1

Physics, Astronomy & Cosmology / Re: If Andromeda is red shifted how can we collide with it?

« on: 28/01/2024 20:36:35 »

Ah, ok, well thanks for that.  I have to blame chat gpt for the information.

Chat bots are designed to chat realistically, speaking factually is irrelevant.

2

General Science / Re: What Is Gray?

« on: 16/01/2024 10:19:56 »

What is white? If you shine an intense enough light on grey does it become white?

It becomes whiter.  "White" is very much a matter of perception, which is why detergent manufacturers include blue specks in their product to modify the spectrum emitted from nominally white materials.

3

General Science / Re: What Is Gray?

« on: 15/01/2024 11:42:53 »

.....it does not prevent damage to the head and neck. Military transports have the passenger seats facing backwards - much, much safer.   

Not that seat belts make much difference in civil aviation. Many people unbuckle them as soon as the wheels touch the ground, that is, when entering the phase of the journey most likely to incur sudden braking or collision. There's a lot of air upstairs, and very few aircraft, mostly 5 miles apart, but taxiways are narrow and occupied by all sorts of traffic.

It's a known fact that your IQ drops by 10 points whenever you sit in the pilot's seat, but the behavior of passengers, particularly on budget airlines,  is utterly baffling.  Your ticket says "one carry-on bag", but at least 20% of passengers are unable to count up to 1. Why do people stand in a queue for an hour before boarding, if they have assigned seats? Why do they pay for "priority boarding", which means waiting in another queue at the bottom of the stairs? Why do they stand up as soon as the plane stops moving, fight to encumber themselves with their precious one bag, then hang around in the aisle waiting for the doors to open? 

4

General Science / Re: What Is Gray?

« on: 13/01/2024 21:43:31 »

Looks very much like my favorite tourist map of Australia. There's a green strip round the edge marked "sharks, octopuses,  spiders, snakes and poisonous toads" and a red blob in the middle marked "nothing".

5

Chemistry / Re: Ammonium perchlorate

« on: 09/01/2024 10:10:13 »

Is it Toxic &/Or Explosive?

https://en.wikipedia.org/wiki/PEPCON_disaster

6

New Theories / Re: An essay in futility, too long to read :)

« on: 17/11/2022 12:48:19 »

And the next step from 'recycling' is where they press governments to move the costs from their behaviors to the taxpayers.

7

Technology / Re: Does wi-fi harm the environment?

« on: 17/10/2022 21:49:23 »

How bad is wi-fi to the environment?

Compared to what?

Rather than flying 1,000km (each way) to visit a customer in the next city, it is far better for the environment (and my time, and the cost to my employer and ultimately the public) for me to do a videoconference over WiFi.

Of course, only the first and last couple of meters of that videoconference are carried over WiFi.
-  I assume that you mean telecommunications in general
- The mobile phone in your pocket only uses WiFi while it is in the house. Once you get outside it switches to a cellular mobile network - similar technology, but on different frequencies (and financed differently).
- There is increasing interest in using satellites in Low Earth Orbit (LEO) to provide data and other communication services to people living in remote areas, plus planes and ships

In general, to send a signal farther, you need more power.
- Sending data 2 - 10 meters to a WiFi hotspot in your house uses very little energy
- Sending the same data 100-1000 meters to a cell tower takes more power
- Sending the same data 400km to an orbiting satellite takes even more power, and a much larger antenna at both ends
- That's why most data today is transmitted most of the way via optical fibers - the refractive index of the fiber redirects the laser beam into the core of the fiber, so that the signal is confined, and it travels farther with less loss and interference than wireless systems.
- Optical fibers are better for many purposes than wireless - except for the last couple of meters to where you are now. You don't want to be tethered to an optical fiber all day!

Electronics requires mining various minerals - but so does making a car or a home. The electronics in your pocket has advanced by a factor of a million in the past 40 years, and is far more environmentally friendly than the same functionality back then (as well as being thousands of times cheaper).

In contrast, cars and houses have improved their environmental credentials a bit - but at best by a factor of 2.

should we not be putting mobile phones in our pockets?

The signal levels put our by mobile phones are milliWatts for WiFi, and closer to a Watt for cellular mobile when you are far from the base station. Satellite communication takes even more.
- But all of this is negligible compared to the intense radiation from the Sun every time you walk outside.

Overall, I suggest that (where possible), rather than commuting an hour each way to work, you work from home (over WiFi), and at lunchtime you take your mobile phone with you, and go outside for a walk in the Sun - that is good for you and the environment.

8

General Science / Re: How cold does the planet have to get for the oceans to freeze?

« on: 15/10/2022 11:48:39 »

I have worked on their design and instrumentation but have no stock at present.

9

General Science / Re: What should we do with radioactive waste from the nuclear power industry ?

« on: 07/10/2022 09:14:29 »

Actually Im a little worried about this war because you never know what will happen if they reach Cernobyl

Perhaps you should look at what happened when they did earlier this year

10

Plant Sciences, Zoology & Evolution / Re: Could a chicken fly?

« on: 22/09/2022 19:02:27 »

I have seen dead chickens fly at several hundred kilometres/hour. Bird strike tests on turbofan engines. This proves "chickens can fly"!

11

Plant Sciences, Zoology & Evolution / Re: Could a chicken fly?

« on: 22/09/2022 13:13:40 »

Stole from the web...
An industrious turkey farmer was always experimenting with breeding to perfect a better turkey.

His family was fond of the leg portion for dinner and there were never enough legs for everyone. After many frustrating attempts, the farmer was relating the results of his efforts to his friends at the general store get together. "Well I finally did it! I bred a turkey that has 6 legs!"

They all asked the farmer how it tasted.

"I Don't know" said the farmer. "I never could catch the darn thing!"

12

Plant Sciences, Zoology & Evolution / Re: Could a chicken fly?

« on: 21/09/2022 17:20:55 »

They dont fly freely.

Mine did, just not very far.

The natural "ur-chicken" is a social, forest-dwelling bird. Living in a flock, and being well insulated, it has no need to fly very far: they don't migrate,  mammalian predators can't fly at all, large avian raptors avoid dense forests, and small raptors (even dogs!) avoid fighting with cockerels. But it does need to sleep off the ground and to take off quickly if attacked by a mammal. So it has evolved to fill an ecological niche.

The domestic chicken is an odd creature in many ways. Most birds lay eggs once or twice a year in a distinct nest and sit on them until they hatch but the free-range  farmyard chook lays an egg every day, not always in the same place, and  only gets truly "broody" and sits on her eggs  once or twice in a lifetime. That said, the bird has been bred to have very large flight muscles (the white bit) and carries very little dead weight (leg bone), so is still capable of rapid takeoff in any direction, even by running downwind (unlike soaring birds).

Horses for courses.   

13

Plant Sciences, Zoology & Evolution / Re: Could a chicken fly?

« on: 20/09/2022 21:24:01 »

So, we can add chickens to the list of things you don't know much about.
https://www.raising-happy-chickens.com/can-chickens-fly.html#:~:text=They%20use%20their%20wings%20to,happily%20in%20a%20tree%20nearby.

14

Technology / Re: Shower Chairs

« on: 14/09/2022 00:38:49 »

Because if you aren't very stable on your feet at the best of times, adding a slippery floor is a recipe for disaster!
- Osteoporosis (weak bones) is common in older people, and in people who don't get enough exercise
- A broken hip is a common trigger for people to move from independent living into a nursing home
- And months of confinement to bed only causes weaker bones - leading to a downward spiral

On the other hand, being seated frees up your hands for showering, instead of supporting yourself (eg on a Zimmer frame).

15

Physics, Astronomy & Cosmology / Re: Why is aircraft destruction via lightning extremely-extremely rare?

« on: 04/09/2022 10:25:26 »

Many thanks! Old wisdom among fliers:

After 100 hours, you know everything
After 1000 hours you realise you don't know everything
After 10,000 hours you know you will never know everything

16

Physics, Astronomy & Cosmology / Re: Why do people science-people insist that Venus has the hottest surface?

« on: 28/08/2022 17:28:40 »

The 'surface' is where the atmosphere ends, not necessarily where the solid starts.

That's not well-defined for a gas giant, though. As you go deeper into the atmosphere, the pressure and temperature increases until you go from a gas to a supercritical fluid (which has characteristics intermediate between that of a gas and a liquid).

17

Physics, Astronomy & Cosmology / Re: Why is aircraft destruction via lightening extremely-extremely rare?

« on: 27/08/2022 15:03:12 »

It's a common occurrence at intermediate altitudes (generally below 10,000 ft) and  can be a bit of a bugger but all the metal bits of the airframe are carefully bonded together so that the machine is effectively a Faraday cage with no potential difference between the parts. Radio and radar aerials that project through the shell are protected by discharge tubes or semiconductor shunts.

The real problem is the attendant turbulence, which can indeed destroy an airframe or distort it into an unflyable state, and violent "downbursts" of descending air and precipitation that can push you into the trees on approach (there's no excuse for taking off in a thunderstorm, but what goes up must come down). Rapid icing and hail damage in and around cumulonimbus should be survivable if it's not avoidable, but there are limits to what can be done or avoided by any particular aircraft, and no limits to what nature can throw at you.

I recall being struck twice on approach to Dublin. Lots of noise and shaking for a fraction of a second, but the real problem was landing on 2 inches of hailstones.

A friend got sucked into a cu-nim in a glider which rapidly disintegrated. He extricated himself from the still-rising wreckage and had the presence of mind not to open his parachute until he fell out of the cloud. He now wears a little gold caterpillar lapel badge, the emblem of parachute survivors. 

18

Physiology & Medicine / Re: Why has no Warp Speed Pill been invented to Stop Periods?

« on: 04/08/2022 21:24:32 »

A very few men are  so sexually insecure and socially inadequate that they feel a need or even a right to assault women. These are the people who need medical treatment, not all women.

19

Just Chat! / Re: Do British pubs typically serve restaurant quality food?

« on: 04/08/2022 17:56:01 »

There has been a massive change in my lifetime, following tighter drink-driving legislation. In my youth, pub food was a grudging addition to encourage lunchtime drinking. With decreasing consumption of alcohol, and increasing competition from supermarkets, the majority of pubs have at least increased the scale and variety of their offerings and a good many are now really restaurants with decent draught beer and a dartboard. My chef son produces Michelin-star food in pubs.

20

Physiology & Medicine / Re: Why has no Warp Speed Pill been invented to Stop Periods?

« on: 04/08/2022 17:36:12 »

Anyone with a brain would be in favor of reducing the population. The means to do so safely and cheaply has been around since 1960. As BC says, how you use it is a matter of choice, unless you subscribe to some bizarre superstition that allows dirty old men to determine your sex life and reproduction.