Mikko Tuomi

Here is a problem that has been quietly gnawing at astronomers for decades.

The standard approach to detecting #life on other worlds involves scanning #exoplanet #atmospheres for #oxygen, #methane, and #ozone, whose presence is difficult to explain without #biology.

It's a clever idea, but it carries a hidden flaw. That entire shopping list was written by studying Earth. It is, inevitably, a search for life like us.

The list of ways that #chemistry alone can accidentally mimic these #biosignature gases is growing faster than the list of new ways to detect life.

Each new false positive scenario demands even more information about the #planet to rule it out, and there is a genuine question about whether that information can ever be gathered exhaustively.

But there is a solution.

#Assembly theory doesn't ask what #molecules are present in an #atmosphere. Instead, it asks how hard they were to make.

Every molecule can be assigned an assembly index, a minimum number of construction steps required to build it from basic #chemical building blocks.

Simple molecules are easy to assemble by chance, but truly complex ones, requiring many sequential steps, don't arise without something doing a great deal of deliberate selection.

That something would then be life itself.

#astrobiology #astronomy
https://phys.org/news/2026-03-life.html

Paper by Walker et al. (2026): https://arxiv.org/abs/2603.11086

Most of Europe’s original natural #forests have been transformed for agriculture and managed forests producing energy, paper and timber.

The few remaining “old-growth” natural forests are relics of the past that illustrate how forests would have looked in the absence of human management.

Most Swedish forests are so-called #boreal forests.

This type of coniferous woodland #ecosystem encompasses most of the northern regions of the planet.

After mapping and measuring the most natural old-growth forests in Sweden, scientists found that they differ much more from managed forests than previously thought, even if some of those managed forests looked old.

Old-growth forests store 78-89% more #carbon than managed forests do, a difference in carbon storage larger than Sweden’s cumulative emissions from the combustion of fossil fuels since 1834.

These new results underscores the much larger carbon storage benefits that flow from protecting forests than using them to produce bioenergy and wood products.

#climate #nature #ecology #biological
https://theconversation.com/swedens-old-growth-natural-forests-store-83-more-carbon-than-managed-woodlands-new-study-277150

Global demand for wood products is increasing, as are calls for protecting tropical #forests from #deforestation.

In #boreal regions, where much of the #forest has not been previously logged, demand has led to clear-cutting of old, primary forest.

In a new paper, scientists assess the potential impacts of clearing primary boreal forests by comparing the carbon storage of primary and secondary (previously logged) forests in Sweden.

Including vegetation, dead wood, wood products, and soils, primary forests store over 70% more carbon than secondary forests, a difference several times greater than previous estimates.

These results reveal previously underappreciated value in protecting primary boreal forests.

#climate #ecology #biological
https://www.science.org/doi/10.1126/science.adz8554

Organic #molecules delivered from #extraterrestrial materials may have played a key role in supplying building blocks for #life on #Earth.

Now scientists report all five canonical #nucleobases—purines (#adenine and #guanine) and pyrimidines (#cytosine, #thymine and #uracil)—in samples returned from the C-type #asteroid (162173) #Ryugu.

Samples from Ryugu, #Bennu and #Orgueil, which have a similar mineralogy and elemental composition, show purine-to-pyrimidine ratios negatively correlating with #ammonia.

These observations indicate that the nucleobases in these samples may have formed via a shared pathway depending on the physicochemical environment of the respective parent bodies.

The detection of diverse nucleobases in asteroid and meteorite materials demonstrates their widespread presence throughout the Solar System and reinforces the hypothesis that carbonaceous asteroids contributed to the #prebiotic chemical inventory of early Earth.

#astronomy #astrobiology
https://www.nature.com/articles/s41550-026-02791-z

Two new studies conclude that stabilizing long-term #climate risks will require sustained net-negative carbon dioxide (CO₂) emissions for centuries.

Approaching the problem from distinct perspectives—legal and technological feasibility on the one hand, and #economic optimization under #uncertainty on the other—the research converges on a consistent message: reaching net zero is not enough.

The former study examines how to halt the growth of delayed climate impacts, such as sea-level rise and permafrost thaw, that continue to intensify even if global temperatures stabilize at 1.5°C.

Following the 2025 advisory opinion of the International Court of Justice affirming states' obligations to prevent significant climate harm, the authors assess what would be required to stop these impacts from worsening.

Their conclusion is clear: net-zero emissions alone will not stabilize these long-term damages.

The second study addresses how uncertainty in the Earth system should shape optimal climate #policy.

Widely used integrated assessment modeling approaches seldom account for uncertainty when designing optimal climate policies.

Crucially, the results indicate that sustained, potentially century-long net-negative emissions are needed, not to offset temporary overshoot, but to reduce long-term Earth system risks.

https://phys.org/news/2026-03-centuries-net-negative-emissions-required.html

Paper by Gasser et al. (2026):
https://www.nature.com/articles/s41467-026-69896-x

Paper by Bednar et al. (2026):
https://iopscience.iop.org/article/10.1088/1748-9326/ae34ca

Voidakseen ylläpitää elämää, eksoplaneettojen on kyettävä ylläpitämään magneettikenttää.

Mutta liian lähellä tähteään magneettikenttä ohjaakin tähtituulen planeetan pintaan vieden kaasukehän mennessään.

Se tuottaa ylimääräisiä rajoituksia elinkelpoisuudelle.

https://tuomim.wordpress.com/2026/03/12/eksoplaneetat-magneettikentassa/

On a cloudy day in January, historian Ivan Malara sat in Italy’s National Central Library of Florence poring over seven 16th century printings of the ancient world’s most influential astronomy text.

The pages belonged to The #Almagest, in which second century polymath Claudius #Ptolemy described his vision of an Earth-centered cosmos.

As Malara flipped through the pages, he spotted something out of place.

Someone had transcribed Psalm 145 on an otherwise blank page—in handwriting reminiscent of a very, very famous Tuscan astronomer.

That book, Malara came to realize, had been extensively annotated by none other than Galileo #Galilei.

Malara’s discovery, described in a paper now under review at the Journal for the History of Astronomy, promises new insights into one of the most famous ideological transitions in the history of science: the moment when #Earth was thrust from the center of our #universe.

#science #astronomy #history
https://www.science.org/content/article/galileo-s-handwritten-notes-found-ancient-astronomy-text

Thunderstorms often illuminate the night sky with flashes of #lightning.

They also seem to make treetops glow and sparkle—although the phenomenon is pretty much invisible to the naked eye.

Now scientists have provided the first direct observations of the weak electrical discharges around #trees in nature.

These outbursts—called coronae—are typically too faint for human eyes to detect.

But since they also emit light at #ultraviolet wavelengths, scientists were able to use a special setup involving a UV camera to document them outside of a laboratory.

#nature #science
https://www.smithsonianmag.com/smart-news/treetops-emit-ultraviolet-sparkles-during-thunderstorms-researchers-just-filmed-it-in-nature-for-the-first-time-180988275/

Although a low level of #Neanderthal ancestry is present in most #humans, the Neanderthal genes are not uniformly distributed.

A handful of regions in the #autosome are entirely devoid of such ancestry in essentially all living humans, and the X #chromosome is strongly depleted across its sequence.

These patterns are most consistent with Neanderthal contributions to human populations being heavily male biased.

The interbreeding between the two groups was predominantly that of male Neanderthals with females of the anatomically modern human population.

https://www.science.org/doi/10.1126/science.aea6774

Over the past few years, the number of #satellite launches has skyrocketed. There are now nearly 15 000 active #satellites in orbit around the Earth, most of them part of mega-constellations in which each satellite has a service life of only a few years. New satellites must be quickly launched as replacements. To avoid leaving old, dead satellites in Earth’s already-crowded low orbits, most satellite operators deliberately de-orbit them into Earth’s upper atmosphere. That approach is now being taken to a vastly larger scale and there are implications for Earth’s #climate and #atmosphere. Rocket launches already contribute to climate change and #ozone depletion. Scaling them up to deploy a million aircraft-sized satellites would push upper-atmosphere heating and ozone loss far beyond previous estimates, with the steady burn-up of dead satellites compounding the impacts. This is just a fraction of what is to come if planned mega-constellations go ahead. Operators worldwide have already asked for a combined total of over one million satellites. The very smallest particles, finer than a human hair, can stay suspended in the atmosphere for years, contributing to ozone depletion and climate change. A million satellites could mean that a teragram of alumina accumulates in the upper atmosphere – enough, alongside launch emissions, to significantly alter atmospheric chemistry and heating in dramatic ways we do not yet understand. There is no public mandate for a single company in one country to make changes on that scale to the planet’s atmosphere. #space #astronomy https://theconversation.com/a-new-space-race-could-turn-our-atmosphere-into-a-crematorium-for-satellites-276366

Astronomers have discovered a new #exoplanet orbiting a distant #star known as TIC-65910228.

A single-transit discovery, with an orbital period of 180 days, the new #planet is characterised as a super-Jupiter around a star hotter and larger than the Sun.

TIC-65910228 is a bright metal-rich star of spectral type F6V-F7V, located some 864 light years away. Estimated to be 2.2 billion years old,bit is nearly two times larger than the sun and has a mass of about 1.46 solar masses and effective temperature of 6310 K.

The planet has a radius of about 1.08 Jupiter radii and a mass of 4.78 Jupiter masses.

This is one of the longest period transiting planets ever discovered and one of only 13 planets with orbital periods of over 100 days to be discovered by #TESS.

#astronomy #exoplanets
https://phys.org/news/2026-02-astronomers-rare-super-jupiter-orbiting.html

Paper by Rodel et al. (2026): https://arxiv.org/abs/2602.12977

SpaceX filed an application with the US Federal Communications Commission for a megaconstellation of up to one million #satellites to power data centres in #space.

The proposal envisions satellites operating between 500 and 2,000 kilometres in low Earth #orbit. Some of the orbits are designed for near-constant exposure to sunlight.

The approval process for these satellites focuses almost entirely on the limited technical info companies have to submit to regulators.

Cultural, spiritual, and most #environmental impacts aren’t taken into account – but they should be.

At this scale of growth, the night #sky will change permanently and globally for generations to come.

In 2021, astronomers estimated that in less than a decade, 1 in every 15 points of light in the night sky would be a moving satellite. That estimate only included the 65 000 #megaconstellation satellites proposed at the time.

Once deployed at a scale of millions, the impacts on the night sky may not be easily reversed.

#astronomy
https://theconversation.com/too-many-satellites-earths-orbit-is-on-track-for-a-catastrophe-but-we-can-stop-it-275430

An exoplanetary system about 116 light-years from Earth could flip the script on how #planets form.

Four planets orbit LHS 1903 — a red dwarf #star, the most common type of star in the #universe — and are arranged in a peculiar sequence.

The innermost #planet is rocky, while the next two are gaseous, and then, unexpectedly, the outermost planet is also rocky.

This arrangement contradicts a pattern commonly seen across the galaxy and in our own solar system, where the rocky planets (#Mercury, #Venus, #Earth and #Mars) orbit closer to the sun and the gaseous ones (#Jupiter, #Saturn, #Uranus and #Neptune) are farther away.

Astronomers suspect this common pattern arises because planets form within a disk of gas and dust around a young star, where temperatures are much higher close to the celestial body.

In these inner regions, volatile compounds such as water and carbon dioxide are vaporized while only materials that can withstand extreme heat — such as iron and rock-forming minerals — can clump together into solid grains. The planets that form there are therefore primarily rocky.

A discovery of a planet breaking this pattern is telling about anomalies in the common formation process.

#exoplanets #astronomy
https://www.ksl.com/article/51447598/astronomers-detect-a-solar-system-they-say-should-not-be-possible

Some 700 million years ago, #Earth would have looked like a blinding white #snowball.

During the #Cryogenian period, from 720 million to 635 million years ago, the Earth was buried by massive ice sheets that marched from the poles to the tropics.

Surface temperatures were as low as -50°C.

Because the bright, white surface of the #planet reflected the Sun’s energy – a phenomenon known as the albedo effect – the Earth remained locked in this extreme climate state for tens of millions of years.

This seems an unlikely cradle for #life, yet new evidence suggests the frozen #ocean featured restricted ice-free oases that provided a lifeline for our earliest complex ancestors.

#astrobiology #planets
https://theconversation.com/snowball-earth-wasnt-fully-frozen-ice-free-oases-sheltered-early-life-275240

Entä, jos lähin tuntemamme elinkelpoisen vyöhykkeen eksoplaneetta Proxima b onkin vetinen valtameriplaneetta?

Silloin siltä voi puuttua merkittävä kaasukehä, ja se saattaa olla lähes kokonaan jääkuoren peittämä muttei kuitenkaan elinkelvoton.
https://tuomim.wordpress.com/2026/02/11/jaatynyt-valtameriplaneetta/

Stars are only point-sources of light in the sky but we can study their surface inhomogeneities anyway.

This is very obvious after considering #star #spots. They are cooler areas of the star's surface and appear darker that the surrounding surface.

Some spots are huge, others smaller, but we cannot see them on the star's surface by simply zooming in with large telescopes. The stars remain point sources, and we cannot see the stellar disk to identify areas of different temperature.

Instead, we get information because stars rotate. Co-moving on the surface, spots travel in and out of view, on the visible side of the star and behind the edge again. This can be seen by looking at the star's brightness.

Variations in brightness, around a certain period, the star's rotation period, reveal how many spots there are and what sizes and temperatures they have.

But the orientation of the star's axis of rotation is normally unknown. To overcome this, we can choose a target that has a system of transiting #planets. They ensure that the rotation axis aligns with the planetary system and its orientation is known.

But stellar surfaces are not constant in brightness. Limb-darkening makes the star appear fainter the closer the edge of stellar disk wee look at. And this effect is visible in the light-curve variations caused by spots.

We thus get the latitudes of the spot, and can construct spot maps for rotating stars.

The video shows spot evolution over about three rotation periods of the star Kepler-411. Spots come and go, producing changes into the brightness variations.

#astronomy

Paper by Tuomi et al. (2026):
https://arxiv.org/abs/2602.09224

For #life to develop on a #planet, certain chemical elements are needed in sufficient quantities.

#Phosphorus is vital for the formation of DNA and RNA, which store and transmit genetic information, and for the energy balance of cells.

#Nitrogen is an essential component of proteins, which are needed for the formation, structure, and function of cells.

Without these two elements, no life can develop out of lifeless matter but there are also more profound consequences.

During the formation of a #planet's core, there needs to be exactly the right amount of oxygen present so that phosphorus and nitrogen can remain on the surface of the planet.

This was exactly the case with Earth around 4.6 billion years ago—a stroke of chemical good fortune in the #universe.

When #planets form, they initially develop out of molten rock.

A sorting process occurs during this time: heavy metals such as iron sink down and form the core, while lighter metals form the mantle and the crust.

If there is too little #oxygen present during the formation of the core, phosphorus will fuse with heavy metals such as iron and move to the core.

This element is then no longer available for the development of life.

On the other hand, too much oxygen present during core formation leads to phosphorus remaining in the mantle and #nitrogen being more likely to escape into the #atmosphere, ultimately being lost.

#astronomy #astrobiology
https://phys.org/news/2026-02-small-planets-suitable-life.html

Paper by Walton et al. (2026):
https://www.nature.com/articles/s41550-026-02775-z

In March 2025, scientists reported identifying small amounts of decane, undecane, and dodecane in a rock sample analyzed in the chemistry lab aboard Curiosity.

These were the largest organic compounds found on #Mars, with researchers hypothesizing that they could be fragments of fatty acids preserved in the ancient mudstone in Gale Crater.

On Earth, fatty acids are produced mostly by #life, though they can be made through geologic processes, too.

Now researchers say that as the non-biological sources they considered could not fully explain the abundance of organic compounds, it is therefore reasonable to hypothesize that living things could have formed them.

To reach their conclusion, scientists combined lab radiation experiments, mathematical modeling, and Curiosity data to “rewind the clock” about 80 million years — the length of time the rock would have been exposed on the Martian surface.

This allowed them to estimate how much organic material would have been present before being destroyed by long-term exposure to cosmic radiation: far more than typical non-biological processes could produce.

#astrobiology
https://science.nasa.gov/blogs/science-news/2026/02/06/nasa-study-non-biologic-processes-dont-fully-explain-mars-organics/

Hints of non-gravitational interactions between dark matter and relic #neutrinos in the early #universe have emerged in a study of astronomical data from different periods of cosmic history.

Dark matter and neutrinos play major roles in the evolution of cosmic structures, but they are among the universe’s least-understood components.

Dark matter is thought to make up over 25% of the universe’s mass, but it has never been detected directly; instead, its existence is inferred from its gravitational interactions.

Neutrinos, for their part, are fundamental subatomic particles that have a very low mass and interact only rarely with normal matter.

According to the standard ΛCDM #model of cosmology, dark matter and neutrinos do not interact with each other.

The new results challenge this model by proposing that dark matter and neutrinos may have interacted in the past, when the universe was younger and contained many more neutrinos than it does today.

#physics #cosmology
https://physicsworld.com/a/interactions-between-dark-matter-and-neutrinos-could-resolve-a-cosmic-discrepancy/

Uusi eksoplaneettatuttavuus HD 137010 b on viileä maapallo, jonka mahdollisuudet olla elinkelpoinen ovat hyvät. Mutta todennäköisesti planeetta on pinnaltaan jäässä, jolloin elämä joutuu selviytymään pinnan alla meressä tai jäätikönalaisessa sulavedessä. https://tuomim.wordpress.com/2026/02/03/elinkelpoinen-viilea-maailma/

Scientists argue that our entry into an overshoot era—one for which existing #climate strategies were not intentionally designed—requires a fundamental rethink of accountability in climate #policy.

Exceeding 1.5°C marks our failure to prevent minimum levels of dangerous human interference with the climate system established by the UN science-policy process.

This failure should make us reflect on whether current scientific approaches are fit-for-purpose to inform overshoot policy and avoid inadvertent support for target backsliding.

Looking ahead to what we need to do to get back below 1.5°C is important, but it is equally essential to understand how we got here in the first place.

Scientific evidence is needed to clarify the foreclosed option space we could have had today with earlier, feasible, action—and who is responsible for not taking this action.

https://phys.org/news/2026-02-climate-overshoot-era-science-policy.html

Ganti et al. (2026):
https://www.nature.com/articles/d41586-026-00247-y

The mystery of dark matter—unseen, pervasive, and essential in standard #cosmology—has loomed over #physics for decades.

Rather than postulating new particles, a new study proposes that perhaps #gravity itself behaves differently on the largest scales.

Gravity might evolve when viewed through the lens of #quantum field #theory.

Instead of assuming Newton's gravitational constant is absolutely fixed at #cosmic distances, perhaps it changes with scale.

In quantum field theories, coupling constants typically depend on the energy or length scale—this is the idea of renormalization group running. While this running is well-studied at microscopic scales (high energy), it should be asked whether a similar concept might apply in reverse at immense distances.

Remarkably, such a correction leads to a long-range force, which naturally generates flat rotation curves in #galaxies, the very effect traditionally attributed to dark matter halos.

But this is only one result and many similar corrections have been proposed to explain away the dark matter of galaxies.

The key test of this new theoretical frameworkremains to be done: it must fit everything we know about gravity and predict something new that can be observationally verified.

#astronomy
https://phys.org/news/2026-02-infrared-gravity-field-theoretic-route.html

Paper by Kumar (2025):
https://www.sciencedirect.com/science/article/pii/S037026932500766X?via%3Dihub

Although #Mercury was geologically active in its early days, today its surface appears almost completely static.

This is why it is often perceived as a dead and dry #planet.

Now scientists have discovered a large number of bright streaks, also known as "lineae", on Mercury, which are presumably caused by the outgassing of volatile material from the planet's interior.

This indicates that Mercury is not a dead planet, as previously assumed, but might in fact be geologically active.

#planets
https://mediarelations.unibe.ch/media_releases/2026/media_releases_2026/streaks_mercury/index_eng.html

Over 10 000 doctoral-trained experts in science and related fields left their jobs last year as Trump regime dramatically shrank the federal workforce.

This is 14% of the total number of doctors in science, technology, engineering, and math or health fields.

#science
https://www.science.org/content/article/u-s-government-has-lost-more-10-000-stem-ph-d-s-trump-took-office

Erikoiset laavaplaneetat ovat todellisuutta.

Niilläkin voi olla kaasukehä, jos se vain kykenee uusiutumaan nopeammin kuin tähtituuli puhaltaa kaasua avaruuteen.

Seuraavana haasteena on maankaltaisten planeettojen kaasukehien tutkimus.
https://tuomim.wordpress.com/2026/01/26/katse-elinkelpoisen-planeetan-kaasukehaan/

Plate #tectonics represents a defining framework of modern #geoscience, accounting for large-scale features on Earth’s surface, such as mountains and valleys, as well as the processes that shape them, like volcanoes and earthquakes.

Present-day plate tectonics have not been observed on any other world in the solar system, and evidence of past activity on planets such as #Mars and #Venus is circumstantial.

Perhaps the best case for extraterrestrial plate tectonics is found in the floating ice shell of #Jupiter’s #moon #Europa.

The plate tectonics on Europa differs from its Earthly analog. It is spatially widespread; it is regionally confined rather than globally connected; it occurs intermittently and is not happening now; and during past activity, plates drifted limited distances of between 10 and 100 kilometers.

#planets
https://eos.org/research-spotlights/europas-plate-tectonic-activity-is-unlike-earths

Paper by Collins et al. (2022):
https://doi.org/10.1029/2022JE007492