The official science thread.

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yankeehater said:
The paradox comes from the idea that identical twins should always be the same age. You are right that it actually has nothing to do with the two people being related, it is just eaiser for people to visualize what is going on if the 2 people whose ages they are comparing are the same.
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Well I think Einstein explained it with synchronized clocks? Where does that twin thing come from actually?

Zaptruder said:
I'm already rippin' on ID. Why would you take my quote and requote it for... at best, a shitty attempt at humour?
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Is your post patented or something? Relax.

Wasn't an attempt at humour and I never implied that you were defending ID fyi.
ID doesn't even qualify as a hypothesis, not even close.
 
Mad Max said:
E=mc^2
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Ka-pow! Anti-matter annihilation is some pretty potent stuff, though a good portion of that energy comes out in the form of neutrinos and can't be harnessed for anything.
 
ThoseDeafMutes said:
You experience time differently based on the velocity you move relative to other bodies. To an observer watching your journey through a telescope on earth, going at 0.999 c you will take ~4 years to reach Alpha Centari, since it is 4 lightyears away, but to the man on the rocket, you will take far less than this time, perhaps weeks or days (I haven't crunched the numbers to work out exactly, but you can use equations of relativity to work out precisely).
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Why would it take him weeks or days? Is it because time shortens when travelling at speed of light?

I know relativity is when...

You are standing on a platform waiting for a train and you see two trains past by.
One faster than the other. Both will go past you very fast.

But if you are a passenger on the slower train, you will feel/see that the faster train is only going slowly away from you.

That's relativity right? So when speed of light is thrown in, it changes how time progress?
 
MadraptorMan said:
I don't really understand, is there an explosion? Is it big? How come it isn't happening all the time...opposites attract, right?
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Well, it is happening all the time. It's just that you don't get a whole lot of bang when a few pairs of not-so-massive particles annihilate. You'd need macroscopic chunks of the stuff to cause anything that you or I would recognize as an explosion.

In fact, we actually make positrons for medical use. PET scans get an image by recording the radiation that's released by the aforementioned annihilation.
 
Kyaw said:
Why would it take him weeks or days? Is it because time shortens when travelling at speed of light?

I know relativity is when...

You are standing on a platform waiting for a train and you see two trains past by.
One faster than the other. Both will go past you very fast.

But if you are a passenger on the slower train, you will feel/see that the faster train is only going slowly away from you.

That's relativity right? So when speed of light is thrown in, it changes how time progress?
Click to expand...

Pretty much, the train thing is basic relativity, the problem that arises with light is that it always goes the same absolute speed no matter what, and it doesn't change relative to anything else. Because of the way the equations work out (simple distance= rate*time, for example) you can't change the rate and the distance in the case of light, so you have to adjust time.

EDIT: I just read this stuff for fun, so someone with the background feel free to correct me...
 
Couple of remarks for the OP.

While I agree that religion stuff should stay the hell away from this thread, I don't quite get why you say "there's so many religion OT, why not a science one?"
I mean that would be like saying "there's so many sports threads, why not a gardening one" :p

I don't think a link to pubmed will be useful for anyone. I'd rather suggest this one: http://www.the-scientist.com/ (even though it's not just focused on biology/medicine).
 
Kyaw said:
Why would it take him weeks or days? Is it because time shortens when travelling at speed of light?

I know relativity is when...

You are standing on a platform waiting for a train and you see two trains past by.
One faster than the other. Both will go past you very fast.

But if you are a passenger on the slower train, you will feel/see that the faster train is only going slowly away from you.

That's relativity right? So when speed of light is thrown in, it changes how time progress?
Click to expand...

Length contraction means that when you go faster relative to another object, your length becomes shorter than when you were going slower (you "bunch up", although this effect is negligible a human scales). A similar sort of thing happens with time, the faster you go the slower you experience it.

Keep in mind that this is all "relative" - to the person going at a high speed, it's clock seems to be ticking at the normal speed and everyone else looks like they're going in slow-mo and is compressed. This is because you moving at lightspeed and everybody else being stationary is the same thing as everyone else moving in the opposite direction at lightspeed and you being stationary.
 
Kyaw said:
But no one has ever travelled at the speed of light before... :(
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Yes, but there are other ways to experimentally verify it. Long before relativity existed, in 1887, the Michelson-Morley experiment gave results that support the invariable speed of light / length contraction. Since then we've had many, many far more precise tests, and the outcome has been that Relativity is supported more strongly than ever.

Regarding time dilation specifically, CERN has run tests to verify this experimentally. Obviously they can't make clocks go at the speed of light, but they can whip things up to very high speeds and measure, say, the rate of radioactive decay of very short-lived particles. The stationary group had decayed far more than the motion group, and the faster they make it go the less it has decayed when they stop the experiment.
 
Damn, that's some good evidence.

Also am i correct in saying that there is no such thing as heat?
Just vibrations, movement or hitting of particles, right?
 
Can someone tell me why airplanes/airplane engines don't have an MPG rating even at a certain altitudes. I wonder how much more efficient one engine is compared to another on the same airplane type.
 
Kyaw said:
Damn, that's some good evidence.

Also am i correct in saying that there is no such thing as heat?
Just vibrations, movement or hitting of particles, right?
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The vibration of particles is heat. Heat is the vibration of particles. Not sure why you wouldn't consider that heat :/
 
Speaking of heat, I've got a question about it.

I've been out of school for a while and might phrase this stupidly, or maybe the question itself is stupid, but whatever.

From what I remember, when we attempt to convert energy into a usable form, some of it is lost as heat. So essentially, the heat is the "waste" of the conversion process. With efficiency in mind, I remember asking my teacher if there was any way for them to simply use the heat of the reaction as an energy source itself, and he said no. Is that true? And if so, why?
 
ThoseDeafMutes said:
The vibration of particles is heat. Heat is the vibration of particles. Not sure why you wouldn't consider that heat :/
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I saw it in one of the BBC's Horizon documentaries that heat is not a valid form of energy or something like that... :/
 
ThoseDeafMutes said:
Yes, but there are other ways to experimentally verify it. Long before relativity existed, in 1887, the Michelson-Morley experiment gave results that support the invariable speed of light / length contraction. Since then we've had many, many far more precise tests, and the outcome has been that Relativity is supported more strongly than ever.

Regarding time dilation specifically, CERN has run tests to verify this experimentally. Obviously they can't make clocks go at the speed of light, but they can whip things up to very high speeds and measure, say, the rate of radioactive decay of very short-lived particles. The stationary group had decayed far more than the motion group, and the faster they make it go the less it has decayed when they stop the experiment.
Click to expand...

You also don't need CERN to show time dilation; muons from cosmic rays travel deeper in to the Earth than should be possible only due to their relativistically lengthened decay time.
 
meadowrag said:
Speaking of heat, I've got a question about it.

I've been out of school for a while and might phrase this stupidly, or maybe the question itself is stupid, but whatever.

From what I remember, when we attempt to convert energy into a usable form, some of it is lost as heat. So essentially, the heat is the "waste" of the conversion process. With efficiency in mind, I remember asking my teacher if there was any way for them to simply use the heat of the reaction as an energy source itself, and he said no. Is that true? And if so, why?
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It seems like it would be possible.

The new technology could have major implications for the recovery of waste heat from power plants and automobiles. For example, the heat lost through engine exhausts might be captured by the technology and converted into electricity to augment or replace a vehicle’s electrical and air conditioning systems. It could also be important in the primary generation of electrical power.
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http://www.sciencedaily.com/releases/2001/11/011128173305.htm

...Investors from around the globe have flocked to witness this potential wonder, as its described as being able to use "thermionic energy conversion" to convert excess heat directly to usable, waste-free energy. Additionally, the uses are "nearly endless," as it could be placed on a laptop's processor to render the Li-ion cell completely unnecessary, or strapped onto a fireplace in order to generate electricity for gizmos around the house....
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http://www.engadget.com/2006/11/24/eneco-developing-chip-to-convert-excess-heat-directly-to-energ/
 
There are certainly applications that allow you can use waste heat for something else, but entropy always wins out in the end. The example of using heat from a chemical reaction as a fuel source works precisely because you can never capture all of it for useful work, and whatever work you do with it will have losses to entropy as well.
Vive la heat death of the universe!
 
Orayn said:
1. Currently knee-deep in the stuff for a sophomore-level physics course.

2. Dear goodness no. There are many charlatans who make outlandish claims and try to justify them with a flawed, simplistic notion of how quantum physics work, and they always fail spectacularly. "Quantum" should definitely set off your skeptical radar when you hear it attached to anything that sounds like snake oil, but QM really does work, just not in the ways the hucksters would have you believe.
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Yeah I know, I was joking :D I remember reading in 'the Secret' that the way it works was 'Quantum physics'.. followed by a description that bore no relation to quantum physics whatsoever. Thats why I say 'whenever I hear 'quantum physics' I reach for my revolver because, like as not, it is some woo using it to justify homeopathy or some other such thing.

That said, quantum physics, the real thing, is freaking fascinating. I love theory, even if I doubt I come close to understanding any of it.
 
OttomanScribe said:
That said, quantum physics, the real thing, is freaking fascinating. I love theory, even if I doubt I come close to understanding any of it.
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The model of the Heisenberg uncertainly principle as drawing a rectangle with side lengths of "energy" and "length" on top of a wave function always struck me as mind-blowing, but stupidly intuitive at the same time. Neat stuff.
 
Trent Strong said:
Science is based on inductive reasoning, and induction can't be justified. You lose again, science.
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Damn, I thought we were really onto something with the whole "technology" deal. Oh well, all sources of information are equal and science is just another narrative, after all.
:lol
 
Orayn said:
There are certainly applications that allow you can use waste heat for something else, but entropy always wins out in the end. The example of using heat from a chemical reaction as a fuel source works precisely because you can never capture all of it for useful work, and whatever work you do with it will have losses to entropy as well.
Vive la heat death of the universe!
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Ah ha, this makes sense. Waste is waste in the end. Darn you energy.
 
Grakl said:
Ah ha, this makes sense. Waste is waste in the end. Darn you energy.
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Thermodynamics:

1. You can't win, you can only break even.
2. You can only break even at absolute zero.
3. You can't reach absolute zero.
 
Raist said:
Couple of remarks for the OP.

While I agree that religion stuff should stay the hell away from this thread, I don't quite get why you say "there's so many religion OT, why not a science one?"
I mean that would be like saying "there's so many sports threads, why not a gardening one" :p

I don't think a link to pubmed will be useful for anyone. I'd rather suggest this one: http://www.the-scientist.com/ (even though it's not just focused on biology/medicine).
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Noted.

Bulbo Urethral Baggins said:
I'm not sure I understand your question. So you are spotting your own microarrays, right? And you know the species you are testing for?
Can't you just search genbank and find a consensus sequence among strains for each species and design oligos?
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Maybe I was a bit unclear. Currently, I'm doing Microarrays on 16S rDNA, amplified by PCR from faecal (bacterial) DNA extracts. The oligos I am using now are +/- 20 bp long. Most of the oligo probes I am using are species specific, or they should be at least. They should not cross-react to other species.

However, I am not satisfied with the coverage of my probes. I think we should include more species on the microarray. I have a huge list of species that I would like to probe on the array (Agilent allows costumers to send them your probe sequences and they will spot them on a slide). Now I am looking for a method to design 16S oligos for those species, but it takes way to long. I have ~600 bacterial species to add.

Currently, I use RDP and probeBase.

On a brighter note: I'll be rocking micro-arrays today :)
 
ThoseDeafMutes said:
You experience time differently based on the velocity you move relative to other bodies. To an observer watching your journey through a telescope on earth, going at 0.999 c you will take ~4 years to reach Alpha Centari, since it is 4 lightyears away, but to the man on the rocket, you will take far less than this time, perhaps weeks or days (I haven't crunched the numbers to work out exactly, but you can use equations of relativity to work out precisely).
Click to expand...
Needs to be quoted again since almost every movie or tv program make the mistake of saying a trek to this star would take 4 years from the crew perspective followed by some grim music while a narrator/character says "and millions of years have passed on Earth, everyone they knew is dead...".

This lack of attention always bothered me since I was in school. Hello!? This only would made sense if we got the distances from "talking" photons: "So Mr. Alphari Light, how long took you to get here? Four years! I see, thank you for your report."
 
Youta Mottenai said:
Needs to be quoted again since almost every movie or tv program make the mistake of saying a trek to this star would take 4 years from the crew perspective followed by some grim music while a narrator/character says "and millions of years have passed on Earth, everyone they knew is dead...".

This lack of attention always bothered me since I was in school. Hello!? This only would made sense if we got the distances from "talking" photons: "So Mr. Alphari Light, how long took you to get here? Four years! I see, thank you for your report."
Click to expand...

Actually, at the speed of light, time stops for you. So from a photon's perspective, the trip took no time.
 
ThoseDeafMutes said:
Too bad photons don't actually travel at c then :(

In a medium. Cherenkov radiation <3
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Obviously, I'm talking under ideal conditions. My point is, just like time will contract for the human travellers and take much less than the 4 years experienced on Earth, so it will for the photons which, under ideal conditions, would be traveling at c proper.
 
So... time travel is sort of possible in a way that, you would only be weeks older when everything else is 4 years older when travelling at the speed of light.

We could be stuck on a vehicle going at the speed of light for about 10 years from the passengers' perspective (not from earth) and Earth's technologies would have advanced by thousands of years. We can get off the vehicle and see the future. And in a way live for millions of years. But the side effects and the energy required to do these would be make it near impossible to achieve probably.

Don't know exactly how we can go back in time without me knowing so much about quantum physics.

Please dont bash me for not understanding so much about these stuff, i'm only 16 and i want to learn these things. :)
 
Boozeroony said:
Noted.



Maybe I was a bit unclear. Currently, I'm doing Microarrays on 16S rDNA, amplified by PCR from faecal (bacterial) DNA extracts. The oligos I am using now are +/- 20 bp long. Most of the oligo probes I am using are species specific, or they should be at least. They should not cross-react to other species.

However, I am not satisfied with the coverage of my probes. I think we should include more species on the microarray. I have a huge list of species that I would like to probe on the array (Agilent allows costumers to send them your probe sequences and they will spot them on a slide). Now I am looking for a method to design 16S oligos for those species, but it takes way to long. I have ~600 bacterial species to add.

Currently, I use RDP and probeBase.

On a brighter note: I'll be rocking micro-arrays today :)
Click to expand...
600 species?? Damn. You got me there. I'm not aware of an online tool that could do that easily. I assume you checked the literature to see if anyone (or company) has designed them before. May want to ask affymetrix for suggestions.
Hmmm.....
I suggest lots of coffee. Good luck.
 
FUCK YEAH SCIENCE.

Have a Bachelor's in Geology, did my Honours on Geochemistry/Palaeontology and started a PhD in Palaeontology/Palaeoclimatology. Probably won't finish it because I'm having too much fun using my powers for evil.
 
Bernbaum said:
FUCK YEAH SCIENCE.

Have a Bachelor's in Geology, did my Honours on Geochemistry/Palaeontology and started a PhD in Palaeontology/Palaeoclimatology. Probably won't finish it because I'm having too much fun using my powers for evil.
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Tell us more about the powers of evil;)
 
Bernbaum said:
FUCK YEAH SCIENCE.

Have a Bachelor's in Geology, did my Honours on Geochemistry/Palaeontology and started a PhD in Palaeontology/Palaeoclimatology. Probably won't finish it because I'm having too much fun using my powers for evil.
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where are you studying that? QUT, UQ?

i've heard earth sciences has some of the best employment rates and graduate salaries around. have you done much work outside university yet?

i'm thinking of returning to uni next year and studying geology is on top of my list.
 
Kyaw said:
So... time travel is sort of possible in a way that, you would only be weeks older when everything else is 4 years older when travelling at the speed of light.

We could be stuck on a vehicle going at the speed of light for about 10 years from the passengers' perspective (not from earth) and Earth's technologies would have advanced by thousands of years. We can get off the vehicle and see the future. And in a way live for millions of years. But the side effects and the energy required to do these would be make it near impossible to achieve probably.

Don't know exactly how we can go back in time without me knowing so much about quantum physics.

Please dont bash me for not understanding so much about these stuff, i'm only 16 and i want to learn these things. :)
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It's "time travel" in the sense that we are already "time traveling" forward at the normal rate (normal for us, anyway). Under relativity, FTL travel is functionally equivalent to time travel and all FTL drives are also time machines.

Causality (Cause preceding Effect) is pretty highly regarded by physicists, so time travel in the backwards direction is basically a no-go area. You can imagine all sorts of "time police" style action where the universe prevents paradoxes, but the reality is that the simplest such thing would be "disallow time travel".
 
Scrow said:
where are you studying that? QUT, UQ?

i've heard earth sciences has some of the best employment rates and graduate salaries around. have you done much work outside university yet?

i'm thinking of returning to uni next year and studying geology is on top of my list.
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Did my undergrad and Honours at QUT, the PhD I'll never finish is enrolled at UQ. Worked at the Queensland Museum whilst studying on a range of vertebrate palaeontology projects, and yes, dug up dinosaurs amongst many other amazing things.

Back when I was still studying, QUT was the 'soft rock' school (sedimentary systems - coal; oil and gas) and UQ was for 'hard rocks' (igneous and metamorphic systems - lots of graduates went to work in gold, minerals and iron). My program was amazing and we had some great talent teaching us and plenty of fieldtrip opportunities. Unfortunately, that talent is no longer at QUT and a few key players have set up shop at UQ. As such, I'd argue UQ has the better course right now.

Following my brief stint in academia, I've been working in the Petroleum industry as a geologist/palaeontologist since 2009. I love it.

It annoys me a little to say this, because I left behind some wonderfully talented colleagues in academia, but I do more real science in the private sector than I did as an academic.

As for remuneration - I really couldn't care. There's a lot of personalities like me in the industry who are just fascinated by rocks and learning how small parts of the world are put together. I could live on my current salary for the rest of my career without a raise and I'd be happy as. The pay is nice, but the real perk for me is local and international travel.
 
ThoseDeafMutes said:
It's "time travel" in the sense that we are already "time traveling" forward at the normal rate (normal for us, anyway). Under relativity, FTL travel is functionally equivalent to time travel and all FTL drives are also time machines.

Causality (Cause preceding Effect) is pretty highly regarded by physicists, so time travel in the backwards direction is basically a no-go area. You can imagine all sorts of "time police" style action where the universe prevents paradoxes, but the reality is that the simplest such thing would be "disallow time travel".
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From the Wiki page of FTL, any particle with mass would take infinite energy to accelerate up to speed of light?

This stuff is hard to get my head around because there's nothing we can relate to. Just like the size of galaxies, superclusters etc
 
Kyaw said:
From the Wiki page of FTL, any particle with mass would take infinite energy to accelerate up to speed of light?

This stuff is hard to get my head around because there's nothing we can relate to. Just like the size of galaxies, superclusters etc
Click to expand...

Yes, because as you approach c (speed of light in a vacuum), your relativistic mass becomes higher, which means you require more energy to accelerate further. The limit of this is C. Infinite energy gets you there, and... more than infinite energy gets you FTL? "More than infinite" is a nonsensical concept, so you can't just accelerate to lightspeed.

The history of people dreaming up FTL drives is the history of people trying to find a cheat to get around this. The only two remaining ones that aren't total fantasy are Alcubierre Drives (AKA warp drives, but its not really like Trek at all) and Wormholes, however these would still result in time travel if they were used. The smart money is on "we will discover a reason why these two are mpossible as we learn more about physics".
 
swordfishtrombones said:
Good luck! Do you know if there are many other candidates? A lot of labs around us have a hard time finding good PhDs and postdocs.
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I don't know, but I feel like I have a good chance, given the fact that I have a masters in both biochemistry and (soon) forensic science. And Utrecht is awesome.
 
Bernbaum said:
As for remuneration - I really couldn't care. There's a lot of personalities like me in the industry who are just fascinated by rocks and learning how small parts of the world are put together. I could live on my current salary for the rest of my career without a raise and I'd be happy as. The pay is nice, but the real perk for me is local and international travel.
Click to expand...
pretty much exactly why it's on the top of my list. you may have just convinced me to enrol in geology next year at UQ. :)
 
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