Listen to radar echoes from satellites and meteors, live on listener-supported Space Weather Radio.
STRANGE SITUATION: In the middle of Solar Max, the sun has slipped into a state that resembles Solar Minimum. Sunspot numbers are low; the sun's X-ray and radio output are depressed; and NOAA forecasters estimate a scant 1% chance of solar flares during the next 24 hours. The quiet could be disturbed during the weekend, however, by the expected return of two old sunspots currently transiting the farside of the sun. Solar flare alerts: text, voice
VEINS OF HEAVEN: The luminous tendrils of noctilucent clouds (NLCs) have been likened to "frozen lightning", slow-moving bolts of electric-blue that slowly zig-zag across the twilight sky during the months of Arctic summer. Last night photographer P-M Hedén witnessed a display over Hedesunda, Sweden, that suggested a different name: "They looked like 'veins of Heaven,'" he says:
"I was really hoping for a good show like this because my children came along to watch," says Hedén. "We were not disappointed. From the beginning at 23:00 local time we saw noctilucent clouds all around the sky - amazing! Around 1 AM we had veins of Heaven both in the sky and reflected in the water."
Seeded by meteor smoke, noctilucent clouds float at the edge of space itself. They glow electric-blue when sunlight strikes them more than 80 km above Earth's surface. The fine structure that resembles lightning and evokes "heavenly veins" is not fully understood. This is just one of many mysteries about NLCs that NASA has sent its AIM spacecraft to investigate.
The natural habitat of noctilucent clouds is the Arctic Circle. In recent years, however, they have spread to lower latitudes with sightings as far south as Utah and Colorado. This may yet happen in 2014. Observing tips: Look west 30 to 60 minutes after sunset when the Sun has dipped 6o to 16o below the horizon. If you see blue-white tendrils zig-zagging across the sky, you may have spotted a noctilucent cloud.
NLC Photo Gallery
RADIO BURSTS FROM JUPITER: This week, Jupiter is passing behind the sun. Normally solar interference would make it difficult for radio astronomers to pick up Jupiter's shortwave radio bursts. Because the sun is so quiet, however, Jupiter is still able to maake itself heard. "I was able to capture distinct narrow-band radio emissions from Jupiter on July 21st," reports Thomas Ashcraft of New Mexico. They are the sloping lines in this dynamic spectrum he recorded using a RadioJove Project dual dipole antenna:
"At the time Jupiter was 6.3 Astronomical Units (585,621,586 miles) distant from Earth," he adds. "I think this is a neat observation because it means there is always the possibility of receiving Jupiter radio emissions here on Earth--even when the sun is in the way and Jupiter is very distant."
Jupiter's radio storms are caused by natural radio lasers in the planet's magnetosphere that sweep past Earth as Jupiter rotates. Electrical currents flowing between Jupiter's upper atmosphere and the volcanic moon Io can boost these emissions to power levels easily detected by ham radio antennas on Earth. Jovian "S-bursts" and "L-bursts" mimic the sounds of woodpeckers, whales, and waves crashing on the beach. Here are a few audio samples: S-bursts, S-bursts (slowed down 128:1), L-Bursts. The type of emissions Ashcraft picked up on July 21st were S-bursts.
Space Weather Photo Gallery
Aurora Photo Gallery
Comet Photo Gallery
Every night, a network
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 Jul. 24, 2014, the network reported 18 fireballs.
( 18 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
all the time.
July 25, 2014 there were 1491
potentially hazardous asteroids.
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.
official U.S. government space weather bureau
first place to look for information about sundogs,
pillars, rainbows and related phenomena.
call it a "Hubble for the sun." SDO
is the most advanced solar observatory ever.
views of the sun from NASA's Solar and Terrestrial
and archival images of the Sun from SOHO.
the NOAA Space Environment Center
underlying science of space weather