Ashley Strickland, CNN
Fri, 14 June 2024
When the sun unleashed an extreme solar storm and hit Mars in May, it engulfed the red planet with auroras and an influx of charged particles and radiation, according to NASA.
The sun has been showcasing more activity over the past year as it nears the peak of its 11-year cycle, called solar maximum, which is predicted to occur later this year.
Within recent months, there has been a spike in solar activity, such as X-class flares, the strongest of solar flares, and coronal mass ejections, or large clouds of ionized gas called plasma and magnetic fields that erupt from the sun’s outer atmosphere.
Solar storms that reached Earth in May sparked colorful auroras that danced in the skies over areas that rarely experience them, such as Northern California and Alabama.
The storms originated from a massive cluster of sunspots that happened to face Earth. Then, that sunspot cluster rotated in the direction of Earth’s cosmic neighbor: Mars.
Astronomers used the plethora of orbiters encircling the red planet, as well as rovers driving across its surface, to capture the impacts of a solar storm on Mars firsthand — and to understand better what kind of radiation levels the first astronauts on the red planet may experience in the future.
Solar radiation hits Mars
The most extreme storm occurred on May 20 after an X12 flare released from the sun, according to data collected by the Solar Orbiter spacecraft currently studying the sun.
The massive flare sent X-rays and gamma rays hurtling toward Mars, and a coronal mass ejection released quickly on the heels of the flare, flinging charged particles in the direction of the red planet.
The X-rays and gamma rays traveled at the speed of light and reached Mars first, followed by the charged particles within tens of minutes, according to scientists tracking the activity from NASA’s Moon to Mars Space Weather Analysis Office at the Goddard Space Flight Center in Greenbelt, Maryland.
The Curiosity rover, currently exploring Gale Crater just south of the Martian equator, took black-and-white images using its navigation cameras during the solar storm. White streaks resembling snow, which can be seen in the images, are the result of charged particles hitting Curiosity’s cameras, according to NASA.
The energy from the solar particles was so strong that the star camera aboard the Mars Odyssey orbiter, which helps orient the probe as it circles the planet, momentarily shut down. Fortunately, the spacecraft was able to turn the camera back on within an hour. The last time Odyssey faced such extreme solar behavior was during the solar maximum of 2003, when an X45 flare fried the orbiter’s radiation detector.
Fifty-seven images make up this selfie taken by the Curiosity Mars rover at one of its drill sites in January 2019. - NASA/Caltech-JPL/MSSS
Meanwhile, Curiosity used its Radiation Assessment Detector, or RAD, to measure the amount of radiation hitting the planet during the storm. An astronaut standing next to the rover would have experienced radiation equal to 30 chest X-rays, which isn’t deadly, but is the largest such surge of radiation that the rover’s instrument has measured since landing nearly 12 years ago.
Understanding the peak radiation that astronauts may experience on the red planet helps scientists to plan how to protect those on crewed exploration to Mars in the future.
“Cliffsides or lava tubes would provide additional shielding for an astronaut from such an event. In Mars orbit or deep space, the dose rate would be significantly more,” said Don Hassler, RAD principal investigator at the Southwest Research Institute’s Solar System Science and Exploration Division in Boulder, Colorado, in a statement. “I wouldn’t be surprised if this active region on the Sun continues to erupt, meaning even more solar storms at both Earth and Mars over the coming weeks.”
Auroras on the red planet
The MAVEN orbiter, short for Mars Atmosphere and Volatile EvolutioN, had an aerial view of auroras dancing in ultraviolet light over Mars during the solar storm. The orbiter launched to Mars in 2013 to study how the red planet has lost its atmosphere over time and how space weather generated by the sun interacts with the upper Martian atmosphere.
But these auroras appear much different from the northern lights, or aurora borealis, and southern lights, or aurora australis, that occur on Earth.
When the energized particles from coronal mass ejections reach Earth’s magnetic field, they interact with gases in the atmosphere to create different colored lights in the sky, specifically near its poles.
But Mars lost its magnetic field billions of years ago, which means the planet has no shield from incoming energized solar particles. So when the particles hit Mars’ thin atmosphere, the reaction results in planet-engulfing auroras.
“Given Mars’ lack of a global magnetic field, Martian aurorae are not concentrated at the poles as they are on Earth, but instead appear as a ‘global diffuse aurora’ that are associated with Mars’ ancient, magnetized crust,” wrote Deborah Padgett, Operational Product Generation Subsystem task lead at NASA’s Jet Propulsion Laboratory in Pasadena, California, in the space agency’s Curiosity rover blog.
Future astronauts may be able to witness these Martian light shows one day, according to NASA.
By tracing the data from multiple Martian missions, scientists were able to watch how the solar storm unfolded.
“This was the largest solar energetic particle event that MAVEN has ever seen,” said MAVEN Space Weather Lead Christina Lee of the University of California, Berkeley’s Space Sciences Laboratory, in a statement. “There have been several solar events in past weeks, so we were seeing wave after wave of particles hitting Mars.
Space weather forecasting needs an upgrade to protect future Artemis astronauts
Lulu Zhao, University of Michigan
Thu, 13 June 2024
The Sun can send out eruptions of energetic particles. NASA/SDO via AP
NASA has set its sights on the Moon, aiming to send astronauts back to the lunar surface by 2026 and establish a long-term presence there by the 2030s. But the Moon isn’t exactly a habitable place for people.
Cosmic rays from distant stars and galaxies and solar energetic particles from the Sun bombard the surface, and exposure to these particles can pose a risk to human health.
Both galactic cosmic rays and solar energetic particles, are high-energy particles that travel close to the speed of light.
While galactic cosmic radiation trickles toward the Moon in a relatively steady stream, energetic particles can come from the Sun in big bursts. These particles can penetrate human flesh and increase the risk of cancer.
Earth has a magnetic field that provides a shield against high-energy particles from space. But the Moon doesn’t have a magnetic field, leaving its surface vulnerable to bombardment by these particles.
During a large solar energetic particle event, the radiation dosage an astronaut receives inside a space suit could exceed 1,000 times the dosage someone on Earth receives. That would exceed an astronaut’s recommended lifetime limit by 10 times.
NASA’s Artemis program, which began in 2017, intends to reestablish a human presence on the Moon for the first time since 1972. My colleagues and I at the University of Michigan’s CLEAR center, the Center for All-Clear SEP Forecast, are working on predicting these particle ejections from the Sun. Forecasting these events may help protect future Artemis crew members.
With Artemis, NASA plans to return humans to the lunar surface. AP Photo/Michael Wyke
An 11-year solar cycle
The Moon is facing dangerous levels of radiation in 2024, since the Sun is approaching the maximum point in its 11-year solar cycle. This cycle is driven by the Sun’s magnetic field, whose total strength changes dramatically every 11 years. When the Sun approaches its maximum activity, as many as 20 large solar energetic particle events can happen each year.
Both solar flares, which are sudden eruptions of electromagnetic radiation from the Sun, and coronal mass ejections, which are expulsions of a large amount of matter and magnetic fields from the Sun, can produce energetic particles.
The Sun is expected to reach its solar maximum in 2026, the target launch time for the Artemis III mission, which will land an astronaut crew on the Moon’s surface.
While researchers can follow the Sun’s cycle and predict trends, it’s difficult to guess when exactly each solar energetic particle event will occur, and how intense each event will be. Future astronauts on the Moon will need a warning system that predicts these events more precisely before they happen.
Forecasting solar events
In 2023, NASA funded a five-year space weather center of excellence called CLEAR, which aims to forecast the probability and intensity of solar energetic particle events.
Right now, forecasters at the National Oceanic and Atmospheric Administration Space Weather Prediction Center, the center that tracks solar events, can’t issue a warning for an incoming solar energetic particle event until they actually detect a solar flare or a coronal mass ejection. They detect these by looking at the Sun’s atmosphere and measuring X-rays that flow from the Sun.
Once a forecaster detects a solar flare or a coronal mass ejection, the high-energy particles usually arrive to Earth in less than an hour. But astronauts on the Moon’s surface would need more time than that to seek shelter. My team at CLEAR wants to predict solar flares and coronal mass ejections before they happen.
The solar magnetic field is incredibly complex and can change throughout the solar cycle. On the left, the magnetic field has two poles and looks relatively simple, though on the right, later in the solar cycle, the magnetic field has changed. When the solar magnetic field looks like the illustration on the right, solar flares and coronal mass ejections are more common. NASA’s Goddard Space Flight Center/Bridgman, CC BYMore
While scientists don’t totally understand what causes these solar events, they know that the Sun’s magnetic field is one of the key drivers. Specifically, they’re studying the strength and complexity of the magnetic field in certain regions on the Sun’s surface.
At the CLEAR center, we will monitor the Sun’s magnetic field using measurements from both ground-based and space-based telescopes and build machine learning models that predict solar events – hopefully more than 24 hours before they happen.
With the forecast framework developed at CLEAR, we also hope to predict when the particle flux falls back to a safe level. That way, we’ll be able to tell the astronauts when it’s safe to leave their shelter and continue their work on the lunar surface.
This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Lulu Zhao, University of Michigan
Read more:
Solar storms can destroy satellites with ease – a space weather expert explains the science
Earth’s magnetic field protects life on Earth from radiation, but it can move, and the magnetic poles can even flip
Solar storm knocks out farmers’ high-tech tractors – an electrical engineer explains how a larger storm could take down the power grid and the internet
Lulu Zhao serves as the principle investigator of CLEAR at the University of Michigan, which receives funding from NASA.
It’s one of the biggest puzzles in cosmology. Why two different methods used to calculate the rate at which the universe is expanding don’t produce the same result. Known as the Hubble tension, the enigma suggests that there could be something wrong with the standard model of cosmology used to explain the forces in the universe.
Now, recent observations using the new James Webb Space Telescope (JWST) are shaking up the debate on how close the mystery is to being resolved.
In this episode of The Conversation Weekly podcast, two professors of astronomy explain why the Hubble tension matters so much for our understanding of the universe.
In February, the Nobel prize-winning physicist Adam Reiss, published a new paper. It said that new observations of far-away stars using the JWST matched those obtained by the Hubble Space Telescope.
These stars, called Cepheids, are commonly used in one method of calculating the rate at which the universe is expanding. Known as the local distance ladder, or cosmic distance ladder, this method has been around since observations first made by Edwin Hubble himself in 1929. And it generally produces a rate of expansion of around 73km per second per mega parsec.
But a second method, using predictions of the cosmic microwave background radiation left over by the Big Bang, has constantly arrived at a different number for the rate of expansion of the universe: 67km per second per mega parsec.
Reiss said that when the new data confirmed the earlier observations from the Hubble Space Telescope, the gap between the numbers remains unresolved. “What remains is the real and exciting possibility that we have misunderstood the universe,” he said.
A few months later, however, more data from the JWST, presented by Wendy Freedman, a physicist at the University of Chicago, using observations from a different set of stars, arrived at 69km per second per mega parsec, a number closer to the cosmic microwave background figure of 67. Freedman is excited that the numbers seem to be converging.
Listen to The Conversation’s podcast series Great Mysteries of Physics for more about the greatest mysteries facing physicists today – and the radical proposals for solving them. Hosted by Miriam Frankel it features interviews with some of the worlds leading scientists including Sean Carroll, Sabine Hossenfelder and Jim Al-Khalili.
Vicent Martínez and Bernard Jones are fascinated by the Hubble tension. Jones is an emeritus professor of astronomy at the University of Groningen in the Netherlands. Martínez, his former student, is now a professor of astronomy and astrophysics at the University of València in Spain.
“The fundamental basis of science, what distinguishes science from science fiction, is our ability to verify the information we are getting,” explains Jones.
That’s why Martinez says the mystery of the Hubble tension is still driving people to:
Research and imagine experiments and organise huge projects with the complicated observation of the cosmos in order to understand what’s going on. At the end, this will affect your idea of the whole universe and probably you will need to change some fundamental ingredient of your cosmological model.
Martinez and Jones have just written a book, along with their co-author Virginia Trimble, about moments in history when scientists realised they’d got something very wrong, and had to readjust their way of thinking. Martínez thinks this could happen again with the Hubble tension:
It could happen that, for example, a new theory of gravity could solve the problem of dark energy or dark matter. We have to be open to those ideas.
Listen to Bernard Jones and Vicent Martínez talk more about the Hubble tension, and how it fits in the wider history of science, on The Conversation Weekly podcast. The episode also features an introduction from Lorena Sánchez, science editor at The Conversation in Spain.
A transcript of this episode will be available shortly.
This episode of The Conversation Weekly was written and produced by Katie Flood, with assistance from Mend Mariwany. Gemma Ware was the executive producer. Sound design was by Eloise Stevens, and our theme music is by Neeta Sarl. Stephen Khan is our global executive editor and Soraya Nandy helps with our transcripts.
You can find us on Instagram at theconversationdotcom or via email. You can also subscribe to The Conversation’s free daily email here.
Listen to The Conversation Weekly via any of the apps listed above, download it directly via our RSS feed or find out how else to listen here.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Vicent J. Martínez receives funding from the Ministerio de Ciencia, Innovación y Universidades (MICIU)—Agencia Estatal de Investigación y de la Conselleria d’Educació, Universitats i Ocupació de la Generalitat Valenciana. Bernard J.T. Jones does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
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