Jump to content

More space news!


tkdguy

Recommended Posts

I cannot now recall where I heard this, but someone pushed numbers around and it seems that radiolysis of water (breaking water apart, generally into protons and hydoxyl ions, usually by gamma rays or X-rays, but other radiation can cause this to occur as well) and other substances at depth in the Earth can produce the sort of chemical disequilibrium that chemosynthetic bacteria would employ both as an energy source and as source for needed nutrients.  Protons and sulfate ions are the two big ones in the discussion I remember; we know of archaeans that get by on just those ions in terms of energy source. 

 

Radiolysis will go on in within Earth for a long, long time, with thorium-232 having a half-life of 14 Gyr.  The amount of water in the mantle isn't something I was able to find estimates for, but there is some.  Whether or not you could get life started in the deep interior is unknown, but once it invades that part (survivors of organisms that rode the subducted oceanic plates down) it could be there for keeps.  You won't make metazoans that way, but the idea that every planet might have a deep biosphere of at least this sort is worth thinking about.

Link to comment
Share on other sites

Astrophysical Journal Letters paper on two detected black hole-neutron star merger events

 

... and the two events were only ten days apart.  Probably unreadable for most people, but this is the paper all other articles about this stuff are drawing from.  Open access.

 

If you do try reading it, the stuff likely to be of most interest (and perhaps most readable) is in section 5 and to a lesser extent in some parts of part 6, while the recap in part 7 states ultimate results with minimal background.

Link to comment
Share on other sites

  • 2 weeks later...
3 hours ago, archer said:

 

And inadvertently ticks off a lot of his employees and customers by thanking them for financing his junket into space....

And how long has he been funding Blue Origin?
Tesla paid for Elon Musk to launch HIS personal car into space for a grand tour of our local orbit
some people need to get a life
of course since he sold all interest in Amazon
How many will stop buying from Amazon or drop their Prime accounts?
not many is my guess, or enough to make a dent like what happened to Disney+ over Gina

Link to comment
Share on other sites

  • 1 month later...

My local library is open again, so I'm getting caught up on space stories in Scientific American.

 

December 2020: Supernovae are more complicated than previously thought. When a really big star goes boom, not only are there multiple mechanisms for its core to collapse (all depending on the star's mass), but the star can blow off shells of material shortly before the explosion (maybe mere days), and there can be jets of plasma shot out from the collapsing core. If such a jet is fast enough (99.995% the speed of light!) and aimed in our direction, we see it as a gamma-ray burst. (That's the guess, anyway.) A slower jet might be caught in the shell of cast-off gas, heating it to produce a briefer but brighter supernova. If the core turns into a neutron star, its magnetic field can also interact with the expanding plasma of the explosion in various ways. Much more observation is needed to obtain a sufficient population of supernovae observed in greater detail -- including before the star actually explodes -- in order to work out the factors and processes that lead to these various results.

 

Dean Shomshak

Link to comment
Share on other sites

  • 2 weeks later...

The cover story for the April, 2020 issue of Scientific American was "New View of the Milky Way Galaxy." Astronomers have long been pretty sure the Milky Way is a barred spiral galaxy, but many details have been unknown -- notably, just how many spiral arms the galaxy has. The Bar and Spiral Legacy (BeSSeL) Survey attempted to answer that question by using radio astronomy to find the distance and direction of star-forming regions, where you find the hot, blue stars that define the spiral arms. (You can't see those regions throughout the galaxy: Dust obscures them. But those stars stimulate distinctive radio emissions that penetrate the dust... and by using a clever technique that turns a set of radio telescopes into a single telescope the size of the Earth, distance can be found directly by parallax.)

 

BeSSel finds that the Milky Way has four major arms, plus the fragmentary Local Arm that holds the Sun, and the 3 Kpc Arm, a ring that surrounds the central bar. The Sun is 8,150 +/- 150 parsecs from the center, and very close to the central plane of the galaxy. Here's a,link to the BeSSel report:

 

  • Results | The Bar and Spiral Structure Legacy Survey

    bessel.vlbi-astrometry.org/results

    This image of the Milky Way is based on 200 trigonometric parallaxes for masers in massive star forming regions from two large radio astronomy projects, the Bar and Spiral Structure Legacy (BeSSeL) Survey and the Japanese VLBI Exploration of Radio Astrometry (VERA) to survey the Milky Way from the inside out.

It has a gorgeous illo of the Milky Way based on the results, but it exceeds the size limit for the forum software.

 

Dean Shomshak

 

Link to comment
Share on other sites

Heard on All Things Considered the other day that the little helicopter has also performed well, scouting the route for Perseverance to take.

 

NASA is already working on another exo-helicopter... to fly on Titan! Low gravity + dense atmosphere means this one can be the size of a small car. But I imagine that building something that can function in such a cold environment will be a challenge.

 

Dean Shomshak

 

 

Link to comment
Share on other sites

Why is the solar corona so hot?

 

I don't think there's anything really new here, but it's a solid discussion.  And, I got acquainted with the author at a scientific meeting back in 1988, where he gave a talk after he slept under a bridge after being too inebriated to find his lodgings.  It was a good talk, too.

Link to comment
Share on other sites

  • 3 weeks later...
  • 2 weeks later...
  • 4 weeks later...

NOVA has been showing another astronomy m ini-series, "Universe Revealed," with episodes about Stars, the Milky Way, Alien Worlds, Black Holes, and (upcoming) the Big Bang. The CGI has been pretty. Milky Way and Alien Worlds had some information that was new to me, such as that the GAIA mission found a population of stars that orbit gthe Milky Way in retrograde, from which astronomers infer a galaxy (dubbed GAIA-Enceladus) that the Milky Way absorbed several billion years ago.

 

But the programs are marred by not enough airtime spent explaining why astronomers believe various results are true, and too much airtime on astronomers waving their arms while saying how amazing something is. Plus the usual banalities about Knowing Where We Came From and Why It Matters. (Note to science program writers: We wouldn't be watching if we didn't already think it was cool and it mattered. So don't waste our time selling the subject.) Some attempts to explain things in "common person" terms, such as comparing black holes to waterfalls, were more bizarre than useful. And some information was, if not false, then sufficiently lacking in context that I consider it misleading.

 

Maybe all the background explanations are given in supplemental material online, making the aired program a sort of extended trailer to entice people to the real content. I didn't look to see, because I would still consider that bad writing. All in all, "Universe Revealed" has been a disappointment.

 

Dean Shomshak

 

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...