Coffee House Musing

Adding to everything you listed, the Fermi Gamma-ray Space Telescope in orbit along several others, orbital X-ray observatories, detecting gamma-ray bursts and all sorts of other high energy phenomena. A global network is coordinating observations at a wide range of wavelengths and energies and I think I read that they will also coordinate with the LIGO and Virgo gravitational wave observatories.All these observatories coordinating to capture rapid transient astronomical events has opened up fertile new areas of research.Later this year the James Webb Space Telescope will be launched and should blow all our minds.It even turns out using those advanced computer analysis of the gravitational wave signal reveals lots of additional fine resolution data from what initially looked like noise around the signal.I am planning to live long enough to see this true golden age of astronomy!

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In 1975 I bought a Questar telescope that was only 3.5 inches in diameter. It was laughingly small but also considered to be one of the best pieces of engineering to be produced in the 20th century. Visible eye observation is a dream with it. I can see the Giant Red spot and the Cassini Division and non-astrological viewing is mind blowing.Astrophotography with film was tricky but still fun and I remember people cooling their film with dry ice, but I can't remember why right now. I think it was in the 80's after the Voyager missions that CCD devices started to become available to the amateur astronomers.The problem with film was always that you had to wait for the film to be developed to see if you got anything. Digital gives you instant feedback on success or failure.In my own case, I was happy to discover that photography through my Questar with a DSLR produces images that are far superior to my film days with far less fussing around.

Well, he shouldn't quit his day job!

Today there were several articles in my SciTechDaily news feed about clever, innovative astronomical studies to refine the measurements of the expansion rate of the Universe, plus, is it uniform in every direction? And using gravity waves, specifically created by merging neutron stars, to tell us about all about these stars including the orientation of of the rotating pair. Gravitational-Wave Scientists Brilliant New Method to Refine the Hubble Constant – The Expansion and Age of the Universe

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A team of international scientists, led by the Galician Institute of High Energy Physics (IGFAE) and the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav), has proposed a simple and novel method to bring the accuracy of the Hubble constant measurements down to 2%, using a single observation of a pair of merging neutron stars.

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I think this was a pretty good article about this study with a lot of good background into the questions we are trying to ask about dark energy that might clues to which questions might increase our understanding of what is observable and how to do that. Dark Energy Experiment 16 Years in the Making Could Illuminate Origin, Evolution, Fate of Universe

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A map of stars and sound
“HETDEX is very ambitious,” Ciardullo said. “It’s going to observe a million galaxies to map out the structure of the universe going over two-thirds of the way back to the beginning of time. We’re the only ones going out that far to see the dark energy component of the universe and how it’s evolving.”

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Both these articles are fairly well written. Occasional articles in their list I would say the best part was the title. Some had whole paragraphs repeated in the same article, but every day I find good articles about studies and findings in the branches of science and technology that interest me. One thing I like about SciTechDaily is a nice list of references for every article.It's interesting reading while my imaging computer is processing thousands of images every day.A question just occurred to me, Do gravity waves have an effect like the electromagnetic red-shift from cosmic expansion?Another question, why is the speed of gravity the speed of light? Is it coincidence or is there an obvious link between gravity and light that I am overlooking?

Thanks, good answers!I'm anticipating the development of the field of gravitational wave astronomy that will open new views of the Universe the same ways that light, radio, X-ray, and Gamma-ray astronomy have. I can imagine the gravity data being used to create visible images of the Universe similar to the images created using various parts of the electromagnetic spectrum. I am disappointed that I will not live long enough to see it developed into a mature branch of astronomy.

One of the positive features of science, that is often unrealized by non-scientists, is the tradition and responsibility to train the next generations of aspiring scientists. This is not just giving students a sampling of the accumulated knowledge previously acquired by scientists in a specific field, but how to engage in science and apply the scientific method to understand observations.

Today I read an interesting article on SciTechDaily and learned about a major global astronomy collaboration. Mapping the Universe’s Earliest Structures and Dark Matter Distribution With COSMOS-Webb

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When NASA’s James Webb Space Telescope begins science operations in 2022, one of its first tasks will be an ambitious program to map the earliest structures in the universe. Called COSMOS-Webb, this wide and deep survey of half-a-million galaxies is the largest project Webb will undertake during its first year.

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With more than 200 hours of observing time, COSMOS-Webb will survey a large patch of the sky—0.6 square degrees—with the Near-Infrared Camera (NIRCam). That’s the size of three full moons. It will simultaneously map a smaller area with the Mid-Infrared Instrument (MIRI).

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I love that they describe it as a large patch of sky, but to us it seems like an awfully small patch of sky.

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It’s a large chunk of sky, which is pretty unique to the COSMOS-Webb program. Most Webb programs are drilling very deep, like pencil-beam surveys that are studying tiny patches of sky,” explained Caitlin Casey, an assistant professor at the University of Texas at Austin and co-leader of the COSMOS-Webb program. “Because we’re covering such a large area, we can look at large-scale structures at the dawn of galaxy formation. We will also look for some of the rarest galaxies that existed early on, as well as map the large-scale dark matter distribution of galaxies out to very early times.”

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(Dark matter does not absorb, reflect, or emit light, so it cannot be seen directly. We know that dark matter exists because of the effect it has on objects that we can observe.)

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COSMOS-Webb will study half-a-million galaxies with multi-band, high-resolution, near-infrared imaging, and an unprecedented 32,000 galaxies in the mid-infrared. With its rapid public release of the data, this survey will be a primary legacy dataset from Webb for scientists worldwide studying galaxies beyond the Milky Way.

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This is so cool!!! They are looking at this patch of sky over the entire electromagnetic spectrum.

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The COSMOS survey began in 2002 as a Hubble program to image a much larger patch of sky, about the area of 10 full moons. From there, the collaboration snowballed to include most of the world’s major telescopes on Earth and in space. Now COSMOS is a multi-wavelength survey that covers the entire spectrum from the X-ray through the radio.

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Because of its location on the sky, the COSMOS field is accessible to observatories around the world. Located on the celestial equator, it can be studied from both the northern and southern hemispheres, resulting in a rich and diverse treasury of data.

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“COSMOS has become the survey that a lot of extragalactic scientists go to in order to conduct their analyses because the data products are so widely available, and because it covers such a wide area of the sky,” said Rochester Institute of Technology’s Jeyhan Kartaltepe, assistant professor of physics and co-leader of the COSMOS-Webb program. “COSMOS-Webb is the next installment of that, where we’re using Webb to extend our coverage in the near- and mid-infrared part of the spectrum, and therefore pushing out our horizon, how far away we’re able to see.”

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They have some ingenious methods of mapping dark matter halos around galaxies.Some humans can achieve amazing things working together. A question occurs to me that maybe Son Goku can answer or give us the leading hypothesis.

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Why doesn't dark matter clump together like regular matter does, in denser and denser clumps? I usually see dark matter described as more amorphous halos around galaxies. Is the repulsive force of dark energy acting more strongly on dark matter than normal matter?

I don't understand what you are saying here. Are you talking about matter forming compounds with shared electrons or some other aspect of electromagnetic force, like magnets attract each other?I was thinking of the clumping of matter due to gravitational attraction, like the extreme clumping we see in planets, stars, and black holes. Do you think dark matter can form black holes and/or is it more concentrated where we see mass concentrated?I guess what I am asking is, is there an hypothesized explanation, for why dark matter, that we can only detect by how it gravitationally effects the stuff we can see, does not seem to form extreme concentrations of dark matter? Or does it, and I just misunderstood the descriptions? What would keep it a fog? Why doesn't it become more concentrated by its own gravitational attraction?

Great answers, thanks so much!!

I remember hearing dozens of hypotheses about every single aspect of how the Universe works and every aspect of cosmology, which is basically the same thing. I remember hearing hypotheses about what astrophysicists thought the effect would be on the expansion of the Universe with different proportions of matter. You seem to think there was a consensus, but there never was because we didn't have enough data. In science there are always scientists who question each other's work.Scientists propose explanations for observations and everyone talks about them for a while and they turned every which way to see if they work. Sometimes they work and every time someone someone figures out a new way to test it their new data confirms it. Sometimes the observations start to look like their hypothesis is incomplete or even wrong.If you only heard one thing constantly then you were listening to the wrong people.

Yeah, you can't do any of this without math, but it also takes precision observations. Most of our observational power has been developed since then, covering the whole electromagnetic spectrum, plus gravitational waves.

You seem to be pissed off because there are limits to our knowledge. That's why we have dozens of new specialized telescopes and observing satellites coming on line. We're learning more all the time.This is the golden age of astronomy!

This is the first solution to the problem of extinction level impacts that might actually work and that could work with much less warning time. Planetary Defense: Physicists Propose New Way To Defend Earth Against Cosmic Impacts

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However, one cannot discount the possibility of larger objects coming uncomfortably close to Earth in the near future: Apophis, with its 1,214-foot (370 meter) diameter, is due to make a close pass on Friday the 13th in April 2029, while Bennu, at 1,608 feet (490 m) in diameter, is expected to perform a similar pass in 2036. Though they are not anticipated to hit Earth, even relatively small changes in their orbit could cause them to enter gravitational pockets called “keyholes” that can place them on a more direct trajectory toward Earth.

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“If it goes through the gravitational keyhole, it will generally hit Earth on the next round,” Lubin said.

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Strategies for planetary defense have progressed from research into better methods for understanding the threats, to efforts to deflect potential hazards and change their orbits, including a strategy developed by Lubin’s group, which proposed the use of lasers to push threatening objects out of Earth’s way. (See their website for more information on laser-based planetary defense: DE-STAR)

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In two papers on the topic of terminal planetary defense submitted to the journal Advances in Space Research, accompanied by an opinion piece published in Scientific American, Lubin and co-researcher Alexander Cohen lay out a more proactive method for dealing with dangerous extraterrestrial space debris. The project is called PI, which affectionately stands for Pulverize It.

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Key to the PI strategy is the deployment of an array of penetrator rods, possibly filled with explosives, laid in the path of the asteroid to “slice and dice” the threatening object. The penetrator rods — about 4-12 inches (10-30 cm) in diameter and six to ten feet long — fragment the asteroid or comet nucleus as it crashes into them at extreme speed.

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Crucially, instead of deflecting the object, the strategy is to let the Earth take the hit, the researchers said, but first to disassemble the asteroid into smaller pieces — typically the size of a house — and let the fragments enter the Earth’s atmosphere. The atmosphere can then absorb the energy and further vaporize the house-sized pieces into small debris that do not hit the ground.

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UCSB Experimental Cosmology Group

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PI-Terminal Planetary Defense
Links to papers:
Detailed technical paper:
PI-Terminal Planetary Defense
arXiv archive link:
http://arxiv.org/abs/2110.07559
Scientific American Article:
Planetary Defense Is Good--but Is Planetary Offense Better? - Scientific American
UCSB Press Release 10-11-21:
Is Planetary Defense PI in the Sky? | The UCSB Current

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Space agencies around the globe should start planning tests. This would be a much more useful project for the billionaire rocket men than sending dimwits into space.