Starship Asterisk*

The main article in this weeks New Scientist is "In Search of Quantum Gravity". See: https://www.sciencedirect.com/science/article/abs/pii/S0262407923020122 if you don't have a subscription to NS. The author is a journalist, not a scientist! She describes the work of Kathryn Zurek, who pro...

A "Hunter's Moon" is it?

Thank you, Chris!
The blurb made it sound like some unknown chemistry was just pooouff! making it not exist!

The blurb to this APOD described the clouds of gas and dust as, "slowly disappearing, eroding under the influence of energetic radiation from hot and luminous gamma Cas." So where is it going? If the dust is being reduced to gas, why isn't that made luminous? Is the gas being reduced to pr...

Thank you, Ann and Chris!

So, what factor should be added to Drake's Equation, R* x FP x Ne x FL x FI x FC x L = Number of intelligent civs?
And does this answer Fermi's question, "Where is everybody?" ?

John

Great series of pics, Ann! Now, I KNOW that every star in those galaxies is light years from the next, and I KNOW that a process such as this is over a very long period, but what would it be like to live in one of colliding galaxies? "Violent tides", "bursts of star formation" it...

The habit of giving particular instants in the inevitable and unending (in human history or future)m orbit of the Moon around Earth is annoying. To me at least, while my criticism of this practice has inflamed others. So enjoy this, woo-woos!
John

Actually Randolph, the Geldingadur eruption has stopped! See: https://www.youtube.com/watch?v=uZGleOgreBY

Sure, Iceland is an extraordinary island that sits on the Mid-Atlantic Ridge, so new eruptions and revivals of dormant sites may be expected, but this one has gone silent. For now!
John

Thank you, Ann!
John

No, Ann! My question must have been unclear may I try again ? The blurb says that ARP 142 was distorted when "it got too close to the massive elliptical galaxy NGC 2937" which I presume is the one in the centre of your left pic - looks the same as in today's APoD. That galaxy appears as a ...

ARP 142 is "about 300 million LY away" the blurb says. So how close to it is the elliptical, NGC 2937?

I ask, because while the elliptical's stars are just a mist, no individuals discernible, there are many in ARP 142 that appear as single stars. Or do my eyes deceive me?
John

Why are there extra lobes of the jet in the upper-right? Intermittent jetting? If you click on the "hypothesize" link, you can read the abstract about just this. In which I love the use, in a serious astrophysics paper, of the term "wiggle"! And just to orientate us, Ann has exp...

JIm, Since we cannot detect Dark Matter in the Solar System let alone 4 billion light years away, that blue cloud must be theoretical , not observation. It's derived from conventional physics theory, and 'photoshopped' in. I read recently that the latest attempts to push definition and detection to ...

I can see four stars with diffraction spikes, so are ALL the other objects in that photo beyond the Milky Way?

If so, well, Gosh!
But another question, why do distant object not raise spikes?
Thanks,
John

Thank you, Chris! So there are many effects on the debris from a cometary outburst, that pushed them into an expanding torus along the orbit of the parent object? Which brings me to the other point in my original Q - in the APOD picture, if you draw a line between the Comet and the centre of the bun...

Indeed, emc, only the truly ignorant don't ask questions.

I know that this site will inform me.
John

Some explanation for the ignorant (me) please? The break-up may be moderately explosive, like a geyser eruption on Earth, but how do the fragments become so separated? Are they scattered along the orbit of the parent comet? Or, as all their tails are aligned, but they are all along the same line, in...

Which gorilla? Not even Uncle Boris!
Someone from Cousin Orang's family?

This appeared on Facebook.
https://www.facebook.com/reel/276761901549016 An asteroid impacts the Moon.

It has to be a simulation, looks well done, but is of course without explanation or discussion. I'd love to see those from the well-informed people here.

JOhn

Anyone seen the new Indiana Jones movie? "Dial of Destiny"? It features Indy searching for the said Dial - which is the Antikythera Mechanism!!! Except in this reality it was recovered from the sea bed "encased in wax", wholly uncorroded and - who knew? - when reunited with its' ...

The EPoD picture today provides a pleasing coincidence: https://epod.usra.edu/
John

A recent EPOD featured a 'flat rainbow', with the usual colours appearing in a plane, over Paris as it happened. But without any explanation. flat rainbow.jpg Googling this I find that they are not unique, are sometimes called 'firebows' and associated with high clouds and water ice crystals rather ...

Ann, I understand about absorbtion of colours, but am puzzled. For instance, sodium vapour street lights give off the same wavelength of light that identifies sodium in the Sun. But the sodium in the Sun must be at much higher temperature than in the street light, so why does the solar sodium not gl...

Since the stars in the constellation are in this galaxy, surely that should be, "three different massive galaxy clusters some 3.5 billion light-years away BEYOND the constellation Sculptor."?

"There are holes in the sky where the rain gets in,
but the holes are small, that's why rain is thin."

Milligan, S. "Rain"