Astronomy General Space Discussion

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Cosmologist are having a big pow wow to discuss the recent data undermining the conventional view the universe is uniform and the same in all directions.

www.theguardian.com

World’s top cosmologists convene to question conventional view of the universe

Meeting at London’s Royal Society will scrutinise basic model first formulated in 1922 that universe is a vast, even expanse with no notable features
www.theguardian.com www.theguardian.com

To my absolute joy, half way through the article there is this, about the appropriately named Dr Secrest of the US Naval Observatory who is -

....presenting findings that raise the possibility that the universe is slightly lopsided. After analysing a catalogue of more than 1m quasars (extremely luminous galactic cores), the team found that one hemisphere of the sky appeared to host roughly 0.5% more sources than the other.

It may not sound like a major discrepancy but, according to Sarkar, if confirmed it would undermine the basis for dark energy, which is supposed to be the dominant component of the universe. “It would mean that two-thirds of the universe has just disappeared,” Sarkar said.

I hope it means we can banish dark matter, finally. No more pixie dust.
 
www.nature.com

The importance of continents, oceans and plate tectonics for the evolution of complex life: implications for finding extraterrestrial civilizations - Scientific Reports

Within the uncertainties of involved astronomical and biological parameters, the Drake Equation typically predicts that there should be many exoplanets in our galaxy hosting active, communicative civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is...
www.nature.com www.nature.com

".....the Drake Equation typically predicts that there should be many exoplanets in our galaxy hosting active, communicative civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is often referred to as the Fermi Paradox. Here, we elaborate on this long-standing enigma by showing the importance of planetary tectonic style for biological evolution. We summarize growing evidence that a prolonged transition from Mesoproterozoic active single lid tectonics (1.6 to 1.0 Ga) to modern plate tectonics occurred in the Neoproterozoic Era (1.0 to 0.541 Ga), which dramatically accelerated emergence and evolution of complex species. We further suggest that both continents and oceans are required for ACCs because early evolution of simple life must happen in water but late evolution of advanced life capable of creating technology must happen on land. We resolve the Fermi Paradox by adding two additional terms to the Drake Equation....."
There you go, problem solved. It's a good story and most folks would agree that plate tectonics as a driver of change were vital and it was only when the early earth established various geological cycles with establishment of the plate tectonic mosaic that life started to get interesting. There's one or two other critical events in Earth's history that may be necessary for development of complex life and later on sentient beings that watch cat videos and Only Fans. That Mars sized planet that crashed into the Earth 4.5 bya may have set up some unique conditions for life. The great oxidation event 1,5 bya was a pretty big one, the big O, you can't have active animals with clever brains with out it. In the Devonian, over scores of millions of years, suffocating fish kept trying there hand (pardon the pun) at walking & breathing on land, and all but one group failing. We all owe that hardy tetrapod. The dino's had 150 million years to develop a more intelligent form capable of 'civilization', the best they managed was 'Hello Polly'. There are so many intertwining things that led to us, to pick one of them and say this is reason we have the Drake paradox is nonsense. I'm not saying plate tectonics aren't vital it's just lots of other events had to occur too.
 

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A planetary scientist who studies Enceladus discusses prospects for finding life. Some of the features of the oceans on Enceladus are similar to early earth. Bit colder, though.

'Just like Earth’s oceans, Enceladus’ ocean contains salt, most of which is sodium chloride, commonly known as table salt. The ocean also contains various carbon-based compounds, and it has a process called tidal heating that generates energy within the moon. Liquid water, carbon-based chemistry and energy are all key ingredients for life.

In 2023, I and others scientists found phosphate, another life-supporting compound, in ice grains originating from Enceladus’ ocean. Phosphate, a form of phosphorus, is vital for all life on Earth. It is part of DNA, cell membranes and bones. This was the first time that scientists detected this compound in an extraterrestrial water ocean.

Enceladus’ rocky core likely interacts with the water ocean through hydrothermal vents. These hot, geyserlike structures protrude from the ocean floor. Scientists predict that a similar setting may have been the birthplace of life on Earth.'

Part of the difficulty is going to be identifying extraterrestrial cells at a distance of 1.5+ billion km

theconversation.com

Saturn’s ocean moon Enceladus is able to support life − my research team is working out how to detect extraterrestrial cells there

Saturn’s moon Enceladus has geysers shooting tiny grains of ice into space. These grains could hold traces of life − but researchers need the right tools to tell.
theconversation.com theconversation.com
 
Japans moon lander that did a bit of a face plant, has survived it's 3rd lunar night. Just to remind folks the lunar night is 14 days long and the lander wasn't designed to last a single night clearly built with Toyota reliability. Oh what a feeling......

www.space.com

Japan's SLIM moon lander defies death to survive 3rd frigid lunar night (image)

The lander has defied all odds, given that it wasn't even designed to survive even one lunar night.
www.space.com www.space.com

Here it is visualised from orbit by the Indian orbiter, Chandrayaan-2

For the scholars - the post also has links to description of the visual recognition system used to choose the landing site on descent. Apparently worked well, the staying upright part, not so much.

Why are robotic moon landings hard? There are a couple of reasons, the first is you have to reduce the speed from 2 km/s (7200 km/hr) to something gentle enough to land over a about 10 minutes. During this time you have to pick a landing site and much of the terrain is very rough. With remote control you have a 3 s lag from the lander then a 3 s lag on your control signal getting back, plus the bit in the middle where the monkey has to make some decisions. This has led to much of the moon landing process being programmed, often with limited adaptability.

In the 20C only 2 robots successfully landed on the moon, the former Soviet Union’s Luna 9 landing and NASA's Surveyor 1 mission in 1966. In the 21st century, China, India, and Japan have successfully landed robots. The recent successful landing of the US Intuitive Machines lander was notable for being a private endeavour and the first successful US landing on the moon in over 50 years.
 
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