Astronomy General Space Discussion

[CD Xbow]

New Scientist have a nice review article on 'the problems with cosmology' and the lambda-CDM (cosmic constant-Cold Dark Matter) model of the Universe. It looks at the results from a telescopes designed to probe dark energy, the Dark Energy Spectroscopic Instrument (DESI)

https://archive.is/Lr3pv#selection-955.76-955.86

"When DESI researchers combined this with the latest data from supernovae – which tightly constrain the expansion of the nearby universe – and the CMB (Cosmic Microwave Background radiation), then checked how well it all fits with lambda-CDM, they found that the current model doesn’t match up, at least not as well as one that allows the strength of dark energy to change over time. The headline finding was stark: dark energy appears to be weakening, and isn’t a cosmological constant after all.
“It was actually quite frightening,” says Will Percival, an astrophysicist at the University of Waterloo in Canada who is part of the DESI collaboration. Of course, there was a high level of scrutiny, he says. “But in many ways, this is exactly what people have been waiting for. Experiments that take us into the unknown and give us unusual, unexpected results are incredibly exciting.”

And as if that wasn’t enough, the DESI results also suggest that in the early universe, dark energy may have dipped below the so-called phantom divide – the threshold below which its repulsive power would have been far stronger than the cosmological constant allows – before swinging back up again."

 

[footballsack35]

whats the best telescope to buy for a beginner. buget $300 - $600

 

[bommer16]

whats the best telescope to buy for a beginner. buget $300 - $600

Depends on what they want to see with it. A scope that can view planets and the moon at a good magnification might not be great for viewing the wider sky and vice versa. No scope really does it all. Will this setup be stationary or need to be portable?
There are scope setups for certain astronomy and astrophotography needs.

If they are an absolute beginner to astronomy and have never used a scope, a very good pair of wide (10 x 50) binoculars in that price range would be great and very portable. They can be handheld without too much shake. Binoculars with more magnification than 10x will need a tripod. Again depends on what they want to see -closer or wider.

A scope is a very cool gift idea but my best advice is chat to those who sell this gear and suggest the better setups for your budget as there is a bit to consider.

 

[CD Xbow]

whats the best telescope to buy for a beginner. buget $300 - $600

I have a old Meade ETX 90 with a star finder, I used it twice! It worked great!
I think it's a pretty decent 3.5" scope

Meade ETX-90 AT Telescope Review (Now Discontinued)

Meade’s flagship beginner telescope, the ETX-90’s latest incarnation offers plenty of features but commands an extraordinarily high price.

telescopicwatch.com

Actually if you want it, make me an offer!
I'll have to get it out of the attic and check out it works.

 

[CD Xbow]

A very hopeful finding of all 5 nucleotides used in RNA and DNA are present in the samples returned from asteroid Ryugu. All of uracil as well as adenine, guanine, cytosine and thymine.

https://phys.org/news/2026-03-ryugu-asteroid-samples-dna-rna.html

I think the galaxy is going to be full of water based life, most of it very simple, not grey dudes with wrap around eyes. We will get a better idea when we explore the solar system further. Scientists suggest a number of environments could harbour life, the subsurface oceans (Europa, Enceladus, Ganymede, possibly Callisto and Ceres), ancient or transient liquid water on Mars, Titan’s organic‑rich surface and even the clouds of Venus, in the sweet spot for temperature and pressure. So there are a few places to look.

A reminder of how fundamental these nucleotides are:


This one is also interesting.

Planets not orbiting any star are called rogue planets, free-floating planets, or interstellar planets. The article below looks at the possibility of liquid water on moons orbiting such planets being kept warm by geothermal heating. I do have a quibble about the use of the word habitable, I really don't consider a hydrogen atmosphere habitable. It would have been more accurate to use the word warm.

Hydrogen atmospheres could keep exomoons habitable for billions of years

Study finds moons orbiting starless rogue planets could sustain liquid oceans for 4.3 billion years using tidal heating

www.thebrighterside.news

 

[CD Xbow]

One hundred years since Goddard launched the first liquid fuelled rocket, perhaps even more amazing is it took only half that time to scale up the engines big enough to launch a Saturn V an reach the moon.

The first modern rocket launched 100 years ago, beginning a century of both innovations and challenges for spaceflight

From World War II to the Apollo era, the space shuttle program and today’s privately developed commercial rockets, the landscape of spaceflight has changed dramatically.

theconversation.com

 

[CD Xbow]

Scientist may have detected a massive black hole collision and it may have produced a Gamma ray burst (GRB). I think this is the first time a GRB has been associated with a collision.

https://phys.org/news/2026-03-solar-mass-black-hole-merger.html

'Black hole collisions were thought to be "dark" to conventional telescopes, emitting no light. The 2024 event S241125n, however, appears to defy that notion. About 11 seconds after the gravitational-wave signal, NASA's Swift observatory detected a short GRB in the same patch of sky, and shortly thereafter, China's new Einstein Probe satellite found an X-ray afterglow in that vicinity.'
'One striking aspect of S241125n is its extreme distance. The gravitational waves traveled for roughly 4.2 billion light-years to reach Earth (redshift z ≈ 0.73), meaning this collision occurred when the universe was significantly younger. The black holes involved were unusually massive.

Analysis suggests the merging pair had a combined mass well over 100 times the solar mass, making them among the heftiest stellar-mass black hole mergers recorded'

 

[CD Xbow]

This article describes an 'agnostic' way of looking for the presence of life, not just our our water based form. I'm all for ending H20 chauvinisms when it comes to looking for life.

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

As the article says:

'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 system is called assembly theory and it basically looks a complexity and the interconnectedness of the molecular signatures found. The quote below includes a link to an article that talks about it in great detail

'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.'

 

[GreyCrow]

don't arise without something doing a great deal of deliberate selection.'

My concern with this line is its an out for God botherers

I await the day we find Earth-like life on other planets - even little green/grey men - or anything above bacterial level

As it will invalidate the opening chapter of the Bible

 

[CD Xbow]

My concern with this line is its an out for God botherers

I await the day we find Earth-like life on other planets - even little green/grey men - or anything above bacterial level

As it will invalidate the opening chapter of the Bible

I don't need proof of alien life to know the story of genesis is a yarn by late stone age folks. I do like the bit "let there be light" because it parallels the big bang.

Artemis II is getting ready for launch, the first link is to a general article about the mission, the second discusses the heat shield problems and after reading it I'm glad I am not an astronaut. I'll have my fingers crossed and happily sacrifice a goat or two for good luck. Artemis II is going to sweep around the moon and take the astronauts the furtherest away from Earth that humans have ever been.

NASA set for first crewed moon return in over half a century - The Korea Times

CAPE CANAVERAL, Florida — NASA is preparing to launch the first crew of astronauts toward the moon in over 53 years with its second Artemis mission...

www.koreatimes.co.kr

Heat shield safety concerns raise stakes for Nasa’s Artemis II Moon mission

Worries were raised when the heat shield from a previous mission came back damaged.

theconversation.com

 

[Rotayjay]

I, for one, am really looking forward to seeing pictures of the whole Earth taken with modern cameras. This hasn't been done since 1972. I know there are a few such photos out there taken by satellites, but they will be better taken by astronauts.

Imagine lying there in your seat, strapped in, and thinking, 'I'm going to the moon.' Fantastic.

 

[Kram]

Less than an hour to go.

 

[CD Xbow]

This UK group have demonstrated the beginnings of a direct fusion drive in the lab, the sort of thing needed for travel around the solar system. Be a great breakthrough if they getting working as advertised. It's early days, here is a link talking about their 'first plasma'.

“First Plasma” Achieved in the Race for a Propulsion System that Could Cut the Travel Time to Mars in Half

“First plasma” has been achieved by the Sunbird exhaust test system, marking a major step toward a direct fusion drive spacecraft.

thedebrief.org

Here is the glossy YouTube video