/a>).<\/p>\n\n

The American physicist Richard Feynman, who helped come up with the theory, called this<\/a> \u201cone of the greatest damn mysteries of physics\u201d and urged physicists to \u201cput this number up on their wall and worry about it\u201d.<\/p>\n\n

In research just published in Science<\/a>, we decided to test whether \u03b1 is the same in different places within our galaxy by studying stars that are almost identical twins of our Sun. If \u03b1 is different in different places, it might help us find the ultimate theory, not just of electromagnetism, but of all nature\u2019s laws together \u2013 the \u201ctheory of everything\u201d.<\/p>\n\n

We want to break our favourite theory<\/h2>\n\n

Physicists really want one thing: a situation where our current understanding of physics breaks down. New physics. A signal that cannot be explained by current theories. A sign-post for the theory of everything.<\/p>\n\n

To find it, they might wait deep underground in a gold mine<\/a> for particles of dark matter to collide with a special crystal. Or they might carefully tend the world\u2019s best atomic clocks<\/a> for years to see if they tell slightly different time. Or smash protons together at (nearly) the speed of light in the 27-km ring of the Large Hadron Collider<\/a>.<\/p>\n\n

The trouble is, it\u2019s hard to know where to look. Our current theories can\u2019t guide us. <\/p>\n\n

Of course, we look in laboratories on Earth, where it\u2019s easiest to search thoroughly and most precisely. But that\u2019s a bit like the drunk only searching for his lost keys under a lamp-post<\/a> when, actually, he might have lost them on the other side of the road, somewhere in a dark corner.<\/p>\n\n

\n \"A<\/a>\n
\n The Sun\u2019s rainbow: sunlight is here spread into separate rows, each covering just a small range of colours, to reveal the many dark absorption lines from atoms in the Sun\u2019s atmosphere.<\/span>\n N.A. Sharp \/ KPNO \/ NOIRLab \/ NSO \/ NSF \/ AURA<\/a>, CC BY<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

Stars are terrible, but sometimes terribly similar<\/h2>\n\n

We decided to look beyond Earth, beyond our Solar System, to see if stars which are nearly identical twins of our Sun produce the same rainbow of colours. Atoms in the atmospheres of stars absorb some of the light struggling outwards from the nuclear furnaces in their cores. <\/p>\n\n

Only certain colours are absorbed, leaving dark lines in the rainbow. Those absorbed colours are determined by \u03b1 \u2013 so measuring the dark lines very carefully also lets us measure \u03b1.<\/p>\n\n

\n \"A<\/a>\n
\n Hotter and cooler gas bubbling through the turbulent atmospheres of stars make it hard to compare absorption lines in stars with those seen in laboratory experiments.<\/span>\n NSO \/ AURA \/ NSF<\/a>, CC BY<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

The problem is, the atmospheres of stars are moving \u2013 boiling, spinning, looping, burping \u2013 and this shifts the lines. The shifts spoil any comparison with the same lines in laboratories on Earth, and hence any chance of measuring \u03b1. Stars, it seems, are terrible places to test electromagnetism.<\/p>\n\n

But we wondered: if you find stars that are very similar \u2013 twins of each other \u2013 maybe their dark, absorbed colours are similar as well. So instead of comparing stars to laboratories on Earth, we compared twins of our Sun to each other.<\/p>\n\n

A new test with solar twins<\/h2>\n\n

Our team of student, postdoctoral and senior researchers, at Swinburne University of Technology and the University of New South Wales, measured the spacing between pairs of absorption lines in our Sun and 16 \u201csolar twins\u201d \u2013 stars almost indistinguishable from our Sun.<\/p>\n\n

The rainbows from these stars were observed on the 3.6-metre European Southern Observatory (ESO) telescope<\/a> in Chile. While not the largest telescope in the world, the light it collects is fed into probably the best-controlled, best-understood spectrograph: HARPS<\/a>. This separates the light into its colours, revealing the detailed pattern of dark lines. <\/p>\n\n\n\n

HARPS spends much of its time observing Sun-like stars to search for planets. Handily, this provided a treasure trove of exactly the data we needed.<\/p>\n\n

\n \"A<\/a>\n
\n The ESO 3.6-metre telescope in Chile spends much of its time observing Sun-like stars to search for planets using its extremely precise spectrograph, HARPS.<\/span>\n Iztok Bon\u010dina \/ ESO<\/a>, CC BY<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

From these exquisite spectra, we have shown that \u03b1 was the same in the 17 solar twins to an astonishing precision: just 50 parts per billion. That\u2019s like comparing your height to the circumference of Earth. It\u2019s the most precise astronomical test of \u03b1 ever performed.<\/p>\n\n

Unfortunately, our new measurements didn\u2019t break our favourite theory. But the stars we\u2019ve studied are all relatively nearby, only up to 160 light years away. <\/p>\n\n

What\u2019s next?<\/h2>\n\n

We\u2019ve recently identified new solar twins much further away, about half way to the centre of our Milky Way galaxy.<\/p>\n\n

In this region, there should be a much higher concentration of dark matter \u2013 an elusive substance astronomers believe lurks throughout the galaxy and beyond. Like \u03b1, we know precious little about dark matter, and some theoretical physicists<\/a> suggest the inner parts of our galaxy might be just the dark corner we should search for connections between these two \u201cdamn mysteries of physics\u201d.<\/p>\n\n

If we can observe these much more distant suns with the largest optical telescopes, maybe we\u2019ll find the keys to the universe.\"The<\/p>\n\n\n\n

Michael Murphy<\/a>, Professor of Astrophysics, Swinburne University of Technology<\/a><\/em><\/span><\/p>\n\n

This article is republished from The Conversation<\/a> under a Creative Commons license. Read the original article<\/a>.<\/p>\n\n","protected":false},"excerpt":{"rendered":"NASA Michael Murphy, Swinburne University of Technology There\u2019s an awkward, irksome problem with our understanding of nature\u2019s laws…\n","protected":false},"author":272,"featured_media":5094,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"nf_dc_page":"","fifu_image_url":"","fifu_image_alt":"","footnotes":""},"categories":[17,14],"tags":[642,204,75,474],"class_list":{"0":"post-5122","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-math-and-the-sciences","8":"category-space","9":"tag-electromagnetism","10":"tag-physics","11":"tag-star","12":"tag-the-conversation","13":"cs-entry","14":"cs-video-wrap"},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts\/5122","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/users\/272"}],"replies":[{"embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/comments?post=5122"}],"version-history":[{"count":1,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts\/5122\/revisions"}],"predecessor-version":[{"id":5123,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts\/5122\/revisions\/5123"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/media\/5094"}],"wp:attachment":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/media?parent=5122"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/categories?post=5122"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/tags?post=5122"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}