{"id":2423,"date":"2026-06-22T21:05:33","date_gmt":"2026-06-22T21:05:33","guid":{"rendered":"https:\/\/blog.aurorasaurus.org\/?p=2423"},"modified":"2026-06-23T18:28:41","modified_gmt":"2026-06-23T18:28:41","slug":"staying-cool-with-aurora-science","status":"publish","type":"post","link":"https:\/\/blog.aurorasaurus.org\/?p=2423","title":{"rendered":"Staying cool with aurora science"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">by Tanya Melnik and Laura Edson&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The aurora follows a \u201clife cycle\u201d called a <a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/blog.aurorasaurus.org\/?p=2158\">substorm<\/a>. We know the feeling of waiting for the most dynamic part of the substorm to light the sky with green and red ribbons, but sometimes it seems to take <em>forever<\/em>. In this post we\u2019ll go over a couple of reasons why the aurora may not be actively dancing. Since we\u2019re writing from a particularly toasty Northern Hemisphere summer, we\u2019ll use a metaphor that can double as a demo and help with staying cool! As with all metaphors, it\u2019s a simplified way of understanding a complex concept. While it\u2019s not perfectly accurate, it\u2019s useful.&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">The aurora acts like an enormous splash bucket<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Water parks sometimes feature a large bucket that fills with water and then tips over, dousing delighted visitors.&nbsp;<\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-9-16 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<div class=\"nv-iframe-embed\"><iframe loading=\"lazy\" title=\"Water bucket falling at the Splash Park \ud83d\udca6 \ud83d\udca6 \ud83d\udca7 \ud83d\udca7 \ud83d\ude32\ud83d\ude32\ud83d\ude32\" width=\"563\" height=\"1000\" src=\"https:\/\/www.youtube.com\/embed\/bL9CJ8OHYOQ?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/div>\n<\/div><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">A tipping bucket like this is a common metaphor for thinking about how an auroral substorm slowly builds energy and then bursts into a short, dynamic auroral display:<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-6.png\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"662\" src=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-6-1024x662.png\" alt=\"Three diagrams show a substorm as like a tipping bucket, a pitcher with a spout, and a combination of the two. \" class=\"wp-image-2431\" srcset=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-6-1024x662.png 1024w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-6-300x194.png 300w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-6-768x496.png 768w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-6-1536x993.png 1536w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-6.png 1772w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><figcaption class=\"wp-element-caption\">As described by Dr. Syun-Ichi Akasofu&nbsp; in his 2019 article, \u201cThe Explosive Characteristics of the Aurora: The Electric Current Line Approach\u201d (10.3389\/fspas.2019.00001), scientists have considered different versions of this metaphor, for instance: (A) a tippy pitcher model of substorms, (B) a bucket model of substorms, (C) after much discussions among researchers, it was agreed that the magnetosphere has both components.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">There are four main <a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/blog.aurorasaurus.org\/?p=2158\">phases to a substorm<\/a>, and the total time between substorms is usually about three hours.&nbsp;<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>The <strong>growth phase<\/strong>, which can last a few hours<\/li>\n\n\n\n<li>The <strong>onset or breakup phase<\/strong>, which lasts about 10-15 minutes<\/li>\n\n\n\n<li>The <strong>expansion phase<\/strong>, which lasts 15-30 minutes.<\/li>\n\n\n\n<li>The <strong>recovery phase<\/strong>, which can last an hour or more<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">During the growth phase, the Earth\u2019s magnetic system fills up with energy that it spends during the breakup and expansion phases. In other words, in the growth phase the bucket is filling; in the breakup phase it tips; in the expansion phase it spills; and in the recovery phase it rights itself, ready to fill again. During the breakup and expansion phases, the aurora can be seen further toward the equator, which is especially helpful for aurora chasers at lower latitudes. The processes that trigger breakup and expansion are hotly debated but still not fully understood.&nbsp;<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-3.png\"><img loading=\"lazy\" decoding=\"async\" width=\"819\" height=\"1024\" src=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-3-819x1024.png\" alt=\"A diagram compares the phases of a substorm with the stages of a bucket tipping and photographs of aurora. \" class=\"wp-image-2428\" style=\"aspect-ratio:0.7998289339257288;width:410px;height:auto\" srcset=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-3-819x1024.png 819w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-3-240x300.png 240w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-3-768x960.png 768w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-3.png 1080w\" sizes=\"auto, (max-width: 819px) 100vw, 819px\" \/><\/a><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">The <strong>growth phase<\/strong> looks like quiet, ribbonlike discrete auroral arcs without much motion within the structures, that gradually move toward the equator. In the <strong>breakup phase<\/strong>, the quiet arcs get more active and start to cover more of the sky, and sometimes there are auroral beads: a row of brighter spots or stripes in line along an auroral arc that last seconds to minutes. The <strong>expansion phase<\/strong> can include spectacular ribbonlike shapes, bright colors, and active movements. STEVE typically occurs at the end of the expansion phase, about one hour after the breakup phase. During the <strong>recovery phase<\/strong>, the aurora becomes diffuse and cloudlike, usually dim with much slower motion, but there can be <a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/blog.aurorasaurus.org\/?p=1792\">pulsating patches<\/a>. Sometimes the recovery phase marks the finale of a night of an aurora, but sometimes another substorm happens right afterward, especially on active nights.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This pattern usually happens in a fairly regular way, but on occasion we find ourselves stuck in the growth phase, waiting impatiently. What\u2019s going on?<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Sometimes the bucket takes a long time to fill<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">When the solar wind first arrives, we feel eager to see that beautiful expansion phase. But filling a giant space bucket from empty takes a long time, and how long it takes has to do with how quickly the metaphorical water is pouring in. There are conditions that can slow the flow.&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For example, <a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/blog.aurorasaurus.org\/?p=1257\">Bz<\/a> is the direction of the incoming space weather\u2019s magnetic field. If it is the same as Earth\u2019s magnetic field (which is in the Bz north direction), it deflects and not as much energy flows into the system that drives aurora. If it is the opposite of Earth\u2019s magnetic field (Bz south), it <a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/www.youtube.com\/watch?v=OSWLRLaTXpk\">reconnects<\/a> with Earth\u2019s magnetic field and pours lots of energy into the system.&nbsp;<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-4.png\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-4-1024x683.png\" alt=\"A diagram compares Bz flow with a faucet or spigot valve.\" class=\"wp-image-2429\" style=\"aspect-ratio:1.4993135011441647;width:412px;height:auto\" srcset=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-4-1024x683.png 1024w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-4-300x200.png 300w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-4-768x512.png 768w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-4-930x620.png 930w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-4.png 1182w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">It\u2019s a little like a spigot valve that can close or open, changing how much water flows into the bucket. If Bz is fluctuating a lot, it\u2019s like someone turning the spigot valve off and on over and over, and the bucket will fill more slowly. If Bz has been north for a while and then suddenly turns south, more water begins to flow into the bucket, but it will still take time to fill all the way. The growth phase can take several hours and patience is important. Figuring out when a breakup is about to happen is one of the most debated topics in auroral physics. Bz switching from south to north is a likely sign of this, and there is about an hour\u2019s travel time needed for that Bz impact to reach Earth. Seeing auroral <a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/blog.aurorasaurus.org\/?p=398\">beads<\/a> is another very good indicator that a breakup is imminent within a few minutes.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Sometimes the bucket leaks<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Sometimes there is already some aurora visible, but it is diffuse, misty, and featureless. This can indicate a state of \u201csteady magnetospheric convection\u201d or \u201cSMC\u201d. In this case, energy is flowing into the system but dissipating instead of building up, like water in a leaky bucket.&nbsp;<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-5.png\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"585\" src=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-5-1024x585.png\" alt=\"A diagram reads &quot;a leaky system takes longer to fill all the way up&quot; and shows a leaky bucket being filled at a spigot. \" class=\"wp-image-2430\" style=\"aspect-ratio:1.750467539406893;width:378px;height:auto\" srcset=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-5-1024x585.png 1024w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-5-300x171.png 300w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-5-768x439.png 768w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-5.png 1070w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">SMC can come into play in several situations, but typically happens when Bz is persistently southward for much longer than an hour. SMC can last for 4-6 hours and feel like an excessively long growth phase. It\u2019s a perfect opportunity for practice, though. While the arc is slowly simmering in the sky, it gives an aurora chaser plenty of time to do photography test shots and to find a good composition. That way, when the breakup phase finally kicks off, the chaser is fully prepared.&nbsp;<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image.jpeg\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-1024x576.jpeg\" alt=\"Calm, soft green aurora floats over a body of water. \" class=\"wp-image-2425\" srcset=\"https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-1024x576.jpeg 1024w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-300x169.jpeg 300w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-768x432.jpeg 768w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image-1536x864.jpeg 1536w, https:\/\/blog.aurorasaurus.org\/wp-content\/uploads\/2026\/06\/image.jpeg 1920w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Isle Royale webcam, northern Michigan, July 4, 2025. Credit: US National Park Service. On this night, the aurora looked very still, like a growth phase arc, and did not develop for several hours (<a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/ui.adsabs.harvard.edu\/scan\/manifest\/1996SSRv...75..551S\">Sergeev et al., 1996<\/a>).<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Patience is key<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The aurora is driven by a complex system of matter, magnetism, and energy out in space, and is notoriously hard to predict. Being able to recognize the <a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/blog.aurorasaurus.org\/?p=2158\">phases of a substorm<\/a> and understanding the process of our celestial \u201cbucket\u201d filling can help to set expectations for an aurora chase. Sometimes it may take hours for an aurora to build\u2014a great opportunity for a cup of coffee, a chat with a friend, or a timelapse photo of the stars.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In addition, when scientists talk about substorms they tend to refer to everyday, high-latitude aurora caused by normal solar wind. Auroras from larger space weather events like <a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https:\/\/blog.aurorasaurus.org\/?p=2407\">coronal mass ejections and fast solar wind<\/a> can sometimes evolve in a similar pattern like substorms, but they can also behave in surprising ways that don\u2019t follow the same pattern. One of the reasons the dataset you help create with Aurorasaurus is so valuable is that it helps document both large and small events and the times when the aurora might (briefly) dance at lower latitudes. Together, we can learn more about this fascinating system!<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>by Tanya Melnik and Laura Edson&nbsp; The aurora follows a \u201clife cycle\u201d called a substorm. We know the feeling of waiting for the most dynamic part of the substorm to light the sky with green and red ribbons, but sometimes it seems to take forever. In this post we\u2019ll go over a couple of reasons&hellip;&nbsp;<a href=\"https:\/\/blog.aurorasaurus.org\/?p=2423\" rel=\"bookmark\">Read More &raquo;<span class=\"screen-reader-text\">Staying cool with aurora science<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":2425,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"rop_custom_images_group":[],"rop_custom_messages_group":[],"rop_publish_now":"yes","rop_publish_now_accounts":[],"rop_publish_now_history":[],"rop_publish_now_status":"pending","neve_meta_sidebar":"","neve_meta_container":"","neve_meta_enable_content_width":"","neve_meta_content_width":0,"neve_meta_title_alignment":"","neve_meta_author_avatar":"","neve_post_elements_order":"[\"title\",\"meta\",\"content\",\"tags\",\"comments\"]","neve_meta_disable_header":"","neve_meta_disable_footer":"","neve_meta_disable_title":"","footnotes":""},"categories":[24,7,12],"tags":[20,21,23,28],"class_list":["post-2423","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-citizen-science","category-education","category-understanding-the-aurora","tag-auroras","tag-citizen-science","tag-northern-lights","tag-science"],"_links":{"self":[{"href":"https:\/\/blog.aurorasaurus.org\/index.php?rest_route=\/wp\/v2\/posts\/2423","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.aurorasaurus.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.aurorasaurus.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.aurorasaurus.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.aurorasaurus.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2423"}],"version-history":[{"count":0,"href":"https:\/\/blog.aurorasaurus.org\/index.php?rest_route=\/wp\/v2\/posts\/2423\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blog.aurorasaurus.org\/index.php?rest_route=\/wp\/v2\/media\/2425"}],"wp:attachment":[{"href":"https:\/\/blog.aurorasaurus.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2423"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.aurorasaurus.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2423"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.aurorasaurus.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2423"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}