Science Questions

[Darkflame]

I think the strikes are still producing wayyyy more then we are generating ourselves though no?
The question would be how quickly they spread out vs the size/efficiency of your "magic tech" collection mechanism.
I think the main issue would be if your in geo-sycn orbit fixed above something your very very high up, so it would probably spread out far too much by the time it gets to you.

hmm....Maybe better to hope for that EM Drive thing turning out to be something to get around mass/energy trade offs of space propulsion.

[Darkflame]

Anyway...my question;

Recently we had some solar panels installed on our house, seem to be working ok so far. At current rates should pay for themselves in about 7 years.
Obviously it generates mostly proportionately to sunlight striking on it. Nicely we can get a graph of its power generation each day.

Last few days its been particularly sunny, and I noticed an odd pattern;



We tend to get almost a straight line upto mid day, and then an inconsistent spiky curve past that point.
The initial jump you see at 10:00 I am 90% sure is the show of next doors roof no longer casting on some of the cells.

However, the overall shape I find puzzling. It just seems too straight to be natural upto midday. I expected a bell-curve.

Any hypothesis?

[mariomario42]

I'd say the graph is a very similar shape to the irradiance, as seen below. Of course taking in account of scaling.



and this is the shape of ideal equation based.

[Metcarfre]

"a few days" isn't enough to make a conclusion from I'd say. Could be intermittent clouds, faulty readings, intermittent shade, etc.

[Dutch guy]

From that pattern and the timing I'd guess clouds. Thermal activity (rising warm air convection causing cumulus clouds to form) usually starts between 12:00 and 13:00, so intermittent clouds could be covering the panels in shadow.

[Smeghead]

Question: How would our signals (radio etc) be recieved out in deep space? For example a spacecraft picking up our first radiosignals from the early 20th century: would one be able to pick up full broadcasts from the distant past or would the somehow be garbeled somehow?

[AdmiralMemo]

If there's nothing in the way like a nebula or something, they should be able to pick up full broadcasts, in theory. They would not be garbled.

However, since the broadcasts are undirected, they're going out in a sphere. Thus, the transmissions are going out at the same power, but the area that they're covering is increasing at a rate of 4πr², with r being light-time-unit per time-unit. I highly suspect that even at the nearest stars, you'd need a very powerful antenna to pick up a very faint signal.

Proxima Centauri is the closest star, and is about 4.25 light years away. If you sent out a basic signal today, then, 4.25 years from now when it reaches Proxima Centauri, the area the signal is reaching is going to be about 226.25 square light-years. Due to the inverse-square law, this will be significantly decreased power per area. Earth's surface is 5.101 X 10^8 km². The surface area of the sphere of radio signals when it reaches Proxima Centauri is 2.025 X 10^28 km². Since that's 20 orders of magnitude, you're talking a signal roughly 250 quintillion times fainter at Proxima Centauri than it was on Earth.

So... The signal won't be garbled, but it will likely be swamped by local transmissions from natural sources by the time it reaches any place significant.

[Smeghead]

aw, bugger.
The idea I had required it to be about 250(ich) light-years away, but by then I doubt anything could be picked up

[Darkflame]

Directed blasts can be further;
http://en.wikipedia.org/wiki/Arecibo_message

If we find planets that look like they might have life,and they are in a few hundred light years, with difficulty but possible, we could send messages there and hope they are listening. Stray radio almost certainly wouldnt be good enough. - which is fortunate, as it means they wont be getting that embarrassing Hitler transmission we sent.....



(weirdly, I thought I replied hear earlier not getting back to people about the solar datA odd. Basicly I have to wait longer to get a better sample range, as the severs were down for a bit, and then bad weather)

[AdmiralMemo]

A sphere of 7.03x10^31 km² would be about 250 light years away. The signal would be about 1.37x10^23 times as faint.

As Darkflame said, that's only for background radio/TV/etc. signals that aren't directed. I'm assuming the idea was the aliens picking up stray signals that weren't specifically meant for them.

Decreasing the area of the transmission increases the power significantly. Laser-blast a message at a star and it'll probably be received pretty clearly if it's within this galaxy. But... For that to happen, we have to be specifically directing the message somewhere, and hope that the spot we're sending to has something capable of receiving it.

Also, due to atmospheric concerns, AM radio is pretty much hosed and not going out into space at all.

However, if it helps, if your story about aliens depends on just picking up a signal in general, and not a specific signal, there may be hope. Even at those ranges, because we're sending out all sorts of signals on tens of thousands of different frequencies from tens of thousands of transmitters simultaneously for a nearly constant time, the total volume of Earth's EM radiation from all the transmissions collectively might be detectable. If they were pointing at the right star at the right time and had sensitive enough equipment, the aliens might be able to detect that the radiation is not likely coming from a natural source.

[Smeghead]

Well the idea was of a human ship who's FTL drive is broken thus stranding them in deep space and as a minor side story they would pick up old signals from earth's past (mostly just to show just how far out they are but also to be a kind of reminder of the home they left behind and can never return to), and sadly I can't see any reason for them having some kind of super receiver that could pick up signals that weak.

[Dutch guy]

Well the idea was of a human ship who's FTL drive is broken thus stranding them in deep space and as a minor side story they would pick up old signals from earth's past (mostly just to show just how far out they are but also to be a kind of reminder of the home they left behind and can never return to), and sadly I can't see any reason for them having some kind of super receiver that could pick up signals that weak.

On the other hand, it IS science fiction so just making them able to receive signals because reasons is not impossible. Throw in a little explanation like lensing effects from a black hole somewhere and you'd be good for most readers.

[Smeghead]

I guess, but I don't know. I always try to root as much of things in actual science (which is why I'm asking so many questions in here every time an idea strikes me), and from a story point it doesn't make sense that they would have such a thing. Mostly because the people meant to be listening to said signals might not have access to the resources and equipment that is part of the ship, but rather something smaller.

[Lord Chrusher]

Other stars are long, long way away but radio telescopes are quite sensitive so in principle you do have a slight chance of detecting radio waves from Earth at the distance of the closest stars using existing technology if not for the Sun. While the Sun is relatively faint at radio wavelengths (at low frequencies the Sun is fainter than the Milky Way), the Sun would be brighter than the signals you would be trying to detect.

[Smeghead]

I should write this idea down and have you people who are way better at science and math then me look over the basics things, because I'd hate to have developed it a long way along only to suddenly realize that I got something fundamentally wrong.

EDIT: I did
http://thesmeggyone.tumblr.com/private/101334741112/tumblr_ne9ce8hQzo1s5nhmr

[Metcarfre]

You're already handwaving with the FTL drive, so I don't see why receiving signals is such a problem.

You'll have to consider how far away the target systems are for a reasonable account of what era of signal she recieves (considering it's the 23rd century).

As a side note, I think it might be more interesting to explore a serious of short stories from various perspectives on the whole timeline rather than focus on one set-adrift-after-damage-to-stasis-pod-survivor (quite a well-tread trope).

[Smeghead]

Well I went with the FTL drive because it might be "theoretically" possible to exist, and the alternative would be that the journeys would take thousands of years and that kind of writes off having a living crew.
And yeah the pod survivor is kind of only really the backdrop; a introduction really while she will play a role later, several parts of the story are basically short stories about the events leading up to their current predicament as seen from the eyes of people who were there to see it (amongst the crew, given that people live much longer because of medical advancements and genetic modifications there were some in the crew who were alive to see the first human FTL journey and can remember the events that followed).
That is because there is no day to day threats they might face like aliens or major shortages in food/water etc; if there is a doom coming to them it doesn't seem to be coming fast or in a obvious way.
That said there are things going on like threats of revolt amongst the crew (especially amongst those born on the ship and who have never seen earth), a serial killer who goes unnoticed, a "ghost in the machine" and several other things but that might not be a immediate threat, giving time for a lot of short stories.

[Darkflame]

"Well I went with the FTL drive because it might be "theoretically" possible to exist, and the alternative would be that the journeys would take thousands of years and that kind of writes off having a living crew."

Not quite.
If you can go at, say, 95% of C, you get some time dilation working (sort-of) in your favor. The crew would age at a much slower rate then the rest of the universe.
The 4 years it takes to visit say, Alpha Proxima at C, from earth is only earth-time. For the light itself it takes essentially no time at all.

This has a downside though;
Everyone you knew back home would be long dead.
In fact, unless your speeds are sycned, any near C travel you can probably forget about seeing loved ones again.
(you could always have a society where people do "laps around the sun" or something to stay in sycned with family aboard far traveling ships...I think that would work if its an issue)
==
That all said; Nothing wrong with having FTL drives, Hyperdrives,Starburst,Warp or any other "magic" solution.
As long as you establish the rules of your universe and stick to it thats more important then correlating with our current knowledge of physics.

[Smeghead]

I went with the Alcubierre drive since it is one that doesn't "really" go faster then the speed of light as much as exploits a loophole in the laws of physics by bending space around it (I don't know if living in a bubble in space-time going 10 times the speed of light would affect aging), and because it is one that is talked about as being "theoretically" possible by science today, although heavy emphasis is put on the quotation marks there.
Besides in this case it wouldn't matter if there was no one left back home (on earth) since they would all have died from the planet being toasted anyway).

Also I don't think anti-matter is powerful enough to power a drive like that anyway (also getting that much anti-matter is really damn hard) but this is where I give the fiction some boost and say that these things will be sorted in the next 200 years or so, I mean while I try to keep it as close to science as possible, some liberties has to be taken. That said I would like to be made aware of the problems so that I might look into maybe finding a more scientifically sound alternative if one exists.

Also i was under the impression that the speed of light wasn't what would make people experience time differently then people who didn't as much as it is gravity messing with our perception of time. If I recall GPS satellites experiences time slightly faster then us due to them experiencing slightly less gravity then us (thus having to be calibrated often in order to stop guiding people into fields).
In Stephen Hawking's TV series on the universe he mentioned that a ship circling a super-massive black hole would experience time at half the rate as we on earth would

[Darkflame]

Both gravity and speed effect time, your correct. I am not sure which has the greater effect - but going at C exactly does mean your frozen relative to people still. (or, from your perspective, the rest of the universe pass's instantly).

I would guess with GPS they have to correct for both as the satellites are both high up, traveling very very fast and the accuracy has a to be stunning. (as triangulation is done by time-of-flight on the radio signals that themselves travel at or near C).
--

Regarding antimatter fuel; You probably want to work out how its stored as thats just as tricky as making it.
To my knowledge is still the best candidate for long term fuel though as (again to my knowledge) its got the highest energy density.

The only other possibility is if the EMDrive turns out real;
http://en.wikipedia.org/wiki/EmDrive
Then you could have everything run of solar. (very slow acceleration, but great top speeds as it could run constantly without fear of wasting fuel).

It sounds like your going in the right direction already though

[Lord Chrusher]

For science fiction, try to be as self consistent as possible and be very careful with technobabble.

[Smeghead]

Don't worry because I HATE technobabble; one of the reasons why I never watched Star Trek

[Darkflame]

Star Treks not as bad as its rep. TNG s1 / 2 had it bad, but they toned it down considerably after that. Hardly any Multimodal reflection sorting.
Meanwhile TOS didn't have much at all, it was more concerned with Kirk fighting space gods with his shirt off and DS9 stuck mostly to political stuff...and space gods.

[Elomin Sha]

And Voyager had to deal with decanonised Warp 10 lizards that mutated from two crew members, mated then went back to normal with no issues.

[Darkflame]

And Voyager had to deal with decanonised Warp 10 lizards that mutated from two crew members, mated then went back to normal with no issues.

Which we assume happened in the same universe as "Spocks Brain", and no where near the real trek universe. AT ALL.