A LULL IN THE SOLAR WIND: Earth is passing through a broad gulf between streams of high-speed solar wind. This should keep geomagnetic activity low until the solar wind quickens again, possibly on June 12th or 13th. Until then, any auroras will come as a surprise. Free: Aurora Alerts.
MARS OUTSHINES SIRIUS: It's official. Mars is now brighter than any star in the sky. This week, the Red Planet surpassed Sirius in apparent luminosity. If you wake up before dawn, you can't help noticing Mars burning through the morning twilight with a distinctive orange glow. This recent picture from Alan Dyer of Gleichen, Alberta, shows what to expect:
What's happening? Earth and Mars are converging for a close encounter--the best one in 15 years. On July 27th, Mars will be at opposition. Oppositions of Mars happen roughly every 2 years, but this one is special. It is a "perihelic opposition." Mars will be near perihelion, its closest approach to the sun. Perihelic oppositions also bring Mars extra-close to Earth.
The last time this happened was on Aug. 27, 2003, when Mars famously made its closest approach to Earth in almost 60,000 years. Around the world, people organized "Mars parties" to celebrate the extraordinary size and brightness of the Red Planet. This July will be almost as good with Mars only a few percent farther away than it was during its historic encounter 15 years ago. Between now and then, Mars will triple in brightness, outshining even the giant planet Jupiter. Stay tuned for that!
FATHER'S DAY SPECIAL: What do you get for the Dad who has everything? He probably doesn't have this: A 3D Moon globe laser-etched inside a crystal cube. And, oh yes, it has been to the edge of space:
The students of Earth to Sky Calculus flew a payload-full of these unique cubes to the stratosphere on June 3rd. You can have one for $149.95. They're selling them as a fund-raiser for their cosmic ray ballooning program.
Each Moon-cube comes with a unique gift card showing the item floating at the top of Earth's atmosphere. The interior of the card tells the story of the flight and confirms that this gift has been to the edge of space and back again. Dad-satisfaction guaranteed.
Far Out Gifts: Earth to Sky Store
All proceeds support hands-on STEM education
GLOBAL COSMIC RADIATION MEASUREMENTS: For the past two years, Spaceweather.com and the students of Earth to Sky Calculus have been traveling around the world, launching cosmic ray balloons to map our planet's radiation environment. Our sensors travel from ground level to the stratosphere and bring their data back to Earth by parachute. Here is a plot showing radiation vs. altitude in Norway, Chile, Mexico, and selected locations in the USA:
Note: Data from Sweden and several other US states are omitted for the clarity of the plot.
We're about to add a new country to the list: New Zealand. On June 18th, a team of students from Earth to Sky is traveling to New Zealand's north island to launch 3 cosmic ray balloons in only 10 days. Soon, we will know more about cosmic rays above Earth's 8th continent.
Cosmic rays are, essentially, the subatomic debris of dying stars, accelerated to nearly light speed by supernova explosions. They travel across space and approach Earth from all directions, peppering our planet 24/7. When cosmic rays crash into Earth's atmosphere, they produce a spray of secondary particles and photons that is most intense at the entrance to the stratosphere. This secondary spray is what we measure.
The purpose of our mapping project is to study how well Earth's atmosphere and magnetic field protects us from cosmic rays. As the plot shows, the shielding is uneven. More radiation gets through to the poles (e.g., Norway) and less radiation penetrates near the equator (e.g., Mexico).
But there's more to the story. Our launch sites in Chile and California are equidistant from the equator, yet their radiation profiles are sharply different. Chile is on the verge of the South Atlantic Anomaly, which almost surely distorts the radiation field there. Our flights over New Zealand may shed some light on this, because our launch sites in New Zealand will be the same distance from the equator as the sites in Chile. Stay tuned!
Technical note: The radiation sensors onboard our helium balloons detect X-rays and gamma-rays in the energy range 10 keV to 20 MeV. These energies span the range of medical X-ray machines and airport security scanners.