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Why is it Dark at Night (or, Why ISN'T it Dark at Night)?

SWBStX says...

>> ^messenger:

Because the light has shifted from visible through infrared to microwave due to the expansion of the universe since the Big Bang, 1100 times stretched, according to RFlag's link starting at around 3:11.>> ^SWBStX:
So maybe I'm missing something obvious that should answer this question but I'll ask it anyway. So if the night sky should be light everywhere we look, and the reason it isn't is because it's outside our visible spectrum, why do the pictures taken using an infrared camera still show darkness behind the stars it can see? Why isn't the CBR showing up brightly on the infrared pictures?



Ah, clearly I should have checked out that link. Thanks! Time for a microwave camera!

Why is it Dark at Night (or, Why ISN'T it Dark at Night)?

messenger says...

Because the light has shifted from visible through infrared to microwave due to the expansion of the universe since the Big Bang, 1100 times stretched, according to RFlag's link starting at around 3:11.>> ^SWBStX:

So maybe I'm missing something obvious that should answer this question but I'll ask it anyway. So if the night sky should be light everywhere we look, and the reason it isn't is because it's outside our visible spectrum, why do the pictures taken using an infrared camera still show darkness behind the stars it can see? Why isn't the CBR showing up brightly on the infrared pictures?

Why is it Dark at Night (or, Why ISN'T it Dark at Night)?

messenger says...

He doesn't say that CBR is only far away. He says that if you look in the space between the stars, there's still light, even there. That's to say, only the CBR exists in those directions, and only CBR light comes in from that distance away. The wording could have been better for people who don't know this, as it could sound like it's a ring of light that doesn't come to us, as opposed to light that does come to us, but so shifted that we can only see it with microwave telescopes.>> ^GeeSussFreeK:

Covers a lot here, just to clarify (and he most certainly knows this) that the cosmic background radiation is everywhere...not just far away. He probably meant that, but it isn't what he seems to say towards the summery at the end. That is, of course, is if my understanding of the CMBR is correct. Anyone care to clarify further?

Quick and Simple Life Hacks in the Kitchen

Sorry for being a Dick About the Mars Rover (Sift Talk Post)

ant says...

>> ^Fletch:

EDIT: Ugh... my meds must make me pretentious. Starting over...
Anyhoo, you weren't being a dick. Just blown away by the complexity of the landing, as was I. Just an "are you shitting me!?!?" moment after seeing "7 Minutes of Terror". I just didn't think the method they chose was ego-driven, and that it was about the only way it could have been done given the size of the rover and the thinness of the Mars atmosphere. I guess they could have just deployed some wings or something and glided it down. Sort of a "Wings To Fly Rover Onto Final Landing" system.
It was really cool to watch it live, though. Amazing that they are getting such accurate information from so far away. My landline freaks out if I run the microwave. And pictures just minutes after landing? Amazing.


Ditto! I loved that 64x64 pixels thumbnail they got.

Sorry for being a Dick About the Mars Rover (Sift Talk Post)

Fletch says...

EDIT: Ugh... my meds must make me pretentious. Starting over...

Anyhoo, you weren't being a dick. Just blown away by the complexity of the landing, as was I. Just an "are you shitting me!?!?" moment after seeing "7 Minutes of Terror". I just didn't think the method they chose was ego-driven, and that it was about the only way it could have been done given the size of the rover and the thinness of the Mars atmosphere. I guess they could have just deployed some wings or something and glided it down. Sort of a "Wings To Fly Rover Onto Final Landing" system.

It was really cool to watch it live, though. Amazing that they are getting such accurate information from so far away. My landline freaks out if I run the microwave. And pictures just minutes after landing? Amazing.

Self-Freezing Coke

A Really Dumb Invention??

xxovercastxx says...

>> ^spawnflagger:

I like the idea, but didn't he do a simple product search ?
or hell, even the domain itself - http://www.gojo.com/ . It's a brand of hand cleaner (good stuff too) that's been around for years.
I don't see how he isn't infringing on the brand/trademark "gojo", so a lot of legal battles ahead...
Oh, and lastly - cancer. Do you want a high-powered cell phone transmitter next to your brain, or a low powered bluetooth headset?


Trademarks are only supposed to protect against similar products. It would be trademark infringement to make another soap or cleanser and call it Gojo. A shampoo would probably be considered too similar; maybe something cleaning-related like a sponge or scrubbing brush, too. A headband with a suction cup is not in the same market so it shouldn't be in violation.

The microwaves that are emitted by a cell phone are non-ionizing and thus, not linked to cancer. They're in the same carcinogen group (2B) as coffee and pickles.

Toast Will Never Be The Same - Toastieknife

A Really Dumb Invention??

chingalera says...

Gojo?? Trademarked name of a gelatinous hand cleaner-This guys can't be trying to convince people to wear their damn microwave devices that close to their skulls?
Get off the fucking phone, Joe!?

How a Microwave Oven Works

jimnms says...

>> ^mizila:

Safety Note
A little more basic, but don't boil water with a microwave in a smooth glass container without something (a stick in this video) to disrupt the surface. It could superheat the water.
Microwave + Smooth Glass + Undisturbed Water = Steam Bomb


While super heating water in a microwave is possible, you need a very smooth container, water free of impurities and it must be perfectly still while heating as the slightest disturbance can cause flash boiling. Mass produced glass and plastic measuring cups and other containers will always have small defects and if you have a turn table in your microwave and you're using tap water, you'll be fine as the imperfections in the container combined with impurities in tap water and the motion of the turn table will be enough to prevent super heating.

Also, what the guy says around 1:35 isn't true. A microwave doesn't heat the whole mass of the food because the microwaves can't penetrate the entire mass of the food. If what he said were true, you could stick a whole turkey in it and cook it in minutes, but in reality you'll end up with a hot outside and a cold inside.

How a Microwave Oven Works

mizila says...

**Safety Note**

A little more basic, but don't boil water with a microwave in a smooth glass container without something (a stick in this video) to disrupt the surface. It could superheat the water.

Microwave + Smooth Glass + Undisturbed Water = Steam Bomb

How a Microwave Oven Works

Reefie says...

When a microwave oven breaks it's typically one of 3 things, all of which are quite cheap to repair:
1: magnetron fuse has blown. These fuses range from 500mA up to 1700mA depending on the type of microwaves I've encountered. Typically overpriced, these fuses often sell for upwards of 15 quid despite costing as little as 50 pence from distributors.
2: wave guide cover has been burned through due to arcing of the microwaves. These wave guide covers (or shields) can be replaced by cutting a piece of sheet mica to size using the old wave guide cover as a template. Manufacturers' own replacement covers can often cost around 20 quid.
3: Door sensor is broken, probably from shutting the door too harshly, repeatedly. Considering these things are typically no more complex than a switch that is pressed when the door is closed, manufacturers love to go out of their way to make them look as complex as possible, and therefore drive up prices of spares that are just glorified on/off switches. Usually I recommend buying the manufacturer's own part as a replacement, but on occasion I've helped friends by doing a low-cost repair using a cheap switch from Maplin.

If you took the time to read this I hope you found it useful; if I bored you I'm sorry but I don't know how to give you those 60 seconds of your life back

How a Microwave Oven Works

messenger says...

**Fun Note**

If you put a lightbulb in a glass of water such that the metal screw bit is underwater (it will mostly float above the water) and put it in a microwave, the light will come on.

How a Microwave Oven Works

Boise_Lib says...

**Safety Note**

If you take apart a microwave oven be very, very careful of the capacitor (looks like a metal can near the magnetron). These caps store an impressive amount of charge and can knock you across the room--even after the oven is unplugged.



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