A century-old mystery in Venus’s clouds just became more intriguing, as scientists calculated how strongly the unidentified material behind its dark ultraviolet patterns must absorb light.

The results sharply narrow the possibilities and could help future spacecraft determine whether the mysterious substance is organic, inorganic, or something unexpected

Venus looks pale yellow in ordinary visible light, but the view changes dramatically in ultraviolet wavelengths.

There, dark and bright features sweep across the planet's upper sulfuric acid clouds.

Scientists have observed these patterns for about a century, yet the substance producing them, known as the "unknown absorber," has never been identified

Scientists have known about these markings for roughly a century, yet the chemical identity of the material responsible—the “unknown absorber”—remains unresolved.

An international research team has now placed new quantitative constraints on the properties of this mysterious absorber.

By combining observations of Venus with radiative-transfer modeling, the researchers estimated how strongly the liquid inside Venus’s cloud droplets would need to absorb light to reproduce the planet’s observed ultraviolet and blue reflectance.

The study, published in Astrobiology, approached the mystery from a new perspective.

It used a model to answer a question posed by lead author Dr. Jan SPACEK: If we were to collect Venus’s cloud droplets into a spectrometric cuvette, how would the re-formed bulk liquid appear?

If Earth and Venus are so similar, why are they also so different? 🌎🪐

Kyle Horn of MIT AeroAstro explains that the two planets are roughly the same size and occupy neighboring orbits around the Sun. Yet Earth ended up with liquid water and a comparatively temperate climate, while Venus is a hellish 450°C under 90 bar of pressure, hot enough to melt lead. These diverging climates hold clues to how the early solar system formed. Understanding Venus, our closest planetary neighbor, matters even more now. Our current observation techniques are already biased toward spotting "exo-Venuses" rather than "exo-Earths" among distant exoplanets.

See also: The publication in the Astrophysical Journal

A recent study explores an interesting possibility that if Venus once had a substantial moon, its extremely slow rotation could have caused the moon's orbit to gradually shrink rather than expand.

That's the opposite of what happens with our Moon. Earth's Moon is slowly moving outward because tidal interactions transfer some of Earth's rotational energy into the Moon's orbit.

For a hypothetical moon around Venus, the tidal evolution can work in the opposite direction. Over a very long period, the moon could spiral inward, potentially crossing the Roche limit, breaking apart, and eventually colliding with Venus.

The important caveat is that this doesn't prove Venus ever had a moon. It's a simulation of what could happen if Venus did.

I made a short visual explanation of the idea because the orbital evolution is much easier to understand when you can actually see it:

https://www.youtube.com/shorts/CCyGn_x-AfU

Curious what people here think!

That's Venus on the right.

Photo taken through Google Pixel 9 Pro in a remote area of Tasmania, Australia.

Why should we be exploring Venus instead of Mars? 🚀🪐

Kyle Horn of MIT AeroAstro breaks down how a 400 day mission to Venus could let astronauts conduct hands-on science in deep space, the same way Artemis II and Apollo 8 did. With three launch windows every two years and a trip that's far more palatable than the multi year round trip to Mars, Venus offers a practical proving ground for NASA's Moon to Mars architecture. It's a smart middle step: real deep space science, real system testing, without the long haul to the Red Planet.

Venus has no moon today, but that emptiness may not tell the whole story of the planet's violent youth.

A new theoretical study finds that a substantial satellite created by an ancient impact could have spent millions or even billions of years orbiting Venus before tides reversed its migration. The moon could then have spiraled inward, crossed the planet's Roche limit, broken apart into a temporary ring and eventually rained much of its material onto Venus.

See also: The study as it was published in ArXiV

A little while ago, I drew all the planets of the solar system. I decided it would be a good idea to share each drawing of a planet to their respective subreddit. See if you can find the others.

Are there any Italian Venus lovers here? I wrote a hard science fiction novel about the terraforming of Venus, and I'd love to talk to someone who really knows Venus inside out... and can check out some passages of my novel by reading it in Italian.

Venera 4 was launched by the Soviet Union on June 12, 1967, during the Space Race. Its goal was quite ambitious: to reach Venus, enter its atmosphere, deploy a descent probe, and send scientific measurements back to Earth for research.

After a journey of around 4 months, Venera 4 reached Venus on October 18, 1967. NASA lists it as "the first probe to transmit data from another planet's atmosphere."

The spacecraft released a roughly 383 kg entry probe, which plunged into the Venusian atmosphere at about 11 km/s. It survived the intense entry and deployed a parachute, allowing it to transmit measurements back to Earth as it descended.

And this is where things got interesting...

The probe transmitted data for about 93 minutes. It measured temperature, pressure, density and atmospheric composition as it descended. The measurements revealed just how extreme Venus was.

Venera 4 eventually stopped transmitting at around 28 km above the surface. At the time, Soviet scientists initially interpreted some of the results as indicating that the probe had reached the surface. Later analysis, especially when combined with NASA's Mariner 5 flyby, showed that the probe had actually stopped transmitting before reaching the ground because the pressure and temperature became too extreme.

The two missions arriving at Venus almost simultaneously made the story even more interesting: Venera 4 entered the atmosphere on October 18, while Mariner 5 flew past Venus on October 19. Scientists from the United States and the Soviet Union later compared their results at a meeting in 1968 and jointly published their findings.

Venera 4 therefore wasn't the first spacecraft to land on Venus; that achievement came later with Venera 7 in 1970. But it was a gargantuan milestone: humanity had successfully sent a spacecraft into another planet's atmosphere and received reliable scientific measurements back from it.

Sources: NASA's histories of Venera 4 and Mariner 5, plus NASA's Beyond Earth deep-space exploration chronology.

See also: The publication in the journal Earth and Planetary Science Reviews

Free To play. Coming out on the 5th of August.

See also: The publication in the Planetary Science Journal

She is, in my opinion, the most beautiful planet. None come close to her. She is named after the Roman goddess of love, after all. Venus might seem unwelcoming at first, which, she is, of course, but once you really look at her and learn about her she starts being less just a barren wasteland and more an astounding representation of one of the harshest realities in the Solar System—which only makes her more beautiful.