Mo's moderately interesting sci/tech thread

[Warren]

It's patent nonsense.

The film helps to keep its surroundings cool by absorbing heat from the air inside the box and transmitting that energy through the Earth’s atmosphere into outer space.

It's a straight up violation of the second law of thermodynamics. You can never power a system off of ambient heat. Waste heat is where energy goes to die.

[lunchstealer]

It's patent nonsense.

The film helps to keep its surroundings cool by absorbing heat from the air inside the box and transmitting that energy through the Earth’s atmosphere into outer space.

It's a straight up violation of the second law of thermodynamics. You can never power a system off of ambient heat. Waste heat is where energy goes to die.

It's not a closed system, and it sounds like all they're talking about is a collimated radiator. It is working off a temperature difference between air and space, which is a 300K+ difference. Directional radiation makes those little black-and-white spinny things in the bulbs work, so it's not like thermal radiation can't do work.

Still not sure the math works out on this, but there is a temperature differential to 'power' the engine, so it's not purely working on ambient heat in a closed system, which would legit be breaking the law.

[Aresen]

It's patent nonsense.

The film helps to keep its surroundings cool by absorbing heat from the air inside the box and transmitting that energy through the Earth’s atmosphere into outer space.

It's a straight up violation of the second law of thermodynamics. You can never power a system off of ambient heat. Waste heat is where energy goes to die.

It's not a closed system, and it sounds like all they're talking about is a collimated radiator. It is working off a temperature difference between air and space, which is a 300K+ difference. Directional radiation makes those little black-and-white spinny things in the bulbs work, so it's not like thermal radiation can't do work.

Still not sure the math works out on this, but there is a temperature differential to 'power' the engine, so it's not purely working on ambient heat in a closed system, which would legit be breaking the law.

The second law of thermodynamics is part of the cis white male patriarchy's conspiracy to keep infrared photons down!

[JD]

New Study Reveals Dark Matter May Have Predated the Big Bang

Ow, my brain!

[Warren]

New Study Reveals Dark Matter May Have Predated the Big Bang

Ow, my brain!

The novel study employs a simple mathematical framework to illustrate that dark matter may have been produced before the Big Bang. More specifically, it would have come into existence during an era known as the cosmic inflation when space was expanding very quickly. This expansion is believed to lead to the introduction of certain types of particles called scalars such as the Higgs boson.

Wait what?

The inflationary epoch lasted from 10−36 seconds after the conjectured Big Bang singularity to some time between 10−33 and 10−32 seconds after the singularity.

That's what I thought.

[Painboy]

Who cares about Dark Matter when you can find gold

Detecting particles that aren't dark matter is unwanted noise to SABRE—which is why they located the experiment one kilometre down a mineshaft, where the rock above was thought thick enough to absorb any cosmic radiation.

However, the team found some radiation still penetrated—not ideal for isolating rare dark matter events, but creating a powerful source of information. "Nature has given us the most powerful penetrating scanner you can create, and there's no licence required," said Duffy.

These particles that make it to the Stawell Underground Physics Laboratory are muons: short-lived particles similar to electrons, but 200 times heavier. Muons are preferentially scattered by atoms with high atomic numbers and so deposits of heavy metals, such as gold, whose atomic number is six times greater than that of carbon, create shadows similar to bones in a medical X-ray image.

The idea's not entirely new, but Duffy noted that the technology "had come of age." The team's redesigned muon detector prototype is a far cry from its 1960s predecessor, a box of bulky high-voltage electronics that needed two people to lift it. Miniaturisation of electronic components driven by smartphone technology contributed to Duffy's device, which he likens in size to "a fashionable paperweight."

[thoreau]

A similar concept has been used in archaelogy. If you aren't sure whether that pyramid has hidden chambers, put a muon detector in there and see if you get more muon transmission along certain pathways (i.e. directions that would have them passing through the region of the hidden chamber).

From a fundamental physics perspective, muons are thoroughly unnecessary, but they exist nonetheless. I forgive them for existing because they help us teach relativity (they make for great problems in relativity homework) and help archaeologists search for hidden chambers. Not as useful as a bullwhip when you need to explore ancient ruins, but still useful.

[Andrew]

A relative with a PhD in some sort of geology used to do gold prospecting for mining companies using a detector I never got too many details about. I wonder if it was something similar.

[Kolohe]

New Study Reveals Dark Matter May Have Predated the Big Bang

Ow, my brain!

The novel study employs a simple mathematical framework to illustrate that dark matter may have been produced before the Big Bang. More specifically, it would have come into existence during an era known as the cosmic inflation when space was expanding very quickly. This expansion is believed to lead to the introduction of certain types of particles called scalars such as the Higgs boson.

Wait what?

The inflationary epoch lasted from 10−36 seconds after the conjectured Big Bang singularity to some time between 10−33 and 10−32 seconds after the singularity.

That's what I thought.

Hey, yeah Doktor T can you explain this - https://journals.aps.org/prl/abstract/1 ... 123.061302

Dark matter (DM) may have its origin in a pre-big-bang epoch, the cosmic inflation.

Is this sloppy writing, or different use of terms between the lay and professional audiences? I mean, JHU isn't a charm school.

[thoreau]

As best as I can make out, they're using the term "Inflation" to mean "The First 10^-32 seconds" and "Big Bang" to mean "The next few seconds after that."

But this is not my field, in any sense of the word.

[Aresen]

As best as I can make out, they're using the term "Inflation" to mean "The First 10^-32 seconds" and "Big Bang" to mean "The next few seconds after that."

But this is not my field, in any sense of the word.

And that's what confused the hell out of me about the story, since I always thought of the 'Big Bang'* as including the inflationary epoch.

*Preferred terminology: "The Horrendous Space Kablooie"

[thoreau]

As best as I can make out, they're using the term "Inflation" to mean "The First 10^-32 seconds" and "Big Bang" to mean "The next few seconds after that."

But this is not my field, in any sense of the word.

And that's what confused the hell out of me about the story, since I always thought of the 'Big Bang'* as including the inflationary epoch.

*Preferred terminology: "The Horrendous Space Kablooie"

I think the idea is that the mechanisms in play during the inflationary epoch are so different from what was happening subsequently that it's almost like a completely separate thing.

Also, by using terminology that confuses non-experts, they can get more publicity. "A universe BEFORE the universe!"

[Kolohe]

Ok thanks. I always understood "Big Bang" as t=0, though with an open circle on the timeline.

[JD]

Chemists discover water microdroplets spontaneously produce hydrogen peroxide

To find out, Zare, Walker, staff scientist Jae Kyoo Lee and colleagues conducted a series of tests, the simplest of which involved spraying ostensibly pure water microdroplets onto a surface treated so that it would turn blue in the presence of hydrogen peroxide—and turn blue it did. Additional tests confirmed that water microdroplets spontaneously form hydrogen peroxide, that smaller microdroplets produced higher concentrations of the molecule, and that hydrogen peroxide was not lost when the microdroplets recombined into bulk water.

[JD]

If you're familiar with Robot Chicken, just imagine the nerd who exclaims "SO COOL!"; that's basically me right now:

NASA is sending a helicopter to Mars. It'll be the first aircraft to fly on another planet

That said, I'm almost surprised they didn't opt for some kind of lighter-than-air vehicle, but I guess Mars' atmosphere being about 1% as dense as Earth's cuts both ways. (There have been some thoughts about hot air Mars balloons, though.) As it is, the helicopter scout will have blades about 1m in diameter to lift a 1.8kg body.

[Jadagul]

If you're familiar with Robot Chicken, just imagine the nerd who exclaims "SO COOL!"; that's basically me right now:

NASA is sending a helicopter to Mars. It'll be the first aircraft to fly on another planet

That said, I'm almost surprised they didn't opt for some kind of lighter-than-air vehicle, but I guess Mars' atmosphere being about 1% as dense as Earth's cuts both ways. (There have been some thoughts about hot air Mars balloons, though.) As it is, the helicopter scout will have blades about 1m in diameter to lift a 1.8kg body.

I think one of the summer research students I secondarily-advised was working on that this summer.

[Warren]

If you're familiar with Robot Chicken, just imagine the nerd who exclaims "SO COOL!"; that's basically me right now:

NASA is sending a helicopter to Mars. It'll be the first aircraft to fly on another planet

That said, I'm almost surprised they didn't opt for some kind of lighter-than-air vehicle, but I guess Mars' atmosphere being about 1% as dense as Earth's cuts both ways. (There have been some thoughts about hot air Mars balloons, though.) As it is, the helicopter scout will have blades about 1m in diameter to lift a 1.8kg body.

How does it cut the other way? 1m blades to lift 1.8kg in the Martian atmosphere? I can't believe it. Solar powered no less? I'd have bet significant sums such a thing was not possible.

[Aresen]

If you're familiar with Robot Chicken, just imagine the nerd who exclaims "SO COOL!"; that's basically me right now:

NASA is sending a helicopter to Mars. It'll be the first aircraft to fly on another planet

That said, I'm almost surprised they didn't opt for some kind of lighter-than-air vehicle, but I guess Mars' atmosphere being about 1% as dense as Earth's cuts both ways. (There have been some thoughts about hot air Mars balloons, though.) As it is, the helicopter scout will have blades about 1m in diameter to lift a 1.8kg body.

How does it cut the other way? 1m blades to lift 1.8kg in the Martian atmosphere? I can't believe it. Solar powered no less? I'd have bet significant sums such a thing was not possible.

I think Thunderf00t did a video on it. IIRC, the blade width, attack angle and the rotation speed are sufficient to generate enough lift in the lower Martian gravity. Also, the range is quite limited ( < 1 km) and it takes most of a Martian 'sol' to store the power for a single flight.

[Kolohe]

If you're familiar with Robot Chicken, just imagine the nerd who exclaims "SO COOL!"; that's basically me right now:

NASA is sending a helicopter to Mars. It'll be the first aircraft to fly on another planet

That said, I'm almost surprised they didn't opt for some kind of lighter-than-air vehicle, but I guess Mars' atmosphere being about 1% as dense as Earth's cuts both ways. (There have been some thoughts about hot air Mars balloons, though.) As it is, the helicopter scout will have blades about 1m in diameter to lift a 1.8kg body.

How does it cut the other way? 1m blades to lift 1.8kg in the Martian atmosphere? I can't believe it. Solar powered no less? I'd have bet significant sums such a thing was not possible.

Cuts both ways in that when your 'air' pressure is 4 to 5 Torr, you don't have much room to go 'lighter than air'

[Warren]

If you're familiar with Robot Chicken, just imagine the nerd who exclaims "SO COOL!"; that's basically me right now:

NASA is sending a helicopter to Mars. It'll be the first aircraft to fly on another planet

That said, I'm almost surprised they didn't opt for some kind of lighter-than-air vehicle, but I guess Mars' atmosphere being about 1% as dense as Earth's cuts both ways. (There have been some thoughts about hot air Mars balloons, though.) As it is, the helicopter scout will have blades about 1m in diameter to lift a 1.8kg body.

How does it cut the other way? 1m blades to lift 1.8kg in the Martian atmosphere? I can't believe it. Solar powered no less? I'd have bet significant sums such a thing was not possible.

Cuts both ways in that when your 'air' pressure is 4 to 5 Torr, you don't have much room to go 'lighter than air'

That's still cutting the same way. Less atmosphere makes it harder to fly by pushing against the atmosphere or being buoyant.

[Kolohe]

That is exactly what JD meant. (I'm reasonably sure)

[Jadagul]

"The atmosphere is thin, so it will be hard to engage in powered flight, so we should do lighter-than-air flight" cuts in the opposite direction from "The atmosphere is thin, so it will be hard to engage in lighter-than-air flight, so we should do powered flight."

[Warren]

"The atmosphere is thin, so it will be hard to engage in powered flight, so we should do lighter-than-air flight" cuts in the opposite direction from "The atmosphere is thin, so it will be hard to engage in lighter-than-air flight, so we should do powered flight."

The atmosphere is thin so it will be hard to do either. We should do rockets and jumping.

[JD]

That is exactly what JD meant. (I'm reasonably sure)

That is indeed what I meant. I think everybody agrees, we may just be interpreting things slightly differently.

[JD]

Yaghi, a chemist at the University of California, Berkeley, reported that he and his colleagues have created a solar-powered device that could provide water for millions in water-stressed regions. At its heart is a porous crystalline material, known as a metal-organic framework (MOF), that acts like a sponge: It sucks water vapor out of air, even in the desert, and then releases it as liquid water.
...
Farha’s team reported in the 26 March issue of Angewandte Chemie that a MOF-caged enzyme called formate dehydrogenase can convert CO2 to formic acid, a common industrial chemical, at more than three times the rate of the uncaged enzyme, and under greener conditions than formic acid is normally made. At the meeting, Thomas Rayder, a graduate student at Boston College, reported building on the idea. He encapsulated a pair of enzymelike catalysts in a zirconium-based MOF to drive a series of reactions that convert gaseous CO2 to methanol, a liquid fuel.

https://www.sciencemag.org/news/2019/09 ... iquid-fuel