ASTRONOMY
In the Sky this Week, Astronomy News, and TWSftUoTtCBDftSoTiFoOT
IN THE SKY THIS WEEK
Sun: The Sun has an ~11-year cycle of sunspot activity. The last minimum period was in late 2020; the next maximum has just now been reached. Peak conditions could persist for the next year, so expect more sunspots, CMEs, and auroral displays in the coming months! NOAA’s 30-Minute Aurora Forecast: https://www.swpc.noaa.gov/products/aurora-30-minute-forecast.
There are two eclipses of the Sun in 2026. The first was an annular eclipse on February 17, but visible only in Antarctica. The second solar eclipse is total, on August 12. The eclipse track passes along the east coast of Greenland, hits Reykjavik, then slashes across Spain, hitting Majorca just before local sunset. Weather conditions will be sketchy for the Atlantic Ocean part of the eclipse track, but Spain has much better good weather prospects. It’ll be a great warm-up for umbraphiles for the major solar eclipse over Egypt next year.
This reporting period is too long and too uncertain for me to provide meaningful guidance on planetary positions and satellite overpasses. You can find out more about the former in the “This Week’s Sky at a Glance” feature on the Sky & Telescope website; about comets at the aerith website; and satellite overpasses at the Heavens’ Above website.
ASTRONOMY NEWS
Light Pollution and a Crowed LEO
Successful ground-based astronomy is best conducted in areas that have a dry climate, are at a high enough altitude to be above much of the turbulent atmosphere, have a suitable human/technical infrastructure nearby for support, and are far away from light pollution. Only three areas meet all of these requirements: Mauna Kea on Hawai’i, Gran Canaria in the Canary Islands, and the Atacama Desert of Chile. Mauna Kea and Gran Canaria already have or are near having the maximum number of observatories they can accommodate. The Atacama now is home to more than half of the entire ground-based observing capability, and more is presently under construction. In Chile, the amazing Simonyi Survey Telescope at the Vera Rubin Observatory is now fully operation and returning huge quantities of data, the ALMA radio telescope array is the finest anywhere, and the Giant Magellan Telescope and Extremely Large Telescope are under construction, adding to the many fine observatories already there.
However, that “light pollution” thing is still a problem.
Astronomical research is a big deal for the economy of Chile. But so is lithium mining and the development of other natural resources, such as hydrogen for fuel. And major observatories require substantial amounts of electricity; the largest field of solar panels I have ever seen is near Paranal, one of the observatory sites. Chilean-based astronomers recently beat back an attempt by AES Chile company to build a huge hydrogen/ammonia plant less than 10 miles from Paranal. The resulting light pollution and dust generation of that plant would have crippled observations from Paranal. And hydrogen production is relatively “green;” imagine the damage from something far worse for astronomy (lithium).
Dollars versus Science is often losing proposition for Science. In this case, the plant could be cited elsewhere and Chile gets a lot of dollars from astronomy-related jobs, astronomical science, and even astronomically-related tourism (there are several tourism observatories in the Atacama). So, for now, Astronomy is ahead. But another enemy lurks above the horizon…
Satellites in Low Earth Orbit (LEO) are proliferating at a rapid rate. Constellations of thousands now crowd the skies to the point where any imaging of more than a few minutes is almost certain to have at least on satellite cross the field of view. A million more of them are being planned. And not just optical telescopes are threatened, radio signals from communications satellites are already interfering with ALMA and other ground-based radio telescopes; see also: https://www.space.com/satellite-megaconstellations-spacex-starlink-interference-astronomy . Even worse, in a filing with the FCC late Jan. 30, SpaceX proposed an orbital data center constellation of up to one million satellites in low Earth orbit. The satellites would operate at altitudes between 500 and 2,000 kilometers, in 30-degree and sun-synchronous inclinations, to maximize time in sunlight for solar power generation.
Some Space-based astronomical assets are at risk, too. The James Webb Space Telescope, stationed at L2, is far enough about LEO to be relatively immune for now (but L2 is not a large volume of space to work with and more and more satellites are planned to be placed there). However, the overcrowding of LEO, especially with a million more satellites placed there, will increase the odds of a devastating collision that would generate more debris and more collisions in a catastrophic chain reaction called the “Kessler Syndrome,” a calamity that would have devastating effects for all of us.
Lots More in the Pleiades (M45)
One of the sky’s great sights is the Pleiades star cluster, aka the “Seven Sisters,” in western mythology, the daughters Atlas, a Titan, and Pleione, an Oceanid nymph who gave the seven their collective name. The sisters were companions of Artemis, Apollo’s sister, and the nursemaids for Dionysus. Six of them “married” well: Maia, who bore Hermes by Zeus; Electra, Zeus again; Alcyone, Poseidon; Taygete, Poseidon again; Celaeno, Poseidon yet again; and Sterope, Ares. Merope was the only sister to marry a mortal, the boulder-rolling Sisyphus, and hides her shame in a cloud of nebulosity as a consequence. The modern cluster has the entire family, and then some, and its appearance in the morning sky portended the start of the sailing season in the Mediterranean.
Sharp-eyed folks in a favorable location can see even more, and with modern backyard scopes now available, just about anyone can image the cluster and see dozens of stars in a nest of nebulosity. Such clusters are known to be groups of stars that form at the same time from the same batch of material.
Recently, a team of astronomers based out of the University of North Carolina have used data from Gaia and TESS to find hundreds of other Pleiades “siblings” scattered across the sky, many quite far from the original boundaries of the Pleiades cluster. “The findings have broad implications. The Pleiades is not only an astrophysical benchmark for young stars and exoplanets but also a cultural touchstone featured worldwide in the Old Testament and Talmud, celebrated as Matariki in New Zealand, and even represented by the logo of Subaru in Japan.”
Finding such a broad distribution of sibling stars provides clues as to how solar systems form and evolve. For more information, see: https://phys.org/news/2025-11-pleiades-star-cluster-revealed-vast.html and https://www.sciencedaily.com/releases/2025/11/251116105945.htm.
ASTRONOMY FYI
Farewell Sunspot Solar Telescope
The specialized needs of astronomers means that some ground-based telescopes have to be of specialized construction, and not usable for other astronomical observations. A case in point is the telescopes used to study the Sun, an object so bright that gathering light is not particularly useful (however, size is needed to ensure adequate image resolution!). Famous solar telescopes include the McMath-Pierce Solar Telescope at Kitt Peak, the Goode Solar Telescope at Big Bear Lake, and the 150-foot Tower at Mt. Wilson; there are dozens of others.
One of the most interesting designs for a solar telescope was created by Richard Dunn, who worked at the Sacramento Peak Observatory in New Mexico. Intense heating of the optics used in a solar telescope posed a serious engineering problem, solved in this case by enclosing the telescope in a 300’ partially-buried tower, with the whole thing encased in a vacuum chamber. There was no need for a protective dome, the sunlight came through a window at the top of the tower, guided into the vertically-pointing telescope chamber by a tracking mirror. The telescope itself did not have a conventional mirror, rather, the main “optical element” was a 40-ton vat of mercury. The meniscus of the top of the vat focused the sunlight into the various measuring devices used. The telescope was completed in 1969 and has been in useful service until now.
Alas, all good things must come to an end, and the Dunn Solar Telescope (nee the Sunspot Solar Telescope) is being decommissioned. The mercury vat sprang a leak, and the NSF determined that repairing the telescope would not be cost-effective, especially with the remediation required to render the site safe again. For more about the Dunn telescope and its fate, see: https://en.wikipedia.org/wiki/Richard_B._Dunn_Solar_Telescope#History and https://www.kob.com/new-mexico-/sunspot-solar-observatory-to-be-permanently-closed-demolished
Cosmic Dawn: NASA prepared a YouTube video about the “Untold Story of the James Webb Space Telescope.” It covers the building, testing, launch, and operation of the best Space telescope ever built. The JWST, and the video, are most impressive! See it at: https://www.nasa.gov/cosmicdawn!
Nearby Supernova: Astronomers at the University of Warwick have found a compact binary star system only ~150 light-years away that will likely produce a powerful Type 1s super-nova explosion. But not to worry, the event lies some 23 billion years in the future. The two stars in the system are larger white dwarf stars, orbiting one another separated by only a few million miles. That’s close enough for mass to be ripped from one and passed to the other, a process that will eventually cause the two to merge. Most Type 1a supernovae are formed by collisions between two white dwarfs or a white dwarf and a neutron star. If the Earth is still 150 light-years away when that collision happens, the resulting supernova will be on the order of ten times brighter than the full Moon. For more on this discovery, see: https://www.sciencedaily.com/releases/2025/04/250404122624.htm.
Supernovae Were Bad News for Paleozoic Life: Geologists use abrupt changes in fossil assemblages to denote boundaries of geologic time periods. Perhaps the best known is the Chicxulub impact event that “killed off the dinosaurs,” marking the end of the Mesozoic Era. But not all mass extinction events are due to asteroid impacts. Recent research conducted at Keele University suggest that nearby supernovae explosions were responsible for mass extinction events in the Paleozoic Era. The earliest came in the Ordovician Period, 445 million years ago, and was marked by the extinction of 60% of the marine invertebrates alive at that time (there were few land-dwellers that long ago). The second came in the late Devonian Period, 372 million years ago, which wiped out 70% of all species then living, and made abrupt changes in marine animals of that time. The mass extinctions had been known about for some time, but there was no meteoritic material in deposits of that time, like there was at Chicxulub. The timing and frequency of supernova events in the Milky Way is consistent with the timing of the extinction events, which would have been capable of depleting Earth’s ozone layer in the upper atmosphere, allowing killing radiation to play havoc with the species living at that time. For more info on this story, see: https://www.sciencedaily.com/releases/2025/04/250404122624.htm.
Supernovae, Impacts, and Humans: The two previous stories are built around mass extinctions in the geologic record. Five major ones are known, including the three mentioned above. There is strong evidence that we are presently living in the sixth, this time caused by human activity. Research evidence indicates that 7.5 - 13% of the species present in 1500 CE have become extinct, most due to habitat loss and climate change induced by human activity. 500+ years is a long time by human standards, but a mere eyeblink in terms of geologic time, so the observed reduction in species could be construed as a “mass extinction” event. Read more about this issue while you still can at: https://www.sciencedaily.com/releases/2022/01/220113194911.htm.
Black Holes: Beginnings?! When the expansion of the Universe became general consensus, several aspects of it were troubling from a philosophical point of view. Questions like: “What happened before the Big Bang?” and “What happens in the future when matter is spread out to the extreme?” were the subject of speculation. One idea was the Steady-State Hypothesis, which held that matter was being continuously created to maintain the Universe’s overall density. But that required an almost magical creation of something from nothing. Another was the “Oscillating Theory,” which held that the present observed expansion would be eventually countered by gravity, causing the expansion to cease, then contraction until all matter was concentrated in one mass, aka the “Big Crunch.” Rinse and repeat, the cycles of creation/destruction have existed and will always exist. But the observed rate of expansion is presently increasing, not decreasing….
How’s this for a teaser to a news article?
“New research suggests black holes may transition into 'white holes', ejecting matter and potentially even time back into the universe, defying our current understanding of these cosmic giants. The study by the University of Sheffield proposes a revolutionary link between time and dark energy, suggesting that the mysterious force driving the universe's expansion may be used to measure time.”
Find out more about this astonishing idea here: https://www.sciencedaily.com/releases/2025/03/250312124602.htm.
Without Infrastructure, Little is Possible: A truism in many contexts, including astronomy. For example, images from the James Webb Space Telescope dazzle professional astronomers and the public alike. The really-complex-yet-extremely-successful satellite is a marvel of engineering design and construction (as only NASA can!). But JWST would be of no value without the supporting infrastructure here on Earth that receives the information from its instruments.
Downlinks of data are always of paramount importance, but communicating with satellites in LEO or Geosynchronous orbit is simple compared with receiving data from JWST, which orbits the Sun-Earth L2 point, a million miles away. NASA’s Deep Space Network, originally built 60 years ago to ensure continuous radio contact with early manned spacecraft, is still up to the task! Although I’d bet that the electronics of their receivers and transmitters may have had an upgrade or two over the decades!
The DSN is an engineering marvel. For a summary, see here; for the DSN website, see here; and if you want to see whose signal the DSN is receiving, see here.
TWSftUoTtCBDftSoTiFoOT
The World Society for the Understanding of Things that Can Be Understood from the Study of Things in Front of Other Things says: An astonishing amount of Science can be conducted via the Study of Things in Front of Other Things! Examples range from the confirmation of Relativity by observations made during a total solar eclipse to asteroid shapes to rings around Uranus to planets of other Suns. Since many exoplanets have been discovered when they were “in front of other things,” all exoplanet and SETI news and info will be covered in the section below.
An Exoplanet with a Warmer Star and a Longer Orbital Period than Most has been discovered by citizen scientists. Find out more about it in the Citizen Science section!
Panspermia is the notion that the early Earth was “seeded” with life from extraterrestrial sources. It’s actually an old idea, gaining traction somewhat because of discoveries of organic molecules in interstellar Space. The March, 2026, issue of Sky and Telescope has an interesting article on it, “Lord Kelvin and Space Seeds.”
Pandora is the latest satellite tool for the study of exoplanets. Launched on January 11, it is capable of observing stellar systems in visible and IR for extended periods, observing minute changes in the starlight being partially blocked by the exoplanet that can yield information about its atmosphere. Pandora’s primary instrument is a very sensitive detector of the near-infrared part of the spectrum. It was the back-up for the identical detector aboard the JWST. Not only will it be able to ascertain the compositions of known exoplanets, its data will help calibrate the data from the same instrument on JWST, which can see much farther in both Space and time. The linked-to page also gives access to material about Pandora from NASA’s Scientific Visualization Studio. For more information, see: https://science.nasa.gov/centers-and-facilities/goddard/nasas-pandora-mission-one-step-closer-to-probing-alien-atmospheres; https://phys.org/news/2026-01-nasa-pandora-telescope-stars-exoplanets.html and https://science.nasa.gov/universe/exoplanets/nasas-pandora-satellite-cubesats-to-explore-exoplanets-beyond.
Exoplanet K2-18b: There was a recent splash in the media recently about astronomers possibly detecting conditions indicative of biological activity on exoplanet K2-18b, a “mere” 120 light-years or so away. What’s up with that?
Astronomers have found thousands of exoplanets that pass between us and their stars, causing a small but detectable drop in brightness. The technique and equipment have advanced to the point where they can now determine the composition of the atmosphere of some exoplanets. When they pass in front of their star, specific gases absorb specific wavelengths of light and re-emit them in all directions. From our perspective, those exact wavelengths are “missing,” a form of chemical “fingerprints.” Sounds wild, but that’s how astronomers discovered the element helium and how they can measure the composition of stars (see also here).
K2-18b was found by the transit method, and when the JWST was used to observe the transits in detail astronomers found the spectral signature of two gases, dimethyl sulfide and dimethyl disulfide. On Earth, those two compounds are quite rare, and the only known we that they are produced in nature is as a byproduct of the metabolism of biological organisms. In addition, we know that K2-18b lies in its star’s “Goldilocks Zone,” meaning its surface temperature is likely in the range where water is liquid at least part of its orbit. It is nine times more massive than the Earth, but oddly less dense, meaning much of its mass is unusually light for a planet. One possibility of the cause of its low density is that it has a large component of something, like water, that is lighter than rock. Are those chemicals biological in origin? Big Question!
For a reasonable analysis of this issue, see: https://news.stanford.edu/stories/2025/04/four-questions-laura-schaefer-alien-life-k2-18b; the original announcement from the University of Cambridge is here: https://www.cam.ac.uk/stories/strongest-hints-of-biological-activity.
UPDATE (5/28): Additional analysis of the spectral data indicates that chemicals other than dimethyl sulfide and dimethyl disulfide could possibly explain the results, which would undercut the “potential biology signal” conclusion. Such is the nature of science; for more information on this story, see: https://phys.org/news/2025-05-alien-life-dim-emerge-exoplanet.html.
A Primer in Transits: NASA posted an introductory piece to the TWSFTUOTTCBDFTSOTIFOOT favorite of planetary transits here. Detecting the small drop in light from a star when its exoplanet transits across its face is one of the primary means of detecting exoplanets, enabled by ground-based observation and satellites like Kepler and TESS. While the transit method has produced many exoplanet findings, but other methods are useful, too (see immediately below).
Constraints on Extraterrestrial Life? The transit method used to detect almost all known exoplanets (e.g. using TESS, Kepler) works very well, but suffers from a huge selection effect. Large planets orbiting very close to their stars are readily detected, but a planetary system like our own would be almost impossible to detect that way. After all, how often do we see Mercury or Venus in transit of our own Sun? For a transit of the Sun to be seen at interstellar distances, the observer would have to be very close to the Plane of the Ecliptic. Therefore, most exoplanets detected to date orbit red dwarfs very closely. Life on them could be adversely impacted by the extreme space weather associated with many red dwarfs.
A new study using data from NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton satellite were used to assess the environment in which known exoplanets such as Wolf 359 orbit. Wolf 359 was a good test subject. It is suspected of having two exoplanets, and it is only 7.8 light-years away. Chandra and XMM-Newton can make more detailed measurements of it than they can from more distant exoplanet systems. The assessment of X-ray and Extreme UV radiation suggest that for life to exist in such a system, it would have to be on an exoplanet that has a dense atmosphere and be fairly far away from its star. The “Goldilocks Zone” from Wolf 359 was determined to be about 15 million miles and fairly narrow, between the likely orbits of the two as-yet-confirmed exoplanets. And if the regular X-ray environment made prospects for life iffy, Wolf 369 also spews very powerful and destructive X-ray flares on a frequent basis.
For more information about this research, see: https://www.nasa.gov/general/exoplanets-need-to-be-prepared-for-extreme-space-weather-chandra-finds.
SEARCH FOR HABITABLE EXOPLANETS
Habitable Worlds Observatory: Yes, Virginia, there will be such a thing in the future. The 2020 Astronomy Decadal Survey strongly recommended that NASA “develop a 6-meter Space telescope capable of high-contrast observations in optical, infra-red, and ultraviolet wavelengths.” Its primary mission will be to examine 25 different exoplanets in detail, all in their star’s “Goldilocks Zone,” searching for biosignatures. Knowing which stars to choose is obviously of great importance. That work is presently underway; NASA’s Exoplanet Exploration Program has developed a list of 164 candidates to date, based on five selection criteria: stellar composition, photometric values, flare rate, variability, and potentially-sterilizing X-ray emissions. For more information on this project, see: https://phys.org/news/2024-01-astronomers-habitable-worlds-observatory.html and https://science.nasa.gov/astrophysics/programs/habitable-worlds-observatory.
SEARCH FOR INTELLIGENT LIFE ELSEWHERE
Part 1: UCLA’s Jean-Luc Margot is the founder of UCLA SETI’s “Are We Alone in the Universe?” project. Their mission is to detect “technosignatures by searching individual systems. Dr. Margot teaches a graduate course in SETI, and he had his students use TESS data for the closer known exoplanets to narrow the search for such emissions in great detail. No provable technosignatures were seen. Even though the smally sample observed didn’t show emissions, the skills developed by the students (e.g. signal processing, telecommunications, and statistics and other data analysis tools) will no doubt improve their academic success.
Part 2: Traditional SETI tactics, like Dr. Margot’s project, is one way to search. The Breakthrough Listen program (which uses citizen scientists) takes a different approach. Rather than look at relatively-close systems, they are using the Green Bank (West Virginia) and Parkes Murriyang radio telescopes to look for very high powered technosignatures, an entire galaxy at a time. For more on this program and strategy, see: https://phys.org/news/2023-12-breakthrough-scans-entire-galaxies-extremely.html.
Part 3: NASA has produced a six-part on-line series on how it is searching for life in the cosmos. If you are interested in the real science behind this topic, then check out these episodes while they are still available! Part 1: Beginnings: Life on Our World and Others; Part 2: Life on Other Planets: What is Life and What Does It Need?; Part 3: The Hunt for Life on Mars – and Elsewhere in the Solar System; Part 4: “Life” in the Lab; Part 5: Searching for Signs of Intelligent Life: Technosignatures (see also this week’s Gravity Assist entry in the Solar System section); and Part 6: Finding Life Beyond Earth: What Comes Next?
What Happens After We Discover Life Elsewhere? Mary Voytek, Director of NASA’s Astrobiology Program, has some interesting thoughts on the subject. Check them out at: https://exoplanets.nasa.gov/news/1766/finding-life-beyond-earth-what-comes-next!
Exoplanet Travel Bureau is NASA’s source for whimsical travel posters showcasing various exoplanets as tourist destinations and other exoplanet information. See: https://exoplanets.nasa.gov/alien-worlds/exoplanet-travel-bureau!
ASTRONOMY LINKS AND OTHER INFORMATION
Astronomy.com: https://astronomy.com/news
Phys.org: https://phys.org/space-news/astronomy
Space.com: https://www.space.com/news
Science Daily: https://www.sciencedaily.com/news/space_time/astronomy
Sky and Telescope: https://skyandtelescope.org/astronomy-news
NASA Exoplanet Exploration News: https://exoplanets.nasa.gov/news