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GEOMAGNETIC STORM PREDICTED: NOAA forecasters say there is a 70% chance of G1-class geomagnetic storms on June 27th when a stream of solar wind hits Earth's magnetic field. The gaseous material is flowing from a large, irregular hole in the sun's atmosphere. High latitude sky watchers should be alert for auroras, especially in the southern hemisphere where winter darkness favors visibility. Free: Aurora Alerts.
NOCTILUCENT TORNADO: In recent nights, noctilucent clouds (NLCs) have rippled across Europe from Scandinavia to the south of France. "We have been observing NLCs every night here in N. Ireland," reports Martin McKenna of Maghera in Co. Derry. "Their brightness and complexity have been getting more advanced since the solstice, with whirls and knots glowing electric blue above a yellow midnight sunset horizon." He observed this 'noctilucent tornado' on June 25th:
"It was amazing to watch," he says. "This area then morphed into an succession of dynamic shapes--a wedge, a funnel, angel wings, an electrified smoke ring, then a long rope tornado which reached towards the horizon."
What creates these forms? The answer is "gravity waves."
Gravity waves are, essentially, waves of pressure and temperature spawned by powerful storm systems. Gravity does not vary inside the waves; they get their name from the fact that gravity acts as a restoring force that tries to restore equilibrium to up-and-down moving air. Gravity waves can propagate all the way from Earth's surface up to the mesosphere, where they imprint themselves on the the forms of noctilucent clouds. When a sufficient number of gravity waves meet, they can interfere to produce all of the structures McKenna saw--plus many more.
Summer is the season for NLCs. Summertime wisps of water vapor rise to the top of Earth's atmosphere where they wrap themselves around specks of meteor smoke. Mesospheric winds gather the resulting ice crystals into noctilucent clouds
Realtime Noctilucent Cloud Photo Gallery
MYSTERIOUS TWINNED RAINBOW: Scientists have been studying rainbows for hundreds of years, since the 17th century when Isaac Newton first explained the colorful arcs. Yet after all these years, there is one rainbow scientists do not fully understand--the "twinned bow." Jan Curtis photographed this specimen on June 21st from Cheyenne, Wyoming:
"This rare 'twinned rainbow' was perhaps the brightest rainbow I've ever seen," says Curtis. "It followed on the tails of a extremely severe thunderstorm that fortunately passed just a few miles to my north."
"Several twinned bows have been imaged, mostly during heavy showers, but currently there is no agreed explanation for them," says atmospheric optics expert Les Cowley. "They might form from a mixture of water drops and ice spheres." Indeed, Curtis reports intense hail around the time of his sighting.
"A stronger possibility is that non-spherical raindrops produce one or both bows," Cowley adds. "Surface tension forces keep small raindrops fiercely spherical but as they fall large drops are flattened by air resistance or might even oscillate between flattened and elongated spheroids."
Another striking aspect of Curtis's image is the overall double structure of the rainbow--one rainbow on the inside, another on the outside. Such double rainbows are often seen and well understood. The splitting of the inner bow into twins added a dash of mystery to this otherwise common occurance.
Realtime Space Weather Photo Gallery
ONE RING TO RULE THE STRATOSPHERE: This week, the students of Earth to Sky Calculus are in New Zealand launching cosmic ray balloons over Earth's 8th continent. To pay for the helium, they launched a ring of power to the stratosphere. Here it is floating 33 km above the Sierra Nevada mountains of central California:
You can have one for $119.95. The students are selling these rings as a fundraiser for their trip. They are made of golden-colored tungsten and inscribed with the authentic Mordor script of the One Ring.
Buy one now, and we will fly it again for you over Hobbiton, located in the North Island of New Zealand where our cosmic ray balloons will be released. Just note "Please fly it again!" in the comments section at checkout.
Each golden ring comes with a greeting card showing the ring in flight and telling the story of its journey to the edge of space. Sales support the Earth to Sky Calculus cosmic ray ballooning program and hands-on STEM research.
Far Out Gifts: Earth to Sky Store
All proceeds support hands-on STEM education
Realtime Aurora Photo Gallery
Every night, a network of
NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.
On Jun. 26, 2018, the network reported 22 fireballs.
(20 sporadics, 1 Microscorpiid, 1 Northern June Aquilid)
In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]
Potentially Hazardous Asteroids (
PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding
new ones all the time.
On June 26, 2018 there were 1912 potentially hazardous asteroids.
 |
Recent & Upcoming Earth-asteroid encounters: | Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) |
| 2018 MJ5 | 2018-Jun-21 | 11.7 LD | 8.2 | 16 |
| 2018 MA | 2018-Jun-21 | 19.3 LD | 16.6 | 48 |
| 2018 LX5 | 2018-Jun-21 | 5.2 LD | 11.7 | 32 |
| 2018 LS5 | 2018-Jun-21 | 6.5 LD | 9 | 17 |
| 2017 YE5 | 2018-Jun-21 | 15.6 LD | 15.5 | 513 |
| 2018 MX6 | 2018-Jun-22 | 10 LD | 7 | 40 |
| 467309 | 2018-Jun-23 | 17.9 LD | 14 | 355 |
| 2018 MG7 | 2018-Jun-23 | 9.4 LD | 15.1 | 202 |
| 441987 | 2018-Jun-24 | 7.3 LD | 12.6 | 178 |
| 2018 LD3 | 2018-Jun-24 | 19.7 LD | 14.1 | 70 |
| 2018 MX4 | 2018-Jun-27 | 5.5 LD | 8 | 15 |
| 2018 LN2 | 2018-Jun-28 | 10.5 LD | 9.4 | 87 |
| 2018 MH7 | 2018-Jun-28 | 11.4 LD | 4.4 | 20 |
| 2018 LR3 | 2018-Jun-29 | 6 LD | 3.8 | 20 |
| 2018 LT6 | 2018-Jul-01 | 11.6 LD | 12.9 | 126 |
| 2018 LJ1 | 2018-Jul-01 | 13.9 LD | 2.7 | 18 |
| 2018 MB7 | 2018-Jul-04 | 2.8 LD | 11.6 | 63 |
Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach. | | Cosmic Rays in the Atmosphere |
Readers, thank you for your patience while we continue to develop this new section of Spaceweather.com. We've been working to streamline our data reduction, allowing us to post results from balloon flights much more rapidly, and we have developed a new data product, shown here:
This plot displays radiation measurements not only in the stratosphere, but also at aviation altitudes. Dose rates are expessed as multiples of sea level. For instance, we see that boarding a plane that flies at 25,000 feet exposes passengers to dose rates ~10x higher than sea level. At 40,000 feet, the multiplier is closer to 50x. These measurements are made by our usual cosmic ray payload as it passes through aviation altitudes en route to the stratosphere over California.
What is this all about? Approximately once a week, Spaceweather.com and the students of Earth to Sky Calculus fly space weather balloons to the stratosphere over California. These balloons are equipped with radiation sensors that detect cosmic rays, a surprisingly "down to Earth" form of space weather. Cosmic rays can seed clouds, trigger lightning, and penetrate commercial airplanes. Furthermore, there are studies ( #1, #2, #3, #4) linking cosmic rays with cardiac arrhythmias and sudden cardiac death in the general population. Our latest measurements show that cosmic rays are intensifying, with an increase of more than 13% since 2015:
Why are cosmic rays intensifying? The main reason is the sun. Solar storm clouds such as coronal mass ejections (CMEs) sweep aside cosmic rays when they pass by Earth. During Solar Maximum, CMEs are abundant and cosmic rays are held at bay. Now, however, the solar cycle is swinging toward Solar Minimum, allowing cosmic rays to return. Another reason could be the weakening of Earth's magnetic field, which helps protect us from deep-space radiation.
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.
The data points in the graph above correspond to the peak of the Reneger-Pfotzer maximum, which lies about 67,000 feet above central California. When cosmic rays crash into Earth's atmosphere, they produce a spray of secondary particles that is most intense at the entrance to the stratosphere. Physicists Eric Reneger and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today.
| | The official U.S. government space weather bureau |
| | The first place to look for information about sundogs, pillars, rainbows and related phenomena. |
| | Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever. |
| | 3D views of the sun from NASA's Solar and Terrestrial Relations Observatory |
| | Realtime and archival images of the Sun from SOHO. |
| | from the NOAA Space Environment Center |
| | fun to read, but should be taken with a grain of salt! Forecasts looking ahead more than a few days are often wrong. |
| | from the NOAA Space Environment Center |
| | the underlying science of space weather |
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