Uranus is Getting Colder and Now We Know Why

This zoomed-in image of Uranus, captured by Webb’s Near-Infrared Camera (NIRCam) Feb. 6, 2023, reveals stunning views of the planet’s rings. The planet's upper atmosphere has been cooling for decades, New research has an explanation. Credit: NASA, ESA, CSA, STScI IMAGE PROCESSING: Joseph DePasquale (STScI).

Uranus is an oddball among the Solar System’s planets. While most planets’ axis of rotation is perpendicular to their orbital plane, Uranus has an extreme tilt angle of 98 degrees. It’s flopped over on its side, likely from an ancient collision. It also has a retrograde orbit, opposite of the other planets.

The ice giant also has an unusual relationship with the Sun that sets it apart from other planets.

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The Sun Has Reached Its Solar Maximum and it Could Last for One Year

These extreme UV light images from the Solar Dynamics Observatory shows the Sun at solar minimum (left, Dec. 2019) compared to the current solar maximum. Image Credit: NASA/SDO

For most of human history, the Sun appeared stable. It was a stoic stellar presence, going about its business fusing hydrogen into helium beyond our awareness and helping Earth remain habitable. But in our modern technological age, that facade fell away.

We now know that the Sun is governed by its powerful magnetic fields, and as these fields cycle through their changes, the Sun becomes more active. Right now, according to NASA, the Sun is at its solar maximum, a time of increased activity.

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High-Resolution Images of the Sun Show How Flares Impact the Solar Atmosphere

A solar flare erupts on the Sun. Credit: NASA/GSFC/SDO

Solar flares are a fascinating thing and have a profound effect on what astronomers refer to as “space weather.” These events vary with the Sun’s 11-year solar cycle, releasing immense amounts of radiation across the electromagnetic spectrum (from extreme ultraviolet to X-rays) into space. The effects of flares have been observed since time immemorial, which include aurorae at high latitudes (Aurora Borealis and Australis), but have only been the subject of study and prediction for about a century and a half. Still, there is much that remains unknown about these dramatic events.

For instance, flares are known to affect the Sun’s atmosphere, from the visible surface (photosphere) to its outermost layer (corona). However, there are still questions about how these events influence the lower layers of the atmosphere. In a recent study led by the University of Colorado, Boulder, a team of researchers documented the rotation of two very small sunspots of the Sun’s surface (pores) using the Daniel K. Inouye Solar Telescope (DKIST) at Mauna Kea. These pores were linked to a less powerful flare and moved in a way that has never been observed, suggesting that the dynamics of the Sun’s atmosphere are more complex than previously thought.

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Life Might Thrive on the Surface of Earth for an Extra Billion Years

This view of Earth from space is a fusion of science and art, drawing on data from multiple satellite missions and the talents of NASA scientists and graphic artists. This image originally appeared in the NASA Earth Observatory story Twin Blue Marbles. Image Credits: NASA images by Reto Stöckli, based on data from NASA and NOAA.

The Sun is midway through its life of fusion. It’s about five billion years old, and though its life is far from over, it will undergo some pronounced changes as it ages. Over the next billion years, the Sun will continue to brighten.

That means things will change here on Earth.

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Groundbreaking New Maps of the Sun’s Coronal Magnetic Fields

The Daniel K. Inouye Solar Telescope has mapped the magnetic field of the Sun's corona for the first time. The corona is the source of most space weather, and this map will help scientists better understand the corona, space weather and other stars. Image Credit: Schad et al. 2024.

If you enjoyed this summer’s display of aurora borealis, thank the Sun’s corona. The corona is the Sun’s outer layer and is the source of most space weather, including aurorae. The aurora borealis are benign light shows, but not all space weather produces such harmless displays; some of it is dangerous and destructive.

In an effort to understand space weather and the solar corona, the National Science Foundation aimed the world’s most powerful solar telescope, the Daniel K. Inouye Solar Telescope, at the corona to map its magnetic fields.

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Coronal Loops-Digital Art Combination Captures Power of the Sun, Rendered by Andrew McCarthy

A composite image comprised of the Sun's surface, corona, and digitally-added coronal loops rendered by Andrew McCarthy. (Credit: Andrew McCarthy)

Our Sun is one of the most fascinating objects in the universe and photographing it with specialized equipment to capture its splendor and beauty has become increasingly more common around the world. This is most evident with the work obtained by renowned astrophotographer, Andrew McCarthy (@AJamesMcCarthy), who owns Cosmic Background Studios in Florence, Arizona.

On July 27, 2024, McCarthy posted an image of the Sun on X (formerly known as Twitter) taken with his specialized equipment designed to safely photograph our life-giving star, which revealed active coronal loops and plasma within the solar chromosphere that are some of the many intriguing features of the Sun. However, McCarthy is quick to mention in his post that this image isn’t entirely genuine, but a combination of several attributes.

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Why is the Sun’s Corona So Hot? One Hypothesis Down, Many to Go

Illustration of NASA’s Parker Solar Probe flying through a magnetic switchback from the Sun, with scientists still debating the origin of switchbacks within the Sun. (Credit: Adriana Manrique Gutierrez/NASA’s Goddard Space Flight Center)

The temperature of the Sun’s corona is a minimum of 100 times hotter than the Sun’s surface, despite the corona being far less dense and extending millions of miles from the Sun’s surface, as well. But why is this? Now, a recent study published in The Astrophysical Journal could eliminate a longstanding hypothesis regarding the processes responsible for the corona’s extreme heat, which could help them better understand the Sun’s internal processes. This study holds the potential to help scientists gain greater insight into the formation and evolution of our Sun, which could lead to better understanding stars throughout the universe, as well.

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Kepler Sketched the Sun in 1607. Astronomers Pinpointed the Solar Cycle

The earliest datable sunspot drawings based on Johannes Kepler's solar observations with camera obscura in May 1607.

Johannes Kepler is probably most well known for developing the laws of planetary motion. He was also a keen solar observer and in 1607 made some wonderful observations of our nearest star using a camera obscura. His drawings were wonderfully precise and enabled astronomers to pinpoint where the Sun was in its 11-year cycle. Having taken into account Kepler’s location and the location of sunspots, a team of researchers have identified the Sun was nearing the end of solar cycle-13.

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Solar Flares and Solar Magnetic Reconnection Get New Spotlight in Two Blazing Studies

Image of a solar flare (bright flash) obtained by NASA’s Solar Dynamics Observatory on Oct. 2, 2014, with a burst of solar material erupting being observed just to the right of the solar flare. (Credit: NASA/SDO)

Two recent studies published in The Astrophysical Journal discuss findings regarding solar flare properties and a new classification index and the Sun’s magnetic field, specifically what’s called solar magnetic reconnection. These studies hold the potential to help researchers better understand the internal processes of the Sun, specifically pertaining to solar flare activity and space weather. Here, Universe Today discusses these two studies with both lead authors regarding the motivation behind the studies, significant results, and implications on our understanding regarding solar flares and space weather.

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Seeing Both Sides of the Sun at the Same Time

Solar Orbiter's view of a solar outburst from AR3664 on May 21st, 2024. The views are in two different wavelengths of ultraviolet light. Courtesy: ESA & NASA/Solar Orbiter/EUI Team
Solar Orbiter's view of a solar outburst from AR3664 on May 21st, 2024. The views are in two different wavelengths of ultraviolet light. Courtesy: ESA & NASA/Solar Orbiter/EUI Team

As everybody who saw May’s spectacular auroral displays knows, the Sun is in its most active period in 11 years. The active region sunspot group that unleased the giant X-class flare rotated around the Sun, away from our direct view. But, that isn’t keeping the Solar Orbiter from spotting what’s happening with it and other active regions as they travel around on the Sun.

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