{"id":6037,"date":"2017-08-11T10:05:21","date_gmt":"2017-08-11T09:05:21","guid":{"rendered":"https:\/\/ounews.co\/?p=6037"},"modified":"2017-08-11T10:05:21","modified_gmt":"2017-08-11T09:05:21","slug":"suns-core-rotates-four-times-faster-surface-heres-matters","status":"publish","type":"post","link":"https:\/\/www.open.ac.uk\/blogs\/news\/science-mct\/space\/suns-core-rotates-four-times-faster-surface-heres-matters\/","title":{"rendered":"The sun’s core rotates four times faster than its surface \u2013 here’s why it matters"},"content":{"rendered":"

My favourite science news is the stuff that changes the way I think about the world and our place in the universe. Many dinosaurs were covered in feathers; there\u2019s a planet in the habitable zone around the nearest star in the night sky; the universe is expanding faster and faster but no one yet knows why.<\/p>\n

Now there\u2019s a genuinely awe-inspiring and amazing discovery that really has changed the way I think about our solar system. A team of astronomers have discovered<\/a> that the core of our sun rotates about four times faster than the surface. It\u2019s in the middle of our solar system, on our cosmic doorstep, so how could we have missed that before? And why is it important?<\/div>\n

It\u2019s not easy to work out what\u2019s inside the sun \u2013 you can\u2019t send a probe inside to fly about. The trick is to use seismology<\/a> in a similar way that earthquakes are monitored. It\u2019s possible to work out what\u2019s inside the Earth under our feet, right to the core, without digging, by measuring how \u201cseismic waves\u201d (vibrations from earthquakes) pass through the Earth. We know from this that most of it is not liquid, contrary to popular belief, because of the so-called \u201cS-waves\u201d.<\/p>\n

These waves wiggle side to side, perpendicular to the direction of travel. They can only exist in a solid, and they pass through most of the Earth. Pressure waves or \u201cP-waves\u201d, where the wiggle is parallel to the direction of travel (like sound), can also go through liquids. From the S-waves and P-waves, we know the Earth has a solid core, a liquid outer core, and a solid mantle and crust.<\/p>\n

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Artist\u2019s impression of SOHO. NASA<\/p><\/div><\/figure>\n

To work out what\u2019s inside the sun, the ESA\/NASA Solar and Heliospheric Observatory<\/a> (SOHO for short) team has also used seismology to look at waves in the sun. In this context, it\u2019s called helioseismology. However, you can\u2019t stick an earthquake-monitor on the sun\u2019s surface, so scientists use the \u201cDoppler effect\u201d to measure waves at the sun\u2019s surface. The Doppler effect is the stretching or squashing of waves because of motion, whether it\u2019s motion of the thing emitting the wave or motion of the thing receiving the wave.<\/p>\n

In this case, sound waves wash through the sun and reach the surface, and so the sun\u2019s surface moves towards or away from SOHO. The sun\u2019s surface also gives off light, and the motion means the light waves are squashed or stretched. This change in wavelength is what the SOHO spacecraft measures, and the team translates this into information about the sound waves that reached the surface.<\/p>\n

The SOHO team spent 16 years monitoring the sound waves passing through the sun. Their careful and delicate analysis of the data managed to tease out something else going on: buoyant blobs of gas bobbing around deep inside the sun, in a phenomenon called \u201cG-waves\u201d where G is short for gravity. (These are completely different to the \u201cgravitational waves\u201d<\/a> from deep space discovered by LIGO, though.)<\/p>\n

The sound waves that pass through the sun are subtly changed in pitch by this bobbing around deep inside. The evidence from this data looks very clear: the core of the sun is rotating about once a week, instead of about once a month at the surface.<\/p>\n

This was a surprising, unexpected discovery. It\u2019s not yet understood why the sun\u2019s core has this faster spin. Perhaps it\u2019s something that was imprinted into the structure of the sun early in its life, caused by the action of magnetic fields inside the sun moving charged gas along magnetic field lines and redistributing it. This would make the sun\u2019s core a cryptic relic of the ancient history of our solar system, at a time when our planet Earth was still being formed. Understanding this is the next challenge, but either way, there is now a wonderful new way to work out what is happening deep inside the sun.<\/p>\n

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The sun\u2019s hidden interior. ESA, CC BY-SA<\/p><\/div><\/figure>\n

There\u2019s lots of very good practical reasons for funding space science: it pump-primes very high-tech industry, and every \u20ac1 invested in space returns an average \u20ac6 to the wider economy. But for me the best rationale isn\u2019t economic, it\u2019s cultural. We seek out this knowledge because it\u2019s intrinsically important, and because it\u2019s beautiful, and because these achievements are what a civilisation is remembered for in the end.<\/p>\n

\"TheI am confident that we will be remembered as the culture that discovered many dinosaurs were covered in feathers, and that there\u2019s a planet in the habitable zone around the nearest star in the night sky, and that the universe is expanding faster and faster (but no one yet knows why) \u2013 and that hidden deep inside our sun, the core is spinning four times faster than its surface.<\/p>\n

Written by Stephen Serjeant<\/a>, Professor of Astronomy, The Open University<\/a><\/em><\/p>\n

This article was originally published on The Conversation<\/a>. Read the original article<\/a>.<\/p>\n

Photo by NASA Goddard Photo and Video<\/a> <\/a><\/small><\/p>\n","protected":false},"excerpt":{"rendered":"

My favourite science news is the stuff that changes the way I think about the world and our place in the universe. Many dinosaurs were covered in feathers; there\u2019s a planet in the habitable zone around the nearest star in the night sky; the universe is expanding faster and faster but no one yet knows […]<\/p>\n","protected":false},"author":19,"featured_media":6041,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[721,2084,2155],"class_list":["post-6037","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-space","tag-dr-stephen-serjeant","tag-space-science","tag-sun"],"_links":{"self":[{"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/posts\/6037","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/users\/19"}],"replies":[{"embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/comments?post=6037"}],"version-history":[{"count":0,"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/posts\/6037\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/media\/6041"}],"wp:attachment":[{"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/media?parent=6037"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/categories?post=6037"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/tags?post=6037"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}