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#101 2022-01-27 10:03:01

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 12,075

Re: Physics Topics

In pursuing the history of the evolution of the American football, Google suggested:

https://www.wilson.com/en-us/blog/footb … l-football

Among the details reported in the article at this site is that the 2,500 official NFL game balls manufactured at the company site are ** all ** hand made by 20 crafts people.

The history clearly states that the shape of the American football began in earnest when the forward pass was authorized (ca 1909)

At that point changes were introduced to improve the aerodynamic performance of the shape.

What i am arguing in this sequence, is that while those involved in shaping the football would have had no knowledge of physics or any other science, they ** would ** have been guided by Ma Nature to build products that obeyed Her laws.

By happy coincidence, and certainly without anyone involved being in any way aware of it, it appears (to me at least) that the makers and players together drove the shape toward maximum possible stability in the Z axis

(th)

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#102 2022-02-09 13:23:09

tahanson43206
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Registered: 2018-04-27
Posts: 12,075

Re: Physics Topics

This question would be one that might fit better into the Quora stream, but I am not a member there.

Besides, it is MUCH more applicable to NewMars than it is to most other online discussion groups.

Given a satellite in orbit, such as Phobos....

Given a ballistic launcher, such as the one envisioned by Dr. John Hunter (numerous citations are available in the forum archive) ...

Given a payload launched from Mars at escape velocity directly in the path of Phobos, offset by one kilometer (leading or trailing does not matter).

Then the payload will pass by Phobos at a velocity that is reduced by the pull of gravity of Mars, and with residual velocity sufficient to allow escape from Mars.

Question: If a tether is strung from Phobos so that a capture net is in the path of the payload, and the capture is successful ...

Then:

1) The payload will draw the tether taut as it attempts to continue it's movement away from Mars
2) The tether will stretch (slightly) under the load but will retain it's integrity
3) The payload will be drawn into a spiral around Phobos which will ultimately result in arrival at the surface of Phobos

Assume that the tether length and attachment point are chosen so that the payload impacts Phobos directly in the line-of-flight.

If the mass of the payload is one ton, what is the amount of momentum that will be given to Phobos at the moment of impact?

There are two vectors that I am sure of ...

a) The payload is stationary with respect to the orbital path of Phobos, since it is rising perpendicular to the surface of Mars
b) The payload has momentum along a line perpendicular to the surface of Mars

Phobos will have to provide momentum to the payload so that the payload is moving at the same velocity as Phobos along it's orbit

The payload will impart an outward momentum to Phobos since Phobos will have captured the payload on it's way out.

What is the resultant momentum felt by Phobos?

It is slowed and it is lifted simultaneously.

What is the resultant?

This question would have practical application by Dr. John Hunter, if a solution can be discovered.

As things stand, while his launcher can lift a payload above the Earth surface, the package must include a solid fuel rocket to achieve horizontal velocity.

If a tether from an orbiting station can capture the payload as described above, then there would be a resultant momentum experienced by the orbiting station.

I am wondering how that scenario would play out.

Note: there is torque at play as well.  If the object is Phobos, then that torque would tend to rotate Phobos in the direction the tether is winding.

(th)

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#103 2022-02-09 18:30:26

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 26,803

Re: Physics Topics

The debri capturing net of the I think Japanese unit might serve as an estimate of what we need for strength of what we would need for a phobos tether net system.

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#104 2022-02-17 09:58:27

tahanson43206
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Registered: 2018-04-27
Posts: 12,075

Re: Physics Topics

As reported in Housekeeping, my work in the early days of the forum brings "ancient" discussions into view.

The one I'm commenting upon here is/was about mechanical catapults/trebuchet machines ...

Somewhere buried in all the posts about catapults, there is a discussion by a member who considered the mechanical catapult / Trebuchet machine as a possible mechanism to lift payloads to orbit.

While the member did not appear to have any engineering or materials science background, what he ** did ** have was a calculator and the equations for simple levers, so he computed that he (theoretically) could toss a ton into orbit using a lever with an 80 meter swing arm, a 2 meter short arm, and a mass in the hundreds of thousands of tons.

Out of curiosity, I asked Google what records might have been achieved on Earth.  To my surprise, the current record was set as recently as a year ago:

Who
SIERRA NEVADA BREWING CO
What
133.75 METRE(S)
Where
UNITED STATES (CHICO)
When
02 MARCH 2021

The farthest distance thrown by a trebuchet (with projectile weight of 20kg and over) is 133.75 m (438.81 ft), and was achieved by Sierra Nevada Brewing Company (USA) in Chico, California, USA, on 2 March 2021.

The projectile was in the air for approximately 5.53 seconds.
All records listed on our website are current and up-to-date. For a full list of record titles, please use our Record Application Search. (You will need to register / login for access)

Comments below may relate to previous holders of this record.

While 438+ feet is impressive (to me at least) it falls short of Earth orbit.

The limiting factor (that ** I ** am aware of) is the strength of simple cohesive bonds between the atoms of whatever material is chosen for the swing arm.

The limit is similar to the limit imposed on developers of Space Elevators ... electronic cohesive bonds are simply not strong enough to support such ventures.

***
JoshNH4H was (is) noted for posing challenging problems of physics.

In the spirit of JoshNH4H, I will offer this challenge:

Design a catapult swing arm made of ordinary real-Universe materials, able to exceed the performance of "normal" (unaugmented) material.

To achieve this improved performance, employ the strength of magnetic fields to supplement the purely electrostatic fields of normal chemical cohesion.

Design a swing arm that can maintain structural integrity while subjected to bending torque that exceeds ordinary electrostatic chemical bonds, using a flow of current that produces a magnetic field that acts to compress the material (whatever is is) in the longitudinal direction, so that it maintains it's integrity despite being stressed beyond it's normal breaking point.

(th)

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#105 2022-03-12 18:46:19

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 4,782

Re: Physics Topics

New quantum gravity sensor could someday peel away the surfaces of other worlds
https://www.space.com/atomic-hourglass- … reakthroug

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#106 2022-03-18 07:12:58

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 4,782

Re: Physics Topics

Moon's orbit proposed as a gravitational wave detector

https://www.spacedaily.com/reports/Moon … r_999.html

With these "natural detectors" in the microhertz frequency range, Blas and Jenkins were able to propose a new form of studying gravitational waves emitted by the distant universe. Specifically, those produced by the possible presence of transitions in highly energetic phases of the early universe, commonly seen in many models.

"What is most interesting perhaps is that this method complements future ESA/NASA missions, such as LISA, and observatories participating in the Square Kilometer Array (SKA) project, to reach an almost total coverage of the gravitational waves from the nanohertz (SKA) to the centihertz (LIGO/VIRGO) frequency ranges. This coverage is vital to obtaining a precise image of the evolution of the universe, as well as its composition", Diego Blas explains.

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#107 2022-03-31 17:41:46

tahanson43206
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Registered: 2018-04-27
Posts: 12,075

Re: Physics Topics

Fusion is under discussion in multiple topics ... this post is an attempt to bring a few of the most interesting reactions into view...

Elementary review of Fusion principles:


Per Google:

Deuterium fusion - Wikipedia
en.wikipedia.org › wiki › Deuterium_fusion

See results about
Deuterium fusion
Deuterium fusion, also called deuterium burning, is a nuclear fusion reaction that occurs in stars and some substellar objects, in which a deuterium nucleus and a proton combine to form a helium-3 nucleus.



per Google:

The involved nuclear reaction here when helium-3 and deuterium fuse creates normal helium and a proton, which wastes less energy and is easier to contain. Nuclear fusion reactors using helium-3 could therefore provide a highly efficient form of nuclear power with virtually no waste and no radiation.
Jan 30, 2016
Helium-3 Power - ExplainingTheFuture.com
www.explainingthefuture.com › helium3

Related per Google:

Nuclear Fusion - HyperPhysics
hyperphysics.phy-astr.gsu.edu › hbase › NucEne › fusion
The deuterium-deuterium fusion divides its output energy between neutrons and protons. The proton fraction interacts by the electromagnetic force with the ...

(th)

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#108 2022-03-31 18:32:46

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 12,075

Re: Physics Topics

The purpose of this post is to invite contributions that might be interesting to a few forum members, and perhaps helpful to a few readers.

For Calliban re Neutron reflection ... I am offering a post/inquiry about neutron reflection in the Physics topic.

I'm hoping a few forum members, and perhaps a few readers, will be interested to learn how neutrons might be reflected, since they are (by definition) uncharged.  I bring this up in the Hybrid topic because ( I am hoping ) neutron reflection might have a role to play in enhancing the movement of neutrons through material to be fused.

In earlier posts, you have reported on several ways of collecting thermal energy from neutrons, and I am sure those will remain important components of any successful energy producing fusion device.  However, if neutron reflection is more than just a theoretical possibility, then perhaps it might have a role to play.

(th)

(th)

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#109 2022-04-10 04:04:47

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 4,782

Re: Physics Topics

We don't seem to have a Gravity-Waves topic on the newmars discussion forum, perhasps it fits into one of those exotic fringe science topics

Ten new gravitational waves found in LIGO-Virgo's O3a data

https://www.spacedaily.com/reports/Ten_ … a_999.html

In the last seven years, scientists at the LIGO-Virgo Collaboration (LVC) have detected 90 gravitational waves signals. Gravitational waves are perturbations in the fabric of spacetime that race outwards from cataclysmic events like the merger of binary black holes (BBH). In observations from the first half of the most recent experimental run, which continued for six months in 2019, the collaboration reported signals from 44 BBH events.

But outliers were hiding in the data. Expanding the search, an international group of astrophysicists re-examined the data and found 10 additional black hole mergers, all outside the detection threshold of the LVC's original analysis. The new mergers hint at exotic astrophysical scenarios that, for now, are only possible to study using gravitational wave astronomy.

"With gravitational waves, we're now starting to observe the wide variety of black holes that have merged over the last few billion years," says Physicist Seth Olsen, a Ph.D. candidate at Princeton University who led the new analysis. Every observation contributes to our understanding of how black holes form and evolve, he says, and the key to recognizing them is to find efficient ways to separate the signals from the noise.

Notably, the observations included phenomena from both high- and low-mass black holes, filling in predicted gaps in the black hole mass spectrum where few sources have been detected. Most nuclear physics models suggest that stars can't collapse to black holes with masses between about 50 and 150 times the mass of the sun. "When we find a black hole in this mass range, it tells us there's more to the story of how the system formed," says Olsen, "since there is a good chance that an upper mass gap black hole is the product of a previous merger."

Nuclear physics models also suggest that stars with less than twice the mass of the sun become neutron stars rather than black holes, but almost all observed black holes have been more than 5 times the mass of the sun. Observations of low-mass mergers can help bridge the gap between neutron stars and the lightest-known black holes. For both the upper and lower mass gaps, a small number of black holes had already been detected, but the new findings show that these types of systems are more common than we thought, Olsen says.

The new findings also include a system that scientists had never seen before: A heavy black hole, spinning in one direction, engulfing a much smaller black hole that had been orbiting it in the opposite direction. "The heavier black hole's spin isn't exactly anti-aligned with the orbit," Olsen says, "but rather tilted somewhere between sideways and upside down, which tells us that this system may come from an interesting subpopulation of BBH mergers where the angles between BBH orbits and the black hole spins are all random."

Identifying events like black hole mergers requires a strategy that can distinguish meaningful signals from background noise in observational data. It's not unlike smartphone apps that can analyze music-even if it's played in a noisy public place-and identify the song that's being played.

Just as such an app compares the music to a database of templates, or the frequency signals of known songs, a program for finding gravitational waves compares the observational data to a catalog of known events, like black hole mergers.

To find the 10 additional events, Olsen and his collaborators analyzed LVC data using the "IAS pipeline," a method first developed at the Institute for Advanced Studies and spearheaded by Princeton astrophysicist Matias Zaldarriaga. The IAS pipeline differs in two important ways from the pipelines used by the LVC.

First, it incorporates advanced data analysis and numerical techniques to improve on the signal processing and computational efficiency of the LVC pipelines. Second, it uses a statistical methodology that sacrifices some sensitivity to the sources that LVC approaches are most likely to find in order to gain sensitivity to the sources that LVC approaches are most likely to miss, such as rapidly spinning black holes.

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#110 2022-04-26 18:48:51

tahanson43206
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Registered: 2018-04-27
Posts: 12,075

Re: Physics Topics

For Mars_B4_Moon re #109

Thank you for your comprehensive post about Gravity Waves, and the research into their nature made possible by the new ultra-sensitive detectors!

***
This post is not nearly as comprehensive, or significant.

It follows from a conversation with kbd512 in a topic about how humans can fill in for Ma Nature, when She fails to meet the needs of people living in various locations on Earth.

kbd512 expressed a note of skepticism about the idea of transporting water using Hydrogen filled dirigibles.

Since the NewMars forum is a place where ideas can sprout, and sometimes grow in a nutrient bath of member commentary, I take the skepticism of kbd512 as an incentive to try to think more about the problem.

Ma Nature shows how to do most things that need doing.  She shows (for example) how to lift water molecules out of the liquid ocean, motivated ONLY by the action of photons of light, and to transport those molecules all over the Earth under the influence of other photons.

When humans have imagined themselves trying to emulate the achievements of Ma Nature, to this point, every effort (that I know about) has fallen short.

That doesn't mean that someone, somewhere, has not achieved mastery of desalination using photons, and delivery of those water molecules to where they are needed using other photons.  it simply means that ** I ** don't know about it.

However, in the absence of knowledge of the success of others, I am inspired by the skepticism of kbd512 to ask a couple of questions ...

How is it possible for a water molecule to float up into the atmosphere and stay there in the first place?

I'm assuming the molecular weight of the water molecule must be ** just right ** so that it mixes easily and comfortably with oxygen molecules and nitrogen molecules that comprise the greater part of the atmosphere, but would be delighted if a NewMars member can find facts to support that theory, or to otherwise explain the observed phenomenon.

On the subject of dirigibles for transport of water, the skepticism of kbd512 inspired me to ask .... what are we trying to do ? Is there a simpler way to to it?

A dirigible (from human history) has a mission of transporting mass from one place to another by taking advantage of the lesser molecular weight of hydrogen or helium, as compared to the aforementioned oxygen and nitrogen molecules.

A dirigible (again from human history) has a metal frame, and fabric or other containers to hold Hydrogen or Helium.

But in this case, what we want to do is to guide water molecules from the ocean to where they are needed.  In most cases (that I can think of) the desired destination for such water molecules is on land.   If we reduce a "dirigible" (in the context of transporting water) to it's essence, we would have hydrogen lifting water molecules inside a membrane of almost infinitesimal thickness, but never-the-less, able to prevent exit of hydrogen molecules.

So now I am imagining a sausage shape water transporter, able to keep a shipment of water molecules more or less in containment, while the entire assembly is pulled from the point of origin to the destination.

A well known mechanism for "liberating" water from an atmosphere is cooling .... as it happens, water will precipitate before hydrogen, so it should be possible to extract a shipment of water molecules from a sausage shaped shipping container, while the hydrogen remains available to carry the sausage back to the point of origin.

(th)

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#111 2022-04-26 19:04:36

tahanson43206
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Registered: 2018-04-27
Posts: 12,075

Re: Physics Topics

http://katkam.ca/

I keep the web site above "lit" on a spare screen when I am working on a particular work station, between times when I need the fourth screen.

It almost ** always ** shows suspended water in the sky.  The form of the suspended water varies from day to day, and often from hour to hour.

All that suspended water is floating freely at the whim of Ma Nature.

Following on from the post before this one:

1) What would a manmade cloud look like?

2) How many tons of water are present in a cloud - there are many types of cloud, so there is (probably) not one answer

3) What is the maximum density of water that can be carried in a cloud?

4) How does density of water in fog (which we humans can experience directly) compare to that in a cloud?

If thermal energy is required to keep water molecules "happy" while enjoying the "companionship" of adjacent non-water molecules, how much thermal energy is required?

5) If water molecules are mixed with hydrogen molecules, what happens?  I've not read or heard ** anything ** about that particular combination.

(th)

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#112 2022-05-04 17:18:13

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 4,782

Re: Physics Topics

Stanford scientists describe a gravity telescope that could image exoplanets

https://www.spacedaily.com/reports/Stan … s_999.html

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#113 2022-05-04 18:03:10

tahanson43206
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Registered: 2018-04-27
Posts: 12,075

Re: Physics Topics

For Mars_B4_Moon re #112

Thanks for the link to the story about using the Sun as a Gravitational Lens.

The technique (apparently) requires a Hubble class telescope to be located 14 AU from the Sun.

[ext was supposed to have been copied but nothing showed up.

The text intended for display estimated the time it would take to deploy a telescope at the "magic" point as measured in decades, using current technology.

If faster propulsion systems come online, this observational technique might become feasible.

However, perhaps Jupiter could provide some benefits.  I hope this research continues, using other massive bodies to focus rays from distant objects.

(th)

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#114 2022-05-04 19:43:14

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 26,803

Re: Physics Topics

Gravitational lensing something that I think Eistien said was possible, is not a new thing but has been used to see what is behind at greater distances as the light is pulled from its straight line due to the curvature of space that occurs by the large suns that are in the pathway.

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#115 2022-05-04 19:50:13

tahanson43206
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Registered: 2018-04-27
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Re: Physics Topics

For those who might not have time to read the article, to build on the comment by SpaceNut in Post #114, the difference in this technique is that the research seems to show that continents might be visible on planets around distant stars.  That is an entirely different proposition from seeing a star billions of light years away due to the kind of lensing that (I think) SpaceNut is talking about.

(th)

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#116 2022-05-04 19:56:12

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 26,803

Re: Physics Topics

By positioning a telescope, the sun, and exoplanet in a line with the sun in the middle, scientists could use the gravitational field of the sun to magnify light from the exoplanet as it passes by.

Rather than the far off suns called stars that I described, we are using the local sun instead.

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#117 2022-05-12 09:13:23

tahanson43206
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Posts: 12,075

Re: Physics Topics

In another topic, the question of how to pull moisture from the air without "cloud seeding" is in discussion...

Google found this report on research on hurricanes ... the tentative conclusion seems to be that hurricanes power themselves (in part) by drawing energy from the moisture already present in the air mass where they grow.  The process of precipitation (according to the study) releases thermal energy that powers the hurricane.  The researchers found that after a hurricane passes, the air left behind is dryer.  To me, this is not surprising, but it ** is ** good to have scientific measurements of before-and-after conditions to add to understanding.

https://physicsworld.com/a/how-hurrican … rainwater/

The mystery of how tropical cyclones deliver colossal amounts of rainwater over long periods of time may have been solved by an international team of atmospheric physicists. The team suggests that – rather than relying on ongoing evaporation to replenish rainwater – these powerful storm systems suck pre-existing moisture out of the air through which they travel.

Tropical cyclones – or hurricanes, as they are called in the northern hemisphere – are capable of delivering huge amounts of rain that can do more damage than the high winds associated with the storms. The mean precipitation from a typical Atlantic hurricane, for example, lies at around 2 mm/h – and this rate can be sustained for days on end. What is puzzling about this, however, is that it is considerably faster than the typical rate of tropical oceanic evaporation. This means that a hurricane’s moisture stocks must be replenished from something other than ongoing evaporation, otherwise a typical storm would run dry within a day.

Imported moisture
Traditionally, studies of the water budget of tropical cyclones have been focused only on the area within 400 km of the storm’s centre – the part of a cyclone thought to receive the majority of the ocean-derived heat that powers it. In this region, the local evaporation of water from the sea can only account for around 10–20% of the total rainfall. So, it has been supposed, the additional moisture must be being imported from further out, up to 2000 km from the eye of the storm – and well beyond the area of the storm in which rain falls. The exact mechanism that could import water vapour like this has not been clear. Pressure gradients more than a few hundred kilometres from the storm’s centre, for example, are inadequate to drive outlying moist air towards the centre.

To investigate further, physicist Anastassia Makarieva of the Petersburg Nuclear Physics Institute in Russia and colleagues looked at the moisture dynamics of north Atlantic hurricanes out to 3000 km from their centre. First, the researchers considered the radial pressure distribution, relative humidity and temperature of the hurricane boundary layer, and calculated that – even at their wider scale of interest – the storm’s rainfall cannot be supported by evaporation alone.

Dry footprint
Next, the team examined North Atlantic atmospheric moisture and rainfall data from 1998 to 2015 recorded by the Tropical Rainfall Measuring Mission satellite and NASA’s Modern Era Retrospective Re-Analysis for Research and Applications programme. By comparing conditions during hurricanes with the surrounding hurricane-free periods, the researchers were able to show that hurricanes leave in their wake a “dry footprint”, in which rainfall is suppressed by up to 40%.

Given this – and the failure of evaporation to adequately explain how hurricanes refuel – the researchers propose instead that hurricanes gobble up pre-existing moisture stocks from the atmosphere as they move, with the rain potential of the hurricane being directly proportional to the storm’s velocity relative to the surrounding air flow.

“Hurricanes must move to sustain themselves,” Makarieva says, concluding: “Hence, how they move and consume the pre-existing atmospheric water vapour is key to predicting their intensity.” The researchers propose that – rather than being driven by heat extracted from the ocean – hurricanes are instead powered by releasing the potential energy of the water vapour previously accumulated in the atmosphere that they pass through.

Moisture-robbing winds
They suggest this could explain why tropical cyclones do not occur in regions like the Brazilian coast where there are persistent, landward winds that remove water vapour from over the ocean – thereby robbing the potential storms of their drive and fuel source.

Patrick Fitzpatrick, a geoscientist from the Mississippi State University who was not involved in this study, comments: “Quantitative precipitation forecasting of tropical cyclones still lacks skill, and is worthy of research since these storms’ inland flash flooding is a major cause of casualties and property damage”. He believes that further investigation of these new climate budget implications – considering the local upstream conditions and storm motion – are needed.

Kevin Trenberth – a meteorologist at the US National Center for Atmospheric Research – is sceptical, however, suggesting the researchers are too idealistic in their view of hurricanes, treating them as symmetrical and two dimensional, and overlooking their size variability and spiral arm bands that bring moisture into the storm from about four times the radius of the rainfall area. The mismatch between evaporation and precipitation rates for anything greater than light rain has already been established, he says, adding: “It is correct that the moisture has to come from somewhere, and movement of the storm helps, but that does not help storms that move slowly or not at all.”

With their initial study complete, the researchers are now working to describe how hurricanes might develop over time by the condensation of water vapour.

The research is described in the journal Atmospheric Research.

Want to read more?

The tentative conclusion I draw from this work is that Ma Nature is showing that there is energy to be collected from water laden air masses, if water can be caused to precipitate.  The exact mechanism is not clear (to me for sure) but I ** think ** Ma Nature is showing that there is an energy reward for humans who can figure out how to cause moisture to fall out of clouds without a hurricane as the mechanism.

Those humans (who are members of this forum) who like to harvest energy when it is passing by unused, may be able to think of a way to harvest that energy and deliver fresh, desalinated, potable water as a welcome byproduct.

If there is a reader who would like to contribute, see Recruiting topic.

(th)

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#118 2022-05-13 08:16:50

tahanson43206
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Registered: 2018-04-27
Posts: 12,075

Re: Physics Topics

The focus of this post is the physics of collecting water from fog...

Google
how do redwoods get water from fog

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About 7,280,000 results (0.55 seconds)
Fog sustains redwoods and the ecosystems they support, including life in the creek. Specialized redwood tree needles catch the fog. The fog drips down through the canopy and replenishes the water in the creek. The amount of summertime fog has decreased which has left streams low and warm.Sep 23, 2021

Fog, Redwoods and a Changing Climate - National Park Servicehttps://www.nps.gov › articles › fog-redwoods-and-a-cha...

it appears that "specialized" physical structures can encourage water to condense out of fog.

It seems possible that such structures might encourage water to condense out of a cloud, into a receptacle in a flying drone.

(th)

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#119 2022-05-15 06:13:48

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 4,782

Re: Physics Topics

'Gravity's Grin'

https://apod.nasa.gov/apod/ap220511.html

The arcs are optical images of distant background galaxies lensed by the foreground group's total distribution of gravitational mass. Of course, that gravitational mass is dominated by dark matter. The two large elliptical "eye" galaxies represent the brightest members of their own galaxy groups which are merging. Their relative collisional speed of nearly 1,350 kilometers/second heats gas to millions of degrees producing the X-ray glow shown in purple hues.

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#120 2022-05-23 06:03:28

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 4,782

Re: Physics Topics

Airbus to further develop LISA gravitational wave observatory mission

https://www.spacedaily.com/reports/Airb … n_999.html

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#121 2022-05-24 11:26:45

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 2,236

Re: Physics Topics

Another experiment with microwave power beaming technology shows promising results.
https://oilprice.com/Energy/Energy-Gene … nergy.html

This experiment used a 10GHz beam and reported total transmissiin efficiency up to 70%.

Last edited by Calliban (2022-05-24 11:28:47)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#122 2022-05-24 14:23:24

tahanson43206
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Posts: 12,075

Re: Physics Topics

For Calliban re #121

Thanks for reporting this research!  The one kilometer test range is useful for something like the electric tractors that John Deere is developing.  The automatic shutoff feature, to protect birds from radiation, sounds handy, but it might be a challenge for farms, where birds are frequent visitors.

Still, there might be solutions to that problem as well.  It sure would beat the hassle of kilometer long cables.

(th)

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#123 2022-05-25 11:40:55

tahanson43206
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Registered: 2018-04-27
Posts: 12,075

Re: Physics Topics

This is primarily for SpaceNut regarding the magnetic properties of rust ...

In your answer to a question I had posed in Housekeeping, you offered the opinion that rust is not magnetic.

I was curious as to what might be going on, so asked Google for help.  Apparently the oxygen atoms consume most of the magnet susceptibility of the iron atoms, so you were right in the 80/20 sense.  However, it turns out that even though the magnetic attraction of rust to a magnetic field is less than would be the case if there were no oxygen atoms present, it is NOT zero.

https://www.youtube.com/watch?v=rTR-Mm_lQA4

By studying this video, and waiting to the punchline at the end, you will see that my original idea of separating iron particles (rust in the case of your ground water) ** does ** appear to work if the magnetic field is strong enough.

My guess, and only experiment would confirm or falsify the guess, is that a strong permanent magnet in the base of a column of your ground water would attract some of the rust particles.  How much would be answered by experiment.

If you are in the mood to carry out an experiment,  I would most definitely be interested in the results.

I realize you may not have the equipment on hand, so this may be an activity for another time.

On the ** other ** hand, an old motor might contain permanent magnets that could be adapted for the purpose.

(th)

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#124 2022-05-26 04:30:07

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 4,782

Re: Physics Topics

I could not find any topic with  SpinLaunch or Vacuum Launches or Centrifuge Launched Satellite, it be subjected to a lot of G's

Rockets not needed?

' SpinLaunch has successfully tested a new way of getting into space. It says it can use a vacuum centrifuge to fire satellites weighing up to 200kg into orbit '

https://www.freethink.com/space/spinlaunch-video

Last edited by Mars_B4_Moon (2022-05-26 04:30:25)

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#125 2022-06-22 12:46:38

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 12,075

Re: Physics Topics

In one of Void's topics, Calliban recently made an observation about the use of water as a propellant.

Rather than disturb the elegant flow of Void's topic, I am inviting Calliban (and anyone else who might be interested)
to extend the conversation here...

tahanson43206 wrote:

For Calliban re #322

This may be a departure from Void's topic, so it may be better to continue in another topic.... however, my question is:

Why is disassociation of the water molecule a problem?  Both hydrogen and oxygen are rendered as lower molecular weight entities, so they ? should ? provide higher ISP (a) and (b) once ionized, they should be subject to electric (probably magnetic) acceleration to achieve even greater ISP.

If another topic is preferred by Void, I'd like to offer the Physics topic.

(th)

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