Following up yesterdays post here is a pair of static images from Hubble. Click the image for a larger view.
These composite images show a suspected plume of material erupting two years apart from the same location on Jupiter’s icy moon Europa. The images bolster evidence that the plumes are a real phenomenon, flaring up intermittently in the same region on the satellite. Both plumes, photographed in ultraviolet light by NASA’s Hubble’s Space Telescope Imaging Spectrograph, were seen in silhouette as the moon passed in front of Jupiter.
The newly imaged plume, shown at right, rises about 62 miles (100 kilometers) above Europa’s frozen surface. The image was taken Feb. 22, 2016. The plume in the image at left, observed by Hubble on March 17, 2014, originates from the same location. It is estimated to be about 30 miles (50 kilometers) high. The snapshot of Europa, superimposed on the Hubble image, was assembled from data from NASA’s Galileo mission to Jupiter.
The plumes correspond to the location of an unusually warm spot on the moon’s icy crust, seen in the late 1990s by the Galileo spacecraft (see PIA21444 use back button to return.). Researchers speculate that this might be circumstantial evidence for water venting from the moon’s subsurface. The material could be associated with the global ocean that is believed to be present beneath the frozen crust.
Image Credit: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center
Spring is in the air and it just arrived in the Northern Hemisphere! Yes, at 10:29 UTC / 06:29 EDT the Sun crossed the equator. In reality the Sun’s rays fall directly on the equator in the journey north – see below (Thanks to timeanddate.com).
Naturally this means the Southern Hemisphere is heading into autumn and hopefully will slow down the tropical systems that have been going on.
Let me tell you Spring will be very welcome here after our recent snow storm of more than 76 cm / 30 inches. Thankfully it was a very dry snow and settled quickly.
Many people believe that the December solstice marks the point were the Earth’s orbit takes it closest to the sun. It turns out the tilt of the Earth (and what determines day length) and where it is in orbit do not quite coincide.
Today at 14:18 UTC the Earth reaches perihelion, the closest we get to the Sun in our orbit.
An almost spotless Sun and you just know 15 and 20 meter HF propagation is going down the tubes again. Here’s hoping the bottom of the solar cycle does not last as long as the last time.
The peak of the solar cycle wasn’t much to write home about either, just my opinion. Oh sure we had our good periods but all in all not so good. Funny too because the “forecasts” were for the peak to be HUGE with off the chart solar storm etc. Didn’t happen. I know I watch closely being an Amateur Radio operator (one who LOVES 15 meter QRP CW).
The original caption released with this SDO image:
This week the sun was hitting its lowest level of solar activity since 2011 (Nov. 14-18, 2016) as it gradually marches toward solar minimum. This activity is usually measured by sunspot count and over the past several days the sun has been almost spotless. The sun has a pendulum-like pattern of solar cycle of activity that extends over about an 11-year period. The last peak of activity was in early 2014. At this point in time, the sunspot numbers seem to be sliding downwards faster than expected, though the solar minimum level should not occur until 2021. No doubt more and larger sunspots will inevitably appear, but we’ll just have to wait and see.
NASA’s Kepler and Swift missions have allowed astronomers to discover a group of rapidly spinning stars that produce X-rays at more than 100 times the peak levels ever seen from the sun. These stars spin so fast the equatorial region to bulges out and the polar regions to flatten, making them look more or less like a pumpkin. Hey it’s Halloween and scientists are typically a good natured lot.
Soyuz Commander Sergey Ryzhikov and Flight Engineer Andrey Borisenko of Roscosmos and Flight Engineer Shane Kimbrough of NASA along with their backups, Alexander Misurkin and Nikolai Tikhonov of Roscosmos and Flight Engineer Mark Vande Hei of NASA are the group comprising the crew of ISS Expedition 49-50.
The group are actively preparing for launch at the Soyuz MS-02 to the International Space Station on 19 October from the Baikonur Cosmodrome.
It looks like Kennedy Space Center is right in the path of Matthew. Good luck!
Update from Kennedy Space Center at 19:17 UTC 15:17 EDT: The wind conditions at Kennedy Space Center have dropped below 40 knots and preliminary damage assessments are under way. KSC is now in a “Weather Safe” condition as of 2 p.m. Friday. While there is damage to numerous facilities at KSC, it consists largely roof damage, window damage, water intrusion, damage to modular buildings and to building siding. There does not appear to be damage to flight hardware at this time. The Damage Assessment and Recovery team will undertake more detailed inspection on Saturday and will enter all facilities. The Kennedy Space Center Visitor Complex will be closed on Saturday and will reopen on Sunday. Based on the damage assessment, the return to work status for KSC employees will be determined Saturday afternoon.
The September equinox arrives/arrived at 14:21 UTC. or 10:21 EDT. Autumn in the north and spring in the south.
The image here came from timeanddate.com and is a good depiction of what is going on: Today at 14:21 UTC the equator of the Earth is pointed right at the center of the sun. As the Earth travels in its orbit the position of the Sun with respect to the equator changes. In September the tilt is such that the center of the Sun is moving south. By late December the Earth has moved sufficiently in orbit the apparent movement stops (the December solstice) and starts going back north.