Lights Over Lapland has a brand-new website full of exciting adventures in Abisko National Park, Sweden! Take a look at our aurora activities and book your once-in-a-lifetime trip with us today! | | |
SOLAR WIND, INCOMING: A canyon-shaped hole in the sun's atmosphere is facing Earth, and it is spewing a stream of solar wind in our direction. Minor G1-class geomagnetic storms are possible when the gaseous material arrives on March 15th. Arctic sky watchers, warm up your cameras. Aurora Alerts: SMS text, email.
HAPPY PI DAY: March 14th (3.14) is day, and all around the world pi-philes are celebrating one of the most compelling and mysterious constants of Nature. Pi appears in equations describing the orbits of planets, the colors of auroras, the structure of DNA. The value of is woven into the fabric of life, the universe and ... everything.
Humans have struggled to calculate for thousands of years. Divide the circumference of a circle by its diameter; the ratio is . Sounds simple, but the devil is in the digits. While the value of is finite (a smidgen more than 3), the decimal number is infinitely long:
3.1415926535897932384626433832795
02884197169399375105820974944592307
81640628620899862803482534211706...more
Supercomputers have succeeded in calculating more than 2700 billion digits and they're still crunching. The weirdest way to compute : throw toothpicks at a table or frozen hot dogs on the floor. Party time.
NEUTRONS DETECTED ON COMMERCIAL AIRPLANE FLIGHTS: Long lines. Narrow seats. Baggage fees. You recognize this list. It's the downside of flying on modern commercial airlines. And now we have a new item to add: neutrons.
Spaceweather.com and Earth to Sky Calculus have just completed a 5-continent survey of cosmic ray neutrons at aviation altitudes. From Dec. 2018 through Feb. 2019, Hervey Allen of the University of Oregon's Network Startup Resource Center carried Earth to Sky radiation sensors including neutron bubble chambers onboard commercial flights from North America to Europe, Africa, South America and Asia. Neutrons from deep space were detected on every flight.
Hervey logged 83 hours in the air as he traveled 41,500 miles above 30,000 feet. For reference, that's almost twice the circumference of the Earth. The entire time, he gathered data on X-rays, gamma-rays and neutrons in an energy range (10 keV to 20 MeV) similar to that of medical radiology devices and "killer electrons" from the Van Allen Radiation Belts.
The results were eye-opening. During the trip, Hervey recorded 230 uGy (microGrays) of cosmic radiation. That's about the same as 23 panoramic dental x-rays or two and a half chest X-rays. Moreover, 41% of the dose came in the form of neutrons. This confirms that cosmic-ray neutrons are abundant at aviation altitudes and must be considered in any discussion of "Rads on a Plane."
Each bubble represents a cosmic ray neutron penetrating the chamber (left) on board a flight from San Francisco to South Korea and (right) crossing the Atlantic Ocean.
Researchers have long known that cosmic rays penetrate airplanes. Our own 3-year survey of global radiation shows that X-rays and gamma-rays at aviation altitudes are typically 50 times stronger than sea level. This new survey focuses on neutrons, a more potent type of radiation from deep space. Studies show that neutrons can be ten times more effective at causing biological damage compared to X-rays and gamma-rays in the same energy range. Neutrons are so effective, they are used for cancer therapy, killing tumors better than other forms of radiation.
Should we be worried about Hervey? Although he absorbed a lot of radiation during the survey, he did so slowly. Hervey's whole body dose was spread out over 14 flights and 3 months–unlike, say, a dental X-ray which is localized to the jaw and delivered in a split-second. Slow delivery gives the body time to respond, repair damage, and move on without obvious health effects. On the other hand, at least one study shows that low-dose radiation received over a long period of time may slightly increase the risk of leukaemia, while flight attendants have been found to have a higher risk of cancer than the general population.
Left: Neutrons detected while flying from Europe to Accra, Ghana. Right: Ground-level measurements in Ghana with giant ant mounds in the background.
Our survey also revealed some geographical variations. Generally speaking, neutron radiation was stronger near the Arctic Circle and weaker near the equator. It was weakest of all, however, in flights over Chile as the aircraft skirted the South Atlantic Anomaly. We will be investigating these variations with additional flights in the near future. Stay tuned!
A sharable version of this story is available here.
Realtime Aurora Photo Gallery
A MOONSTONE AT THE EDGE OF SPACE: Are you looking for a far-out gift? Nothing says "I love you" like a moonstone from the edge of space. Last month, the students of Earth to Sky Calculus flew this moonstone wrapped in a sterling silver Celtic love knot 34.1 km (111,877 feet) above Earth's surface:
You can have it for $139.95. The students are selling these pendants to support their cosmic ray ballooning program. Each one comes with a greeting card showing the item 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 sales support hands-on STEM education
Realtime Space Weather Photo Gallery
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 Mar. 14, 2019, the network reported 17 fireballs.
(17 sporadics)
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 March 14, 2019 there were 1967 potentially hazardous asteroids.
|
Recent & Upcoming Earth-asteroid encounters: Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) |
2012 DF31 | 2019-Mar-09 | 9.3 LD | 15.1 | 47 |
2019 EW1 | 2019-Mar-11 | 1.6 LD | 11.5 | 14 |
2019 CM4 | 2019-Mar-11 | 13.8 LD | 12.1 | 91 |
2019 DH | 2019-Mar-11 | 7.6 LD | 10.6 | 41 |
2019 EE1 | 2019-Mar-12 | 14.3 LD | 9.1 | 22 |
2019 DJ1 | 2019-Mar-12 | 4.1 LD | 3.8 | 16 |
2013 EG68 | 2019-Mar-13 | 19.3 LD | 17 | 37 |
2012 VZ19 | 2019-Mar-13 | 7.7 LD | 8 | 27 |
2019 EF2 | 2019-Mar-14 | 4.5 LD | 8.5 | 25 |
2019 ES | 2019-Mar-16 | 9.1 LD | 7 | 32 |
2019 DH1 | 2019-Mar-18 | 8.6 LD | 5 | 21 |
2019 CL2 | 2019-Mar-18 | 10.2 LD | 7.5 | 76 |
2019 CD5 | 2019-Mar-20 | 10.1 LD | 17 | 137 |
2019 DS | 2019-Mar-21 | 17.4 LD | 8.9 | 39 |
2019 EA2 | 2019-Mar-22 | 0.8 LD | 5.4 | 23 |
2019 EN | 2019-Mar-27 | 9.7 LD | 15.2 | 213 |
2016 GE1 | 2019-Apr-04 | 3.9 LD | 10.1 | 17 |
2014 UR | 2019-Apr-09 | 13 LD | 4.6 | 17 |
2016 GW221 | 2019-Apr-09 | 10.1 LD | 5.3 | 39 |
2012 XO134 | 2019-Apr-18 | 14.8 LD | 11 | 56 |
522684 | 2019-Apr-19 | 19 LD | 11.5 | 214 |
2018 KK1 | 2019-May-05 | 13.9 LD | 13.9 | 71 |
2017 RC | 2019-May-09 | 14.5 LD | 10.6 | 9 |
2008 HS3 | 2019-May-09 | 14.6 LD | 5.3 | 162 |
2018 VX8 | 2019-May-12 | 6.2 LD | 15.5 | 118 |
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 |
SOMETHING NEW! We have developed a new predictive model of aviation radiation. It's called E-RAD--short for Empirical RADiation model. We are constantly flying radiation sensors onboard airplanes over the US and and around the world, so far collecting more than 22,000 gps-tagged radiation measurements. Using this unique dataset, we can predict the dosage on any flight over the USA with an error no worse than 15%.
E-RAD lets us do something new: Every day we monitor approximately 1400 flights criss-crossing the 10 busiest routes in the continental USA. Typically, this includes more than 80,000 passengers per day. E-RAD calculates the radiation exposure for every single flight.
The Hot Flights Table is a daily summary of these calculations. It shows the 5 charter flights with the highest dose rates; the 5 commercial flights with the highest dose rates; 5 commercial flights with near-average dose rates; and the 5 commercial flights with the lowest dose rates. Passengers typically experience dose rates that are 20 to 70 times higher than natural radiation at sea level.
To measure radiation on airplanes, we use the same sensors we fly to the stratosphere onboard Earth to Sky Calculus cosmic ray balloons: neutron bubble chambers and X-ray/gamma-ray Geiger tubes sensitive to energies between 10 keV and 20 MeV. These energies span the range of medical X-ray machines and airport security scanners.
Column definitions: (1) The flight number; (2) The maximum dose rate during the flight, expressed in units of natural radiation at sea level; (3) The maximum altitude of the plane in feet above sea level; (4) Departure city; (5) Arrival city; (6) Duration of the flight.
SPACE WEATHER BALLOON DATA: 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 18% since 2015:
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.
En route to the stratosphere, our sensors also pass through aviation altitudes:
In this plot, 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.
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.
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 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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