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akasci.bsky.social
AkaSci
@akasci.bsky.social
660 followers 780 following 180 posts
SatCom Scientist
Writing occasionally about science, space missions, astronomy, planetary science, satellites, Democracy and human rights.
Mostly at https://fosstodon.org/@AkaSci
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akasci.bsky.social
Lots of good #aurora sightings tonight in North America and Europe.

Caused by Coronal Mass Ejections (CMEs) on Nov 9 and 10.

A stronger X.1 solar flare occurred today at 1004 UTC from solar region 4274, which should arrive Wednesday around 19:00 UTC.

Search aurora for pics.
www.swpc.noaa.gov
1. Graphic from animation showing the path and extent of 3 CMEs headed toward earth. 2. Image of the Sun with the Nov 11 solar flare eruption 3. Graphics from NOAA SWPC showing space weather conditions over the past 2 days and forecast for the next 3 days.
November 12, 2025 at 5:03 AM
akasci.bsky.social
Happy World Jellyfish Day!
🪼🪼
Jellyfish are invertebrates, not fish.
Jellyfish go back over 500 million years.
There are over 2,000 known species of jellyfish.
One species of jellyfish possesses a property like no other animal - immortality!
...
Much more at fosstodon.org/@AkaSci/1154...
#Science
Pic of the Black sea nettle, Chrysaora achlyos Source: Monterey Bay Aquarium https://www.montereybayaquarium.org/animals/animals-a-to-z/jellies This giant jelly has a distinctive purplish bell and long, lacy mouth-arms that can reach 20 feet (6 m). Its tentacles can extend even longer, reaching 25 feet (7.6 m) or more.
November 3, 2025 at 11:40 PM
akasci.bsky.social
OTD on Oct 29, 1969, ARPANET was born, which led to the development of today's Internet.

At 10:30 pm PST, SRI programmer Bill Duvall and UCLA student programmer Charley Kline made the first successful host-to-host login connection.
👏
en.wikipedia.org/wiki/ARPANET
#History
1. Handrawn diagram of the 4 node ARPENT in Nov 1969, with some added annotations by me 2. First ARPANET IMP log message. This IMP Log excerpt, kept at UCLA, describes setting up a message transmission from the UCLA SDS Sigma 7 Host computer to the SRI SDS 940 Host computer. 3. Photo of the front panel of the very first Interface Message Processor (IMP). This was used at the UCLA site. https://en.wikipedia.org/wiki/Interface_Message_Processor 4. Pic of plaque at SRI from IEEE - "Inception of the ARPANET, 1969 SRI was one of the first two nodes, with the University of California at Los Angeles, on the ARPANET, the first digital global network based on packet switching and demand access. The first documented ARPANET connection was from UCLA to SRI on 29 October 1969 at 10:30 p.m. The ARPANET’s technology and deployment laid the foundation for the development of the Internet." This milestone's plaque can be seen in the Visitors Lobby of SRI International Building A, 333 Ravenswood Ave., Menlo Park, CA 94025 (GPS: 37.45758, -122.17642), which is open to the public 7am-6pm on weekdays. It is the 1st of 3 Milestone plaques mounted on the left wall. The dedication of this Milestone took place at the Computer History Museum in Mountain View, CA on September 16, 2009, with Internet Pioneer Vint Cerf amongst those officiating. Source: https://ethw.org/Milestones:Inception_of_the_ARPANET,_1969
October 29, 2025 at 2:38 PM
akasci.bsky.social
The horror of the night sky being destroyed by Starlink (and other LEO) satellites.

Still from time-lapse video of comet C/2025 A6 (Lemmon) by Michael Jäger and Gerald Rhemann.

Video at spaceweathergallery2.com/indiv_upload...
Cleaned up images at skyweek.wordpress.com/2025/10/
#Astronomy #Comet
Still from a time-lapse video of comet C/2025 A6 (Lemmon) by Michael Jäger and Gerald Rhemann. Shows the long wispy tail of the comet. The long exposure is marred by LEO satellites criss-crossing the image.
October 28, 2025 at 2:20 PM
akasci.bsky.social
One more outstanding and artistic shot of Comet C/2025 A6 (Lemmon) by astro-photographer Marina Prol from the Canary Islands, taken on October 25.
☄️
www.marinaprol.com/astroandnigh...
Credit: Marina Prol
#Astronomy
Comet C/2025 A6 (Lemmon) seen from high elevation with an orange backlit cloud layer below it, dark and starry skies above it and a golden glowing sea at the bottom. Commentary by Marina Pol on X: Comet C/2025 A6 (Lemmon), Gran Canaria and Tenerife. We went up to avoid the low clouds and there were also high ones. We took advantage of the windows we had and enjoyed the views and the good transparency, despite the pesky clouds.
October 27, 2025 at 10:40 PM
akasci.bsky.social
An eerie starry view from the eye of Hurricane #Melissa taken last night by meteorologist Matthew Cappucci onboard a NOAA Hurricane Hunter aircraft. The Lockheed P-3 Orion (tail N42RF) took off from Lakeland Linder Intl Airport east of Tampa.
🌀
Credit: Matthew Cappucci and Alina Cooper
1. Pic taken from the eye of Hurricane Melissa at night. The eyewall is dark, the top of the wall is grey, stars can be seen in the sky above https://x.com/MyRadarWX/status/1982699961461748196 https://x.com/MatthewCappucci/status/1982700357366030538 2. Pic of hurricane hunter aircraft taking off from the airport https://x.com/juststormchasin/status/1982578135590928392 Matthew Cappucci wrote: THE EYE OF MELISSA: On the entirety of planet Earth, there's no place else experiencing the type of indescribable weird, eeriness that's found within the eye of a high-end hurricane. It's poetically sinister; destruction juxtaposed with peace. A timeless "time out" of sorts where, for just a moment, everything is calm and quaint – though, on all sides, you're surrounded by imminent devastation. It's like an alternate reality that only lasts a few moments. I capture this photo overnight Sunday night into Monday as Melissa approached Category 4 strength. I was onboard the NOAA Hurricane Hunters aircraft as it sampled data in the core of Hurricane Melissa south of Jamaica. In this photo, you can see it all – clear, start-studded skies overhead, reminiscent of a warm summer's night. But, curving around me, you see the eyewall – a 140-150 buzzsaw of mayhem, madness and destruction. That eyewall contains hell on Earth, and yet I was in a 12 mile-wide safe haven. The eyewall is the innermost ring of extreme winds that surrounds a hurricane's center. Picture the center of a sink drain; fluid is spiraling inward. Warm, moist air rushes toward the middle, sapping heat energy from the ocean below. It screams inwards and upwards, forming a ring of thunderstorms 50,000 feet high. Winds in the eyewall reach ridiculous speeds; over the open ocean, wind over 150 mph will be possible by Tuesday. ...
October 27, 2025 at 12:05 PM
akasci.bsky.social
The 90,000 sq ft floor space is very likely across 2 (or more) levels.
The floor below the ballroom will have guest suites, conf rooms and who knows what else.
A 2nd floor will be added to the East Colonnade.
1. Satellite image of White House, outline of new ballroom building and approx dimensions of various structures 2. Side view drawing of proposed ballroom building
October 27, 2025 at 3:00 AM
akasci.bsky.social
Yet another spectacular image of Comet C/2025 A6 (Lemmon) over Suotojärvi Lake, northern Sweden, taken by Petr Horálek on October 24, with the sky lit up by the dazzling red and green Aurora Borealis.
☄️😮
www.petrhoralek.com?p=25820
#Astronomy
Commentary by Petr Horále - Last night was incredible. I have just moved to Sweden, where I organize astrophotography workshop for a group, and this is the view of nature offered over Suotojärvi Lake. The comet C/2025 A6 Lemmon was seemingly swimming in bright Aurora Borealis. The comet was so bright that we could see it with our naked eyes, even very low over the horizon. Captured after 20:30 UTC, Used Nikon Z6III, Nikkor 135mm, f1.8, ISO 3200, 4s exposure foreground, 15x4s comet from tripod (stacked).
October 26, 2025 at 6:15 PM
akasci.bsky.social
Another fabulous shot of Comet C/2025 A6 (Lemmon) over Suotojärvi Lake, Sweden, by Petr Horálek, with the colorful Aurora Borealis lighting up the sky.

More at www.petrhoralek.com?p=25820 and
fosstodon.org/@AkaSci/1154...
#Astronomy
Commentary by Petr Horále - Last night was incredible. I have just moved to Sweden, where I organize astrophotography workshop for a group, and this is the view of nature offered over Suotojärvi Lake. The comet C/2025 A6 Lemmon was seemingly swimming in bright Aurora Borealis. The comet was so bright that we could see it with our naked eyes, even very low over the horizon. Captured after 20:30 UTC, Used Nikon Z6III, Nikkor 135mm, f1.8, ISO 3200, 4s exposure foreground, 15x4s comet from tripod (stacked).
October 26, 2025 at 1:23 PM
akasci.bsky.social
Overnight, Hurricane #Melissa, now sporting a distinct eye, grew from Cat 1 (90 mph wind speeds) to Cat 4 (140 mph).

Landfall in Jamaica - Tuesday morning.

Catastrophic amounts of rain, 40+ inches in some areas in Jamaica, storm surges, life-threatening flooding and landslides.
www.nhc.noaa.gov
1. Satellite image of Hurricane Melissa and surrounding area this morning with a sharp eye 2. Graph of Hurricane Melissa wind speeds - past actual values and future predictions.
October 26, 2025 at 10:41 AM
akasci.bsky.social
Elongation is the angle between the observer-sun line and the observer-comet line.
Observations cannot be made if the angle is too small due to interference from the Sun.
The minimum angle supported varies by telescope.
Elongation does not sound like an intuitive name for this feature.
Illustration of elongation angle between a telescope, the Sun and the Comet.
October 25, 2025 at 11:41 AM
akasci.bsky.social
Many spacecraft will get a chance to observe Interstellar comet 3I/ATLAS.

ESA Juice will collect imaging and spectral data from ~0.4 AU distance.

NASA Europa Clipper can potentially sample the plasma and dust tail from ~1 AU away.

fosstodon.org/@AkaSci/1153...
arxiv.org/pdf/2508.15768
#Astronomy
1. Table from paper of various spacecraft (and earth) and observation parameters during their closest approach of the comet. 2. Map of the solar system and locations of 3I/ATLAS, the inner planets and various spacecraft on Nov 4, with some added annotations by me https://eyes.nasa.gov/apps/solar-system/#/c_2025_n1?rate=0&time=2025-11-04T16:17:20.000+00:00 
October 25, 2025 at 6:57 AM
akasci.bsky.social
The horror, the horror!

www.tysto.com/ew1.htm
#Politics #UsPol #WhiteHouse #EastWing
Pics of the East Wing - 1. Map of the first floor of the East Wing. Click on the sections of the map on the website to see more photographs. 2. Pergola and garden in 2006 (Lafayette) 3. Obama and dog running in the East Colonnade, 2008 4. Holiday season pic of East Colonnade in 2008 5. Lobby of the East Wing in 2014, looking west 6. Artists impression of the horrific giant Ballroom that will replace the East Wing and its garden.
October 24, 2025 at 12:43 PM
akasci.bsky.social
Yet another outstanding image of Comet C/2025 A6 (Lemmon) by Petr Horálek taken on October 18, from the shore of Seč Lake, Czech Republic.

The pic also captures the aurora caused by a G2 geomagnetic storm that day and the storm's effect on the comet's long ion tail.
☄️
www.petrhoralek.com
#Astronomy
Pic of the comet with the lake in the foreground and a crimson aurora lighting up the skyline. Instagram post by Petr: SOLAR WIND IN COMET'S TAIL AND EARTH'S SKY: Yesterday evening, a truly unusual view was possible to capture from Seč Lake, Czech Republic. CME from the Sun hit the Earth, producing a G2 geomagnetic storm, including faint auroras even in mid-latitudes. As the comet C/2025 A6 Lemmon approaches Earth (in 2 days), the same cloud from the sun affected even the complicated ion tail of the comet. I succeeded with deeper imaging to reveal that moment in the tail as well as the aurora itself. It doesn't happen every day to capture the invisible solar wind in two sky phenomena at the same moment! Camera: Canon Ra, Sigma Art 50mm, f 1.4, ISO 4000, 43x8s.
October 22, 2025 at 11:45 AM
akasci.bsky.social
Outstanding shot of Comet C/2025 A6 (Lemmon) with fine and sharp details of its wispy tail imaged by astro-photographers Michael Jäger and Gerald Rhemann on October 13.
☄️
How many galaxies can you spot in the starry background?

Equipment: LRGB 8/1/1/1 min 11" RASA QHY 600
#Astronomy
Telescopic shot of comet posted on X by Michael Jäger @Komet123Jager C/2025 A6 Lemmon 2025-10-13 17.45 UT LRGB 8/1/1/1 min 11" RASA QHY 600 Michael Jäger, Gerald Rhemann Besides stars, a few elliptical galaxies are visible in the background https://x.com/Komet123Jager/status/1978214780562211215
October 18, 2025 at 3:16 AM
akasci.bsky.social
Comet C/2025 A6 (Lemmon) over Mt Shasta, California, beautifully captured by photographer Kenneth LeRose last night.
☄️
Kenneth LeRose's website - www.krlphoto.com/shop-art
More on the comet at fosstodon.org/@AkaSci/1153...
#Astronomy
Image of the comet posted on X by KRL @KennethLerose "You saw the cell phone shot on my last post and here’s the one from my camera for Comet C/2025 Lemmon last night with Mt Shasta. ☄️"
October 17, 2025 at 11:22 PM
akasci.bsky.social
An intriguing hi-res photograph of the NASA-ISRO Synthetic Aperture Radar (NISAR) satellite with its 12m antenna fully unfurled in space. The pic was taken on Aug 21 by one of the earth observation satellites in the Vantor (formerly Maxar) Constellation.
www.linkedin.com/feed/update/...
#PlanetSci
1. The NISAR image taken by one of the WorldView Legion satellites 2. Same image with vector info showing orientation of NISAR relative to its imaging targets. Source: Vantor
October 17, 2025 at 11:48 AM
akasci.bsky.social
Comet C/2025 A6 (Lemmon) beautifully captured by astro-photographer Petr Horálek on October 9, from the shore of Seč Lake, Czech Republic.

Check out his other works at www.petrhoralek.com

Quiz: Was this photo taken before sunrise or after sunset?
#Astronomy
1/n
Comet C/2025 A6 Lemmon in the distance beyond a lake and low tree-lined hills. The Big Dipper looms above it. Description by photographer Petr Horálek: After many cloudy nights, I was finally lucky again to shoot the brightening comet C/2025 A6 Lemmon, which is currently well found south of the Big Dipper asterism. I took the chance from the shore of Seč Lake, Czech Republic, just shortly before a fog completely covered the lake valley. Despite the strong moonlight, the tail of the comet seems to be significant and most likely will show even nicer structures when dark evenings come again.
October 12, 2025 at 5:40 PM
akasci.bsky.social
ESA today inaugurated a new 35-m deep space antenna at its New Norcia site, ~115 km north of Perth, Australia – the 4th of its kind for Estrack, ESA’s deep space tracking network.

www.esa.int/Enabling_Sup...
More at fosstodon.org/@AkaSci/1153...
#Astronomy
Pic from the inauguration ceremony of team leaders and guests with the antenna in the background. The effort was led by ESA Director General Josef Aschbacher alongside Enrico Palermo, Head of the Australian Space Agency, and Rolf Densing, ESA Director of Operations, together with Stephen Dawson, the Western Australia Minister for Regional Development, Ports, Science and Innovation, Medical Research and the Kimberley, with Sabine Winton, Western Australia Minister for Education, Early Childhood, Preventative Health and the Wheatbelt, in attendance. Credit: ESA
October 4, 2025 at 5:02 PM
akasci.bsky.social
Mungo crater on asteroid Donaldjohanson is named after Lake Mungo, site of the oldest human fossils in Australia dated circa 42,000 BCE.

The lake is the traditional land of the Paakantji, Ngylampaa and Mutthi Mutthi peoples.

More at fosstodon.org/@AkaSci/1152...
medium.com/teatime-hist...
#Science
1. Map of SE Australia with location of Lake Mungo https://www.google.com/maps/place/Lake+Mungo/@-36.094131,142.9952767,7.07z/data=!4m6!3m5!1s0x6ae7f27f13b520ef:0x3f38c9ad66983ef2!8m2!3d-33.7233742!4d143.0566409!16zL20vMDdfeXkx!5m1!1e4?entry=ttu&g_ep=EgoyMDI1MDkxNC4wIKXMDSoASAFQAw%3D%3D 2. Pic of erosion mounds and sand drift, Lake Mungo. Credit: Simon Cameron https://medium.com/teatime-history/australia-on-the-ground-42000-bce-lake-mungo-6fa817f64615 Check out Simon's writings at the above website. 3. Skeleton remains of Mungo Man dated to 40,000 years ago
September 17, 2025 at 11:26 PM
akasci.bsky.social
Asteroid Donaldjohanson just got some new names for its various surface features.

The names were proposed by the NASA Lucy mission team to the IAU based on various paleoanthropological sites and discoveries.

science.nasa.gov/solar-system...
#PlanetSci
Pic of asteroid Donaldjohanson with annotations for recognized names of its geologic features. Few annotations added by me. Names include: Afar Lobus (Lobe) Olduvai Lobus (Lobe) Windover Collum (Neck) Hadar Regio (Region) Minatogawa Regio (Region) Narmada (Crater) Mingo (Crater) Luzia Dorsum (Ridge) Cashel Saxum (Boulder) Kennewicks Saxum (Boulder) Boxgrove Saxum (Boulder) Credit: NASA Goddard/SwRI/Johns Hopkins APL
September 16, 2025 at 11:46 PM
akasci.bsky.social
Where is star cluster PISMIS-24, the subject of the stunning new image by the JWST, located?

The following images show the location of PISMIS-24, zooming in from a view of the night sky into the central core of the Lobster Nebula (NGC 6357).
🤩
More at fosstodon.org/@AkaSci/1151...
#Astronomy
Images show the location of PISMIS-24, zooming in from a view of the night sky into the central core of the Lobster Nebula (NGC 6357). Sources: https://stellarium-web.org/ https://www.eso.org/public/images/eso1226c/ https://noirlab.edu/public/images/noirlab2221a/ https://chandra.harvard.edu/photo/2016/ngc6357/ https://webbtelescope.org/contents/media/images/2025/136/01K2JB2E4SSMC8Y7BGYE8N96TM
September 6, 2025 at 11:10 AM
akasci.bsky.social
Direct imaging of exoplanets is possible using ground based telescopes thanks to adaptive optics, coronagraphs, polarization filters (light reflected off planets and dust is polarized), IR bands translucent to earth's atmosphere, large antennas and spectroscopy.
#Astronomy #PlanetSci
2/n
1. Schematic of an Adaptive Optics system. A deformable mirror (DM) in the optical path is used to correct for distortions caused by atmosphere turbulence. Source: https://www.sciencedirect.com/topics/earth-and-planetary-sciences/adaptive-optics 2. Schematic of a Microlens Array Focusing a Distorted Wavefront A Shack-Hartmann waveform sensor uses small lenses to create images of a reference star. The displacements of these images from the ideal positions is used to calculate corrections for the DM, over 1,000 times a second. Source: https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=5287 3. The center of the Milky Way as seen from Keck, with and without adaptive optics, showing how much clearer the view becomes with AO on. Image from the UCLA Galactic Center Group. Source: https://astrobites.org/2022/11/20/guide-to-adaptive-optics/
September 1, 2025 at 12:21 AM
akasci.bsky.social
Did the DOJ lawyers make this argument (straight from the White House) to justify their actions?
Let's hope the judge sees these tweets anyways.
August 31, 2025 at 10:46 PM
akasci.bsky.social
Stunning images of a multi-ringed disk around the star WISPIT 2 and its embedded planet WISPIT 2b taken using the SPHERE extreme adaptive optics imager at the ESO Very Large Telescope (VLT) in Chile.
More at fosstodon.org/@AkaSci/1151...
#Astronomy #PlanetSci
1. SPHERE/IRDIS multiband RGB image of the WISPIT 2 system. The H-band Qϕ image was added as the blue channel and the median combination of the H-band and Ks-band Qϕ images was added as the green channel. The red channel is a combination of the Ks-band Qϕ image and the Ks-band cADI image in which we masked all but the gap containing the thermal emission from WISPIT 2b. Uses combination of polarized and unpolarized light. 1 AU = Mean Sun-Earth distance = ~150 million km Source: https://iopscience.iop.org/article/10.3847/2041-8213/adf721 2. K-band RDI image (total intensity) image with a radius distance scaling from the central star applied to compensate for the drop-off in stellar illumination of the disk. For illustrative purposes the inset on the right panel shows an image of Jupiter. The authors think that WISPIT 2b looks similar to this. Source: https://www.christian-ginski.com/home/northeast-rgt98
August 31, 2025 at 10:30 PM