How Solar Explosions Unleash X-Ray Auroras on Mercury
Every 11 years,a href="https://www.syfy.com/syfy-wire/welcome-cycle-25-a-new-solar-magnetic-cycle-has-begun" target="_blank" rel="noreferrer noopener"the Sun gets a little stir crazy/a and throws a temper tantrum. We’ve been tracking those cycles for the better part of three centuries and we’re currently creeping up on Solar Maximum of Solar Cycle 25. Solar Max is characterized by an uptick in sunspots, a href="https://www.syfy.com/syfy-wire/topic/solar-flares" target="_blank" rel="noreferrer noopener"solar flares/a, and a href="https://www.syfy.com/syfy-wire/aurora-alert-strong-cme-lights-up-the-night-sky" target="_blank" rel="noreferrer noopener"coronal mass ejections/a (CMEs). During Solar Max, eruptions of charged solar particles become more powerful and more frequent./p pIn the disaster flick emSolar Attack,/emone such CME threatens to light the sky on fire and wipe out all life on Earth. In the real world, we’re protected from the worst effects of solar eruptions by the planet’s magnetic field, and CMEs mostly make themselves known by more intense and more frequent a href="https://www.syfy.com/syfy-wire/what-are-the-northern-and-southern-lights-really" target="_blank" rel="noreferrer noopener"auroras/a. As charged solar particles bombard the Earth and get tangled up in the magnetosphere, they interact with molecules in the upper atmosphere and shine like cosmic glow sticks which we call the Northern (or Southern) Lights. While Earth’s auroras are the most famous and the easiest to see, we’re not the only world getting lit up by solar eruptions./p h2Solar Explosions Trigger Strange Auroras on Mercury/h2 pOn March 10, 2024, a massive solar eruption struck Mercury, likely setting off intense and unusual auroral activity on the surface. a href="https://www.spaceweather.com/archive.php?view=1day=10month=03year=2024" target="_blank" rel="noreferrer noopener"Space Weather reported/a that a large magnetic filament broke away from the Sun on March 9 and 10. NASA’s Solar Dynamics Observatory (DSO) – a space-based observatory in geosynchronous orbit around the Earth – caught an image of the filament breaking away and estimated its size at 310,000 miles (500,000 kilometers) across./p pOver the next several hours, that CME raced across the narrow gap in space and smashed into the inner planet’s surface. Because of its proximity to the Sun, Mercury is no stranger to solar bombardment, taking the brunt of solar temper tantrums, and those charged particles do some weird stuff on Mercury./p pstrongFor More on Solar Storms:bra href="https://www.syfy.com/syfy-wire/earth-narrowly-missed-a-solar-storm-apocalypse-in-2012" target="_blank" rel="noreferrer noopener"Earth Narrowly Missed a Solar Storm “Apocalypse” in 2012/abra href="https://www.syfy.com/syfy-wire/what-are-the-northern-and-southern-lights-really" target="_blank" rel="noreferrer noopener"What Are the Northern (and Southern) Lights, Really?/abra href="https://www.syfy.com/syfy-wire/watch-nasas-parker-solar-probe-fly-through-a-coronal-mass-ejection" target="_blank" rel="noreferrer noopener"Watch NASA’s Parker Solar Probe Fly Through a Coronal Mass Ejection/a/strong/p div data-embed-button="media" data-entity-embed-display="view_mode:media.embed" data-entity-embed-display-settings="[]" data-entity-type="media" data-entity-uuid="0e33be5d-db52-4bde-b7bf-10ea7e31849a" data-langcode="en" class="embedded-entity"div class="media__image" style="max-width:862px" div class="media__image-wrapper" div div img loading="lazy" decoding="async" fetchpriority="low" src="https://www.syfy.com/sites/syfy/files/styles/scale_862/public/2022/03/mercury_nasa.jpg" width="862" height="485" alt="An image of Mercury that represents chemical, mineralogical, and physical differences between the rocks that make up Mercury's surface with colors spanning between blue, brown, and yellow." typeof="foaf:Image" /div /div /div div class="media__metadata" div class="media__metadata-wrapper" span class="media__caption" This colorful view of Mercury was produced by using images from the color base map imaging campaign during MESSENGER's primary mission. These colors are not what Mercury would look like to the human eye, but rather the colors enhance the chemical, mineralogical, and physical differences between the rocks that make up Mercury's surface. /span span class="media__credit"Photo: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington /span /div /div /div /div pIn 2023, researchers working with the BepiColombo spacecraft uncovered new details about Mercury’s unusual auroras. During a flyby, the spacecraft got within 125 miles (200 kilometers) of Mercury’s surface. Instruments aboard the spacecraft measured charged particles from the Sun and Mercury’s magnetosphere. They found that the tiny planet’s magnetic shield is compressed where the solar wind smashes into it and they also explained how that impacts Mercurian auroras in a paper a href="https://www.nature.com/articles/s41467-023-39565-4" target="_blank" rel="noreferrer noopener"published in the journal emNature Communications/em/a./p p“For the first time, we have witnessed how electrons are accelerated in Mercury’s magnetosphere and precipitated onto the planet's surface. While Mercury’s magnetosphere is much smaller than Earth’s and has a different structure and dynamics, we have confirmation that the mechanism that generates aurorae is the same throughout the Solar System,” said lead author Sae Aizawa, a href="https://www.eurekalert.org/news-releases/995903" target="_blank" rel="noreferrer noopener"in a statement/a./p pOn Earth, CME’s hit the magnetosphere and the atmosphere and trigger gorgeous light shows high up in the sky. On Mercury, all of that intense solar activity and a lower gravitational foothold robbed Mercury of its atmosphere long ago. Today, charged particles from the Sun hit the planet directly. They move in toward the planet, barely impeded by the planet’s relatively small magnetic field, and rain down on the bare ground. When that happens, they slow down so rapidly that they emit a href="https://www.syfy.com/syfy-wire/topic/x-rays" target="_blank" rel="noreferrer noopener"X-ray/a energy and create an auroral glow at the site of impact. On Mercury, the aurora doesn’t wave overhead, it glows all around you. Of course, you wouldn’t want to be standing there when it happens./p
