Andrew Fraknoi
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fraknoi.bsky.social
Andrew Fraknoi
@fraknoi.bsky.social
890 followers 150 following 140 posts
Semi-retired astronomer, college professor, lead author of a free, open-source textbook (OpenStax Astronomy), and science fiction writer with 8 stories published so far. See fraknoi.com
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fraknoi.bsky.social
Sat night, the #astrosociety of the Pacific gave the 2025 Fraknoi Award for extraordinary support of the Society's educational work to Connie Walker of #NOIRLab For more on her work see: bit.ly/2025fraknoia...
#astronomy #astroedu @conniewalker.bsky.social #lightpollution #scienceawards
The 2025 Andrew Fraknoi Award for Outstanding Support of the Astronomical Society of the Pacific and its work on science education goes to Dr. Connie Walker of the National Optical Astronomy Observatories (now known as NOIRLab)
November 10, 2025 at 7:35 PM
fraknoi.bsky.social
Teaching a fun, illustrated Zoom course on atomic science for poets (meaning everyone.) Tuesdays Oct & Nov through the SF State OLLI program. For details & how to register: bit.ly/atomscourse
#science #physics #atomic #scienceeducation #astroedu #onlinecourses #Zoomcourses #sciencefiction #quantum
The course on atomic science is for everyone. It will use historical anecdotes, analogies from everyday life, thought experiments, and touches of humor.
September 20, 2025 at 5:30 PM
fraknoi.bsky.social
This wonderful cartoon was sent out today in an email from The New Yorker magazine. All teachers will especially appreciate this.
#cartoons #teaching #astroedu #education #teachers #politicalcartoons #humor
In the cartoon, the man says, "I can't believe that summer, and civilization, are almost over."
August 19, 2025 at 8:17 PM
fraknoi.bsky.social
My latest astronomical #sciencefiction story (my 11th) was recently published. It's a new twist on doomsday & advanced #extraterrestrials - "In Conversation with the Downloaded Me." It's at: bit.ly/downloadedme
A list of all my published stories: bit.ly/sfbyfraknoi
#astroedu #hardsf #space #scifi
This graphic showing a rocket reads "science fiction." I am an astronomer writing scientifically reasonable science fiction stories, with eleven published so far.
August 11, 2025 at 4:54 PM
fraknoi.bsky.social
This uncanny image shows LDN43, the cosmic bat nebula -- a region of dark dust & dense gas, where new stars are forming. The nebula is 1400 lightyears away and about 12 lightyears across. #astronomy #astroedu #astrophotos #space #spacephotos #spaceimages #astrophotography #nebula #spacepictures
The dark nebula with catalog number LDN43 resembles a flying bat. It is a cloud of dense gas and dust inside which new stars are forming, accounting for the lighter regions that paint the features of the bat. Image credit: Mark Hanson and Mike Selby.
July 22, 2025 at 8:53 PM
fraknoi.bsky.social
Beautiful image from Gemini Observatory: the dome of their telescope on Maunkea peak, Hawaii. In this time exposure, see the stars circle the north pole of the sky as our planet rotates. Laser beams that probe atmospheric distortion add interest. #astronomy #astroedu #astrophotos #spacephotos #sky
This long time-exposure of the Gemini North Telescope dome on the 14,000 foot peak of Maunakea in Hawaii show the stars making circular trails around the north pole of the sky and the Pole Star Polaris. Some of the guide-star laser beams that help astronomers keep track of dancing of the Earth's atmosphere are also seen coming from the dome.
July 16, 2025 at 12:41 AM
fraknoi.bsky.social
Friday will be the #summersolstice -- the longest day and shortest night for the Northern Hemisphere. For the full story of how an ancient cosmic accident is responsible for our seasons, see: www.fraknoi.com/seasons/frid...
#astronomy #astroedu #space #science #seasons #sky #solstice
June 17, 2025 at 5:09 PM
fraknoi.bsky.social
Amazing star-forming region, the Tarantula #Nebula, 160,000 lightyears away & 600 lightyears wide. Another great composite image produced by noted amateur astronomer #RobGendler. Massive, luminous baby stars help it to glow.
#astronomy #astroedu #space #spacephotos #astroimaging #sciencephotos
The Tarantula Nebula: a composite image produced by Rob Gendler from data provided by the European Southern Observatory and the Hubble Space Telescope. It is a star-forming nebula -- a region of gas and dust, lit up by the light of newly-born stars inside.
June 4, 2025 at 10:26 PM
fraknoi.bsky.social
This coming weekend the summer meeting of the American Astronomical Society #AAS starts. If the administration's budget is passed by Congress, the science of #astronomy will be decimated in the U.S.
#astroedu #sciencefunding #UFOs #extraterrestrials #cartoons #sciencecartoons #astronomycartoons
Cartoon from an old New Yorker magazine shows two aliens in a flying saucer. One says to the other: "I hope my address to the American Astronomical Society will bring us the credibility we've been seeking." The American Astronomical Society is the professional organization of astronomer in the U.S.
June 2, 2025 at 5:14 PM
fraknoi.bsky.social
My latest #sciencefiction story "The Lurker" is just out in "The Worlds Within" online magazine: theworldswithin.net/the-lurker/ Just as we send probes to other planets, might advanced aliens not send AI probes to our system? Please check it out.
#astronomy #astroedu #SETI #scifi #extraterrestrials
This is the illustration for my science-fiction story the Lurker. It’s about the possibility that advanced civilizations among the stars might send automated probes to our solar system (and others); probes that wait - lurking quietly – to detect some sign of intelligent life. I tried to imagine how some hapless explorers in the future might accidentally trigger one of these probes.
May 24, 2025 at 6:06 PM
fraknoi.bsky.social
My latest (short) science-fiction story "Eclipsed" was published today. It's about how rare total eclipses might be, not just in the solar system, but the universe. See: bit.ly/eclipsedsfst...
#astronomy #astroedu #scifi #sciencefiction #hardsf #hardsciencefiction #eclipses #eclipsechasing
Eclipse sequence, showing how a total eclipse of the Sun happens, by Rick Fienberg (astronomer, astro-photographer, and veteran eclipse chaser.) Here the Moon exactly covers the Sun, blotting out its entire body, and allowing its faint atmosphere to become visible.
May 20, 2025 at 2:08 AM
fraknoi.bsky.social
For those who enjoy #StarTrek and fine art, this is a T-shirt you can buy. (I am not involved with the company, just amused.)

#astronomy #astroedu #sciencefiction #art #scifi #VanGogh #sciencehumor #astroart #scienceandart
May 15, 2025 at 6:05 PM
fraknoi.bsky.social
We see the Veil Nebula, a small part of a vast ancient remnant of an exploded star, still glowing with colorful emissions from hydrogen, oxygen, and sulfur atoms.
#astronomy #astroedu #astrophotography #space #spaceimages #spacephotos #astroimages #NASA #sciencephotos
This colorful region of glowing gas, often called the Veil Nebula, is part of the large, old supernova remnant called the Cygnus Loop. A massive star exploded some 10-20 thousand years ago and the remnant is still glowing in places. Astronomers have determined that oxygen, sulfur, and hydrogen atoms are contributing to the glow.
May 13, 2025 at 11:14 PM
fraknoi.bsky.social
Today is the birthday (in 1900) of Cecilia Payne, the astronomer who wrote what some historians call the most important PhD thesis in astronomy -- showing that stars were made mostly of hydrogen and helium.
#astronomy #astroedu #astronomyhistory #historyofscience #womenastronomers #womeninscience
Cecilia Payne, born in England, got her PhD in the U.S., showing the then controversial result that the vast majority of each star is composed of the simplest elements hydrogen and helium. This contradicted the widely held notion that the Sun and the Earth should have roughly the same composition. As a woman, she was not allowed to hold a professorship at Harvard for many year during her long career there.
May 10, 2025 at 6:23 PM
fraknoi.bsky.social
Beautiful image by Robert Fesen & collaborators showing a Wolf-Rayet star (WR8) -- a massive star violently letting go its outer layer (blue) against a background of glowing gas.
#astronomy #astroedu #astrophotography #space #spacephotography #astroimages #sciencephotos #spacephotos #astrophotos
WR8, a Wolf-Rayet Star. These are massive stars losing their outer layers forcefully toward the end of their lives. The blue is the ejected material, the reddish glow comes from glowing gas and dust lying behind or front of the star, but not connected with it.
May 2, 2025 at 5:23 PM
fraknoi.bsky.social
Complex, beautiful image, assembled by Rob Gendler, from several visible-light & Infrared telescopes, shows the Ring Nebula, with its many shells of material emitted by a dying star.
#astronomy #astroedu #space #spacephotos #astroimaging #stars #sciencephotos #astrophotography #spaceimages
The Ring Nebula, a "planetary" nebula (misnomer), probably better called a death-shroud nebula. This material, shown in a photo that combines visible-light and infrared images, is emitted in several steps from a dying star, in the process of becoming a dense white dwarf. The hot star excites that material that "lifted off" and makes it glow.
May 1, 2025 at 12:21 AM
fraknoi.bsky.social
Beautiful new #HubbleTelescope image of the "death-shroud nebula" with catalog designation #NGC2899. The central star is giving off its outer layers in dying. What does the cavity in the gas look like to you?
#astronomy #astroedu #space #spacephotos #astroimaging #astronomyphotos #sciencephotos
Planetary nebula NGC 2899 glows from the energy of the hot white dwarf star in the center. The cavity in the expelled gas resembles the shape of a moth. The shape may be the result of the fact that the dying star that gave rise to the nebula orbits around a companion star in the center. The whole nebula is more than 2 lightyears across.
April 24, 2025 at 7:42 PM
fraknoi.bsky.social
Sign in a bookstore window, appropriate for the day after Earth Day. (Now that I am a published science-fiction writer, I pay special attention to such signs.)
#climatechange #science #sciencehumor #apocalypse #globalwarming #sciencefiction #bookstores
Sign in the window of a book store indicating that stories about what it's like after the apocalypse have been moved to "current affairs."
April 23, 2025 at 7:59 PM
fraknoi.bsky.social
Tonight and tomorrow night are peak times to see the #Lyrids #meteorshower -- a time when more shooting stars are visible if you go to a dark, open site and are patient. The chart shows you the main showers of 2025 and rates them.
#astronomy #astroedu #sky #amateurastronomy #darksky #space #meteors
Listing of the meteor showers of 2025. ZHR tell you how many meteors you might see under IDEAL conditions. The star ratings are based on whether moonlight is likely to interfere with your viewing faint meteors.
April 21, 2025 at 6:57 PM
fraknoi.bsky.social
Beautiful composite image by #RobertGendler of galaxy M83, 12 million lightyears away. The red regions are nebulae, where gas clouds are glowing with the energy of recently-formed baby stars within them.
#astronomy #astroedu #space #spacehotos #astroimages #spacephotography #astrophotos #galaxies
The spiral galaxy M83 highlighting red regions of glowing gas and dust, where new stars and planets are forming. It's been called the galaxy of a thousand rubies. Image composed by Robert Gendler from Hubble and other telescope data.
April 20, 2025 at 8:06 PM
fraknoi.bsky.social
Beautiful new infrared image of "star-death" nebula NGC1514 with the #JamesWebb telescope. The dying star in the center is actually a pair of stars that orbit each other in 9 years; the #nebula is hourglass shaped. #astronomy #astroedu #NASA #JWST #space #spacephotography #astroimages #spaceimages
April 14, 2025 at 8:11 PM
fraknoi.bsky.social
128 new moons have recently been identified around Saturn, bringing its total number of moons to a record-breaking 274. Some of the new moons orbit Saturn backward, indicating they're captured and not original.
#astronomy #astroedu #planetaryscience #NASA #space #Saturn #spacephotos #spacenews
Saturn casts a shadow on its magnificent ring system in this image taken from NASA's Cassini orbiter in 2016.
April 7, 2025 at 4:48 PM
fraknoi.bsky.social
Nonprofit #OpenStax announced that the free, online book #Astronomy has now been used by 1.3 million students at 2100 colleges, saving them $92 million in textbook costs. Anyone can read it at: bit.ly/astronomytex...
#astroedu #textbooks #freeontheweb #sciencebooks #opensource #openeducation
The free online textbook Astronomy, written by Andrew Fraknoi, David Morrison, and Sidney Wolff, is now the most frequently used intro astronomy textbook in North America.
April 3, 2025 at 6:10 PM
fraknoi.bsky.social
Apr. 9 UC Professor #JonathanFortney will give a free, public, nontechnical talk on latest #JamesWebbTelescope results on #exoplanet atmospheres. #FoothillCollege in Los Altos, CA, 7 pm in Smithwick Theater. If you can't go, it will be on the Silicon Valley Astronomy Lectures #YouTube channel later.
Artist's conception of a planet orbiting a star with catalog name WASP 80, in whose atmosphere astronomers have discovered the presence of the molecule methane. On Earth, much of our methane is produced by the action of living things.
March 30, 2025 at 5:26 PM
fraknoi.bsky.social
#Hubble telescope image: NGC3350, a spiral galaxy, 40 million lightyears away. The bright central star is actually in our own Milky Way, just 10,000 LY away. It's a chance superposition.
#astronomy #astroedu #space #spacephotography #scienceimages #spacephotos #astrophotography #HST #astronomyimages
Spiral Galaxy NGC 5330, with clear spiral arms. It seems to have a bright star near its center, but that star is actually in our own Milky Way, much closer to us. It's a chance alignment.
March 28, 2025 at 9:59 PM