SpaceWeather.com Archive — Tue, Nov 19, 2024

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A NEW SOURCE OF SOLAR FLARES: Yesterday, the sun produced nine M-class solar flares--a sudden uptick in solar activity caused mainly by new sunspot AR3901. The sunspot is turning toward Earth, so future flares will be geoeffective if it remains active. Solar flare alerts: SMS Tex t

ATMOSPHERIC RADIATION IS PLUMMETING: The number of galactic cosmic rays in our atmosphere just reached a 10-year low. The sharp decline is shown in this dataset of more than 300 high-altitude balloon flights over California from 2015 to 2024:

According to the data, gathered by the students of Earth to Sky Calculus, atmospheric radiation has been dropping about 10% per year for the past three years, resulting in a nearly 1/3rd decrease overall. The decline isn't only in the stratosphere. It is also filtering down to aviation altitudes. This means air travelers are absorbing less radiation when they fly.

At first glance, this seems counterintuitive. NASA and NOAA recently announced that Solar Maximum has arrived, bringing solar activity to 10+ year high. So why is radiation decreasing?

Answer: We're not measuring radiation from the sun. This radiation comes from the Galaxy. Supernova explosions and other violent events fill the Milky Way with high energy particles. Called "galactic cosmic rays," these subatomic cannonballs penetrate the walls of spacecraft and pose a long-term health threat to astronauts. They're actually worse than solar flares.

An artist's concept of galactic cosmic rays hitting Earth. [Learn more]

When galactic cosmic rays hit the top of the atmosphere, they create a spray of secondary cosmic rays, which we measure using radiation sensors and balloons. "We" means Spaceweather.com and the students of Earth to Sky Calculus. It's a STEM program that started more than a decade ago, teaching kids how to do science and manage a DIY space program.

Galactic cosmic rays are decreasing because of Solar Maximum. Over the past few years, the sun's magnetic field has grown stronger and more complex as the solar cycle reaches its peak. This makes it harder for galactic cosmic rays to penetrate the solar system, and accounts for the decrease we have observed.

Who cares? Astronauts, obviously. The European Space Agency calls galactic cosmic rays "a show stopper" for Mars exploration. Air travelers are also affected. A 2018 Harvard study cited cosmic rays as a risk factor for cancer in flight crews.

At the moment, there is no sign of the decline slowing down. Stay tuned for more data as we continue to launch balloons into Solar Cycle 25.

Would you like to support our balloon program? Buy a Christmas gift from the Earth to Sky Store :)

BLACK FRIDAY AT THE EDGE OF SPACE: Christmas is coming. Are you looking for a far-out gift? Check out the Earth to Sky Store. It's filled with unique items that have flown to the edge of space onboard cosmic ray research balloons.

Carried aloft by giant helium balloons, these unique gifts have flown above 99.7% of Earth's atmosphere, experiencing space-like blasts of cosmic rays, extreme cold, and a wild ride parachuting back to Earth after the balloon explodes. Even Amazon doesn't carry items this far out.

Don't forget to enter coupon code "HANDOFAPOLLO" at checkout for a 10% Early Black Friday discount.

Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education

MANMADE NOCTILUCENT CLOUDS OVER TEXAS: When the Space Age began in the1950s, only Mother Nature made noctilucent clouds (NLCs). Now SpaceX does it, too. Anthony Griffith saw the rocket company's contribution rippling over Van Horn, Texas, before sunrise on Nov 18th:

"I've seen NLCs often in northern states and Europe, but never at such a low latitude," says Griffith. "I'm not sure if they're true NLCs or something else."

Answer: Something else.

Natural NLCs form above Earth's poles in summer when wisps of water vapor drift up to the edge of space, frosting specks of meteor dust. To see them, you usually have to travel to the Arctic.

SpaceX makes NLCs using rockets. Falcon 9 rocket engines emit a spray of watery exhaust as they exit Earth's atmosphere. That water mixes with meteor dust to create "rocket NLCs."

About 6 hours before Griffith saw the clouds over Texas, SpaceX launched a batch of 20 Starlink satellites from Vandenberg Space Force Base in California. Stephen Sullivan photographed the launch from Malibu:

Between launch in California and sunrise in Texas, the clouds drifted across the USA at latitudes near +30 degrees, thousands of miles below the Arctic Circle. NLCs aren't just a polar phenomenon any more. They can appear anywhere rockets go.