sun Archives

June 15, 2020June 15, 2020 by Paul M. Sutter

Scientists are much better at predicting when the Sun is going to become more active

A massive prominence erupts from the surface of the sun. Credit: NASA Goddard Space Flight Center

The sun constantly cycles between periods of activity and periods of inactivity, and a new technique allows scientists to better predict when things will start getting interesting.

May 27, 2020May 27, 2020 by Evan Gough

The Solar System Might Not Exist if There Wasn’t a Huge Galactic Collision with the Milky Way Billions of Years Ago

Artist's conception of a solar system in formation. It's likely that exoplanet formation around other stars proceeded similarly. Credit: NASA/FUSE/Lynette Cook

The Milky Way has a number of satellite galaxies; nearly 60 of them, depedending on how we define them. One of them, called the Sagittarius Dwarf Spheroidal Galaxy (Sgr d Sph), may have played a huge role when it comes to humans, our world and our little civilization. A collision between the Milky Way and the Sgr d Sph may have created the Solar System itself.

March 27, 2020March 28, 2020 by Paul M. Sutter

The heliosphere looks a lot weirder than we originally thought

A model of the heliosphere as imagined by new research. Yes, it looks like an ugly croissant. Image courtesy of Merav Opher, et. al

Every second of every day, our sun spits out a stream of tiny high-energy particles, known as the solar wind. This wind blows throughout the solar system, extending far beyond the orbits of the planets and out into interstellar space.

But the farther from the sun the wind gets, the more slowly it streams, changing from the raging torrent that the inner planets experience (strong enough to cause the aurora) into nothing more than an annoying drizzle. And far enough away – about twice the orbit of Neptune – it meets and mingles with all the random bits of energetic junk just floating around amongst the stars.

January 31, 2020January 31, 2020 by Evan Gough

Destructive Super Solar Storms Hit Us Every 25 Years Or So

A coronal mass ejection (CME) from the Sun on August 31, 2012, the event that caused a third ring to form in the Van Allen radiation belts. Credit: NASA

Solar storms powerful enough to wreak havoc on electronic equipment strike Earth every 25 years, according to a new study. And less powerful—yet still dangerous—storms occur every three years or so. This conclusion comes from a team of scientists from the the University of Warwick and the British Antarctic Survey.

These powerful storms can disrupt electronic equipment, including communication equipment, aviation equipment, power grids, and satellites.

November 12, 2019November 12, 2019 by Evan Gough

Satellites Watched Mercury’s Transit From Space, Confirming That Yes, the Sun Has At Least One Planet

Do you wonder how astronomers find all those exoplanets orbiting stars in distant solar systems?

Mostly they use the transit method. When a planet travels in between its star and an observer, the light from the star dims. That’s called a transit. If astronomers watch a planet transit its star a few times, they can confirm its orbital period. They can also start to understand other things about the planet, like its mass and density.

The planet Mercury just transited the Sun, giving us all an up close look at transits.

October 9, 2019October 9, 2019 by Evan Gough

Power Grids and Satellites Are More at Risk from Extreme Solar Storms Than We Thought

This visualization depicts what a coronal mass ejection might look like like as it interacts with the interplanetary medium and magnetic forces. Credit: NASA / Steele Hill

Exactly how dangerous are solar storms? Scientists think the Carrington Event was one of the most powerful ones to ever hit Earth. They also think that storms that powerful only happen every couple centuries or so. But a new study says we can expect more storms equally as strong, and more often.

September 5, 2019September 5, 2019 by Evan Gough

This Star Has Reached the End of its Life

This Picture of the Week from the NASA/ESA Hubble Space Telescope shows NGC 5307, a planetary nebula which lies about 10000 light years from Earth. It can be seen in the constellation Centaurus (The Centaur), which can be seen primarily in the southern hemisphere. A planetary nebula is the final stage of a Sun-like star. As such, planetary nebulae allow us a glimpse into the future of our own Solar System. A star like our Sun will, at the end of its life, transform into a red giant. Stars are sustained by the nuclear fusion that occurs in their core, which creates energy. The nuclear fusion processes constantly try to rip the star apart. Only the gravity of the star prevents this from happening. At the end of the red giant phase of a star, these forces become unbalanced. Without enough energy created by fusion, the core of the star collapses in on itself, while the surface layers are ejected outward. After that, all that remains of the star is what we see here: glowing outer layers surrounding a white dwarf star, the remnants of the red giant star’s core. This isn’t the end of this star’s evolution though — those outer layers are still moving and cooling. In just a few thousand years they will have dissipated, and all that will be left to see is the dimly glowing white dwarf.

About 10,000 light years away, in the constellation Centaurus, is a planetary nebula called NGC 5307. A planetary nebula is the remnant of a star like our Sun, when it has reached what can be described as the end of its life. This Hubble image of NGC 5307 not only makes you wonder about the star’s past, it makes you ponder the future of our very own Sun.

August 17, 2019August 17, 2019 by Evan Gough

When it Comes to Gamma Radiation, the Moon is Actually Brighter Than the Sun

NASA's Fermi Gamma-Ray Space Telescope captures the hellish glow of gamma rays coming from the Moon. Image Credit: NASA/DOE/Fermi LAT Collaboration

The eerie, hellish glow coming from the Moon may seem unreal in this image, since it’s invisible to our eyes. But instruments that detect gamma rays tell us it’s real. More than just a grainy, red picture, it’s a vivid reminder that there’s more going on than meets human eyes.

It’s also a reminder that any humans that visit the Moon need to be protected from this high-energy radiation.

February 5, 2019February 5, 2019 by Paul M. Sutter

How The Sun’s Scorching Corona Stays So Hot

We’ve got a mystery on our hands. The surface of the sun has a temperature of about 6,000 Kelvin – hot enough to make it glow bright, hot white. But the surface of the sun is not its last later, just like the surface of the Earth is not its outermost layer. The sun has a thin but extended atmosphere called the corona. And that corona has a temperature of a few million Kelvin.

How does the corona have such a higher temperature than the surface?

Like I said, a mystery.

January 31, 2019January 31, 2019 by David Dickinson

When Does the Sun Rise… Really?

Mercury Sunrise — A transit of Mercury at sunrise. Image credit and copyright: Alan Dyer.

It’s strange but true. We may not fully understand one of the simplest metrics in observational astronomy: just what time does the Sun rise… really?