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One of our members, Bill, suggested that we start a thread where members can post questions about scientific topics for further explanation and discussion. Sounds like a good idea, so post questions and responses here.

Here's my best attempt: The sequence for the genes in question are already known from studying many individuals. If the "normal" sequence is known, then the mutation can be detected.

I was going to say about the same thing as Melissa- By taking what the norm for a gene sequence in a population is, they can compare that to the variant in question. Though I bet this gets tough to do with a smaller group of individuals, or impossible with just one gene sequence. They can also trace backwards in a non-silent mutation- By knowing what protein is not coded for correctly, maybe they can pinpoint what gene sequence must not be right. But I bet someone smarter has a better answer than me.

Here's a much stupider question: you know how at some point in high school (probably corresponding to the third time you smoked pot) you and your lame little buddies said, "What if green looks totally different to me than it does to you?" I know that's been proven invalid, because of prisms and warmth and something something, but I realized today that I couldn't explain it to someone to save my life. Can anyone give me a concise explanation?

Alex wrote: "Here's a much stupider question: you know how at some point in high school (probably corresponding to the third time you smoked pot) you and your lame little buddies said, "What if green looks tota..."

It might look different to them, perception of color is in the brain. Light at a certain frequency entering the eye creates a response in the eyes color receptors (red, green, blue). We have been socialized to say that certain responses are the various colors. But each person may have different sensitivities in their receptors and different brain processing so the colors may be different. But due to socializing when light of a certain frequency hits the eye we are all conditioned to say that is "green". My wife sees shades of color difference that I don't perceive.

In addition to what Patricrk said, consider people that are color blind. They definitely see certain colors differently than other people. The definition of Green Light by physicists, which is a light wave travelling at such and such a frequency is what does not change no matter who you are. But the human receptor isn't a calibrated machine that will return the same number every time for every human...

Bill wrote: "So one's favorite color,..."

haha, yeah, I suppose you could think of it that way. Though the differences in wave lengths is nanometers so those are pretty damn small differences.

Bill- A protein that isn't coded correctly (non-silent mutation) won't be the right shape and probably won't work the same as the non-mutation.

We're getting into areas too complicated for me. I know they can trace DNA way back, but I'm not sure exactly how they do it. (I do remember reading about mitochondrial DNA and tracing it back to early hominids.

Here's an interesting yet technical article:


I'm hoping there's someone smarter and more up to date on this stuff that can answer your questions.

I believe there has been extensive study of mitochondrial and nuclear DNA obtained from mummies and fossils. Especially to support the evidence for the origins of modern humans.

And I am by no means smarter or more up-to-date than Ami, so hopefully someone else on this forum can help with this . . .

Bill wrote:(I'd be surprised if dna was extractable from fossils

Seems pretty remarkable to me as well . . .

BBC news 2005:


More recently, from the NYT:

Does anyone know if this is for real, or is this a joke:



I don't know anything about this website, but I'm not sure I'd consider it a reliable source of science news.

Betsy wrote: "Does anyone know if this is for real, or is this a joke:

Scientist cure cancer but no one takes notice.

I don't know anything about this website, but I'm not sure I'd consider it a reliable sourc..."

Betsy, here is a blog-post from someone I think you can trust:

Thank you. I thought it had to be something like that.

Bill wrote: "Ami wrote: "Bill- A protein that isn't coded correctly (non-silent mutation) won't be the right shape and probably won't work the same as the non-mutation.

We're getting into areas too complicat..."

Actually, I've read about soft tissue cells and I think DNA being discovered and extracted from fossils... I will see if I can track down which book or magazine I found that tidbit in.

Also I think there can be a cultural element to what color is described linguistically. What we would describe as two different colors (say 'blue' and 'green'), might be described as shades of the same color.

Although I guess this could be a matter more of how different cultures can teach us to conceptualize things differently, even "obvious" things like color.

(Long ago I took anthropology, and this is what I seem to recall being taught.)

I recall taking an intro psychology class, and our professor got terribly excited when we were discussing color-blindedness, and he discovered someone in the class was not only red-green, but also blue-yellow, colorblind. He had found a new guinea pig!

Here is a question for you space geeks. Why don't we build a Geosynchronous Space Station and develop vehicles that can travel between low earth orbit and the GSS? By doing so, wouldn't we learn how to refuel vehicles in space? Wouldn't we be creating technologies that would allow us to build stations farther away from space? Wouldn't this be a lot simpler than trying to build a station beyond the moon? Wouldn't it be safer for the personnel manning the station?

Patricrk wrote: "My wife sees shades of color difference that I don't perceive. "



Women often see more hues than men do, probably something to do with our history as gatherers, whereas men hunt, and just need to see large (ish) objects moving against other large(ish) objects. Women needed to be able to differentiate between foods that were ripe, and that were dangerous, and to have good colour differentiation to spot the dangerous foodstuffs and the safe ones.

Also, there are a rare few women who are tetraconal, meaning they have 4 types of cone light receptors, rather than the usual 3. This doesn't increase the amount of the light spectrum they can see, it doesn't let them see ultraviolet or anything like that, but it does give them absolutely amazing colour differentiation abilities.

The interesting thing here is that women who are tetraconal all seem to have sons (assuming they breed and produce sons) that are colour blind. Tetraconalism has not be found in men, so far.

Stan wrote: "Here is a question for you space geeks. Why don't we build a Geosynchronous Space Station and develop vehicles that can travel between low earth orbit and the GSS? By doing so, wouldn't we learn ..."
I don't see the connection between GSS and learning how to refuel in space. That is a technology that can be practiced in low earth orbit. I thought the moon station was proposed as a location where the moon would serve as a shield for radio interference from earth. I agree any earth orbit is probably safer than a lunar station. I also agree that being able to refuel in space would be a great technology as long as rocket engine components have adequate life and don't wear out after only several hours of use.

Patricrk wrote: "Stan wrote: "Here is a question for you space geeks. Why don't we build a Geosynchronous Space Station and develop vehicles that can travel between low earth orbit and the GSS? By doing so, would..."
A station like you suggested could prove to be a very useful as a sort of 'intermediate' station. This way, space travel to further distances won't waste too much fuel on take-off. Rocket design will also be much easier to handle since they wouldn't have to think about the re-entry into earth's atmosphere and the initial take-off from earth's gravity. Instead,design for rockets in this docked in this 'intermediate' station would only have to focus on speed and energy-conservation. Over-heating and even safe-landing would not be a big problem. Geez, the difficulties of landing on earth are just too many I can't barely mention them all without getting a headache.

What Patricrk (above me) said about a lunar station being more hazardous that an earth orbit station is true. With lunar stations, we would have to worry about (again) the moon's gravity. Besides, the moon's surface isn't entirely smooth, so landing might not be the easiest task.

Hazel wrote: "Patricrk wrote: "My wife sees shades of color difference that I don't perceive. "



Women often see more hues than men do, probably something to do with our history as gatherers, whereas men hunt,..."

That's really interesting, and I'm not just saying that! I always thought that men simply never care about the subtler hues between blue and green (for example). But there has been something that's nagging me. The rare fourth type of cone present in certain women; which color does it exactly perceive?? From what I have heard, is that the initial red, blue and green cones the rest of the human population has are sufficient to see all the colors of the rainbow we know of (that also includes all the subtle hues in between). Theoretically, a new cone should give these women the ability to see a new kind of color. Maybe not infrared or ultraviolet, but an addition the light spectrum of the rainbow. For people who are colorblind, they will perceive the colors they can't in another color. E.g blue as grey, yellow as grey. So perhaps for us (the normal people with three types of cones) will see much more grey that the tetraconal women. Maybe this grey shirt I am wearing isn't grey at all!

Nonetheless, I do agree with you that maybe women's past as the herb collectors may have given rise to this evolutionary trait.

Stan wrote: "Here is a question for you space geeks. Why don't we build a Geosynchronous Space Station and develop vehicles that can travel between low earth orbit and the GSS? By doing so, wouldn't we learn ..."

This has been considered but at the moment it seems that the Lagrange points make more sense. There are five LaGrange points for every two-body system. The two most likely for use as a refueling and service station are EML1 and EML2. The former is about 85% of the way to the moon, the latter behind the moon at a further distance.

The advantage of these points is that the gravity of the Earth and Moon cancel each other out at these points which makes it much easier to maintain station with much less fuel use for station keeping. You don't have the gravity well of the moon to deal with during arrivals and departures, which again means less fuel and bigger payloads.

Stations at these points could, in addition to fuel, could provide satellite repairs, telerobotic operations on the moon (far side especially), asteroid processing (for small asteroids towed into lunar orbit), and waystation accomodations for astronauts headed for the moon, asteroids or Mars.

"The Space Review" newsletters has had some very good articles on this topic.

Irene wrote: "Patricrk wrote: "Stan wrote: "Here is a question for you space geeks. Why don't we build a Geosynchronous Space Station and develop vehicles that can travel between low earth orbit and the GSS? B..."
certainly if you are designing only for vacuum and don't have to worry about reentry you can design different looking vehicles. But, unless you are getting your fuel from some other place than earth the fuel savings aren't there. If you left from lunar orbit to go to Mars and returned, you would still need to slow down to lunar orbit speed on your return which will take a large fuel requirement. The Apollo capsules came straight back from the moon because the fuel requirements to slow them back down were as high as the fuel it took to get them to the moon in the first place.

Thanks for all the answers about a GSS. My vision is of a station filled with commercial technology to help pay for it. I see the chance to develop a vehicle that has magnetic shield technology that can be tested in real life situations. I see training for pilots, and I see the last stage, a station in low moon orbit from where vehicles from Armadillo, SpaceX, and Maston regularly land on the moon field.
And there is another reason for the GSS, and this is that there is a huge segment of taxpayers who believe that any space exploration is a waste of money. A intermediary station might be more palatable to them.

Patricrk wrote: "Irene wrote: "Patricrk wrote: "Stan wrote: "Here is a question for you space geeks. Why don't we build a Geosynchronous Space Station and develop vehicles that can travel between low earth orbit a..."

I see, I hadn't considered that space vehicles also need to slow down to enter an orbit. But I believe that re-entering earth orbit will still take less energy than to re-enter lunar orbit, since the moon's gravitational pull is far weaker than that of earth's. Thus, when space vehicles re-enter earth orbit they wouldn't have to slow down as much. I'm not aware of the exact mathematical formula for this, but could there still be chance that leaving and returning to earth orbit (instead of the earth itself) will still use less fuel?

(to Stan) Now that I think about it, a station orbiting in low earth orbit has quite a lot of disadvantages. Perhaps, it is still better for humanity to stick to earth-bound stations in the meantime. We will still need to develop a more reliable technology to maintain a thriving eco-system in outer space. This way, we wouldn't have to make so may trips from earth back to the station just to deliver food and fuel and take away waste products. Wouldn't it be awesome if we will one day have an independent eco-system in space?

Irene wrote: "Patricrk wrote: "Irene wrote: "Patricrk wrote: "Stan wrote: "Here is a question for you space geeks. Why don't we build a Geosynchronous Space Station and develop vehicles that can travel between ..."

Actually, I think that it takes less propulsion to enter earth's orbit than the lunar orbit, but for a different reason. Space capsules burn off a lot of energy when entering the atmosphere at high speed, thus slowing it down.

David wrote: "Irene wrote: "Patricrk wrote: "Irene wrote: "Patricrk wrote: "Stan wrote: "Here is a question for you space geeks. Why don't we build a Geosynchronous Space Station and develop vehicles that can t..."

if you have a capsule (or space craft) designed to enter atmosphere you are right you can lose some energy by friction in the atmosphere. But, I thought we were talking about orbit to orbit craft that are not expected to enter an atmosphere.

The original poser of the question about space stations or depots seems to have departed the group, but if any of the other contributors to the discussion are interested in the topic, here is a current and thorough article on the topic of "space truck depots" at Earth-Moon Lagrange points:

Steve wrote: "The original poser of the question about space stations or depots seems to have departed the group, but if any of the other contributors to the discussion are interested in the topic, here is a cur..."

Excellent article. One of the best I've read. I wonder what other types of propulsion might be used. I wonder if a modified VASIMR engine could be used.



One of the most annoying aspects of NASA is that the people running it are so interested in the science that they seem to neglect the infrastructure. Why wasn't Mars ringed with satellite cameras that could explain the loss of equipment before we attempted to land very expensive equipment?

Hi! Wonderful to find this group. I'm hoping that someone can help me out with a chemistry qusetion. I've been plotting a short story where I'd like to include a chemical reaction that produces the same sort of carboniferous layer as burning, without actually burning plants etc. Is there a reaction which might produce this? Maybe precipitating it out of the atmosphere?
Any help much appreciated!

Stan wrote: Why wasn't Mars ringed with satellite cameras that could explain the loss of equipment before we attempted to land very expensive equipment?
"

Very good question.

Hi Krishna,
An atom undergoing beta decay does indeed become charged; but it instantaneously gains an electron from the neighbourhood and attains electrostatic stability. If it were possible to view only one atom undergoing beta- decay in complete isolation, one would see that a new nucleus is formed with one unit higher atomic number and it has the same number of outer electrons as before - hence, positively charged.
In beta- decay, a neutron undergoes spontaneous decay due to the weak nuclear force to generate a proton and an electron; a neutrino is also produced as parity must be conserved. The neutrino (there are hypothetically 3 varieties that may be produced) takes care of the colour conservation.

Avik wrote: "Hi Krishna,
An atom undergoing beta decay does indeed become charged; but it instantaneously gains an electron from the neighbourhood and attains electrostatic stability. If it were possible to vie..."

And just to round this out, lepton conservation is preserved because it is an antineutrino that is emitted; so the electron and the antineutrino "sum" to zero total leptons. There was zero charge before, and there is zero (total) charge afterward (the proton and new electron sum to 0), so charge is conserved. There was one baryon before (neutron) and one afterward (proton), and so baryons are conserved.

Yes Daniel, you are spot-on. There are 3 very similar processes that come under the umbrella term "beta decay" - beta minus(-) decay, positron emission and electron capture. 3 different varieties of neutrinos take care of the lepton/baryon conservation in these 3 cases. That's what I meant, and also mentioned in my previous reply.

the idea of polarity is derived from wave mechanics. so, a stream of photons constituting a wave can be polarized. a photon in isolation cannot.

I knew I liked paper books better than ebooks & thought that I got more out of them. I put it down to some deep seated prejudice on my part. Something deep down in my brain just kept rejecting etext as a real book or something. After all, I do still print out some bits of tech manuals, but usually only those parts that I plan to annotate. Well, it's not just me.

Research suggests that recall of plot after using an e-reader is poorer than with traditional books


Does anyone know of any other studies supporting this?

Jim wrote: "I knew I liked paper books better than ebooks & thought that I got more out of them. I put it down to some deep seated prejudice on my part. Something deep down in my brain just kept rejecting et..."

I don't know of any studies right now, but you have definitely pique my learning bone; so, I'll have to do some online research.

I know for myself, that it's easier for me to highlight--sacreligious for a print book--and take notes. It is also much easier for me to retrieve this information. For me, reading and ebook is much more enjoyable; it so much easier to navigate, check progress, and search the text. Because of these things, I feel that my comprehension is higher with ebooks, rather than a print book. It did take a while to get into ebooks after decades of reading print books. One more benefit to an ebook, is the ability to link to a dictionary, which is another boost to learning.

Betsy wrote: "Does anyone know if this is for real, or is this a joke:

Scientist cure cancer but no one takes notice.

I don't know anything about this website, but I'm not sure I'd consider it a reliable sourc..."

When considering the validity of any scientific research, it is important to stick to work that has been published in a peer review journal. It pays to beware of work appearing in another type writing that does not give the source for that information.

Steven wrote: "Jim wrote: "I knew I liked paper books better than ebooks & thought that I got more out of them. I put it down to some deep seated prejudice on my part. Something deep down in my brain just kept ..."

For me, e-books have given me back the ability to read--period. My vision isn't great these days, and trying to read paper books is very tiring. E-books let me increase the font size whenever I need it and allow me to adjust the brightness of the display. (The Kindle reading app is especially good for that.) I certainly miss some things about print books, but I am just delighted to find that, thank to e-books, I can read for pleasure again. That said, I do get frustrated when I discover that a book I really want to read isn't available as an ebook, or at least isn't available as an ebook through the public library.

Steven, I don't think it's sacrilegious to mark up paper books that I own. I don't understand why people feel this way. I write in margins & use sticky notes, too. You should see some of my tree books. They have dirt & leaf chaff in them, too. They're working books. I tend to read them then pull them out for reference & make notes in them. Some are stuffed with printed articles, too. I do like ebooks for searching & really appreciate having both available.

Laura, I don't think your case is what they were looking at, but I hear you. My eyes have gotten a lot worse, although they're pretty good by most standards. Still, it's nice to be able to crank the font up a notch.

I like being able to adjust the font in e-books, but it's the light weight and small size that I really appreciate. I've got moderate arthritis in my hands, as well as carpal tunnel, so holding a heavy book at a decent reading angle and height, including many paperbacks, is a big problem.

I had the Kindle DX and then a Kindle Fire (which I still use on occasion.) I bought or otherwise loaded hundreds of books onto it, over the course of two-ish years. The Kindle(s) have a number of advantages, but I've since gone back to paper books for a number of reasons.

(1) I like to actually own the books I buy (looking at you, Amazon), including disposing of those books as I see fit (lending, giving away, selling, throwing away in disgust).

(2) For textbooks, math books, etc. in particular, I prefer a paper book. The ability to put my fingers in 3 or 4 different sections and rapidly flip back and forth, or know where something is and flip the book open to within a few pages is still faster/easier in a paper book.

(3) I'll admit to a certain kind of vanity; I like having my books shelved, it looks 'cool' to my eye.

(4) I've yet to have a book run out of battery. And books are durable; I regularly toss books next to me on the floor (at my desk...), across the room onto our bed, into my satchel, etc.

Oh, and marking up a book is sacrilegious! :) My bother does that. We have developed a permanent armistice regarding it after the "Snow Crash" incident of '95, but I've never really forgiven him :)

I hope I am on the right thread, by that ie, there is a chance my query, would take notice from the most prominent members here


So here it is, a book, from a prominent author, whom I worshiped for his insight on the late 90s. I wanna know more, about what is happening, on the 'growing field' of Astrobiology
[ used to be 'coined up' under exobiology, but the above term, gathers way many more disciplones, under its shadow]
So here it is
/book/show/1...
I will be able, to get this for afraction of it's price, but so far, i wasn't able, to find a 'readable sample' I would really apprciate, if any of you here, could give some pointers, or if it is 'out of yr sphere' of interests, point me to another author/book

Amazon:

He was in charge of the Mars Maven project for NASA. He works in the CU Boulder LASP lab.

There are a number of books on alien life from very serious and simple to fantastic speculation on what alien lifeforms might look like.

Kenny wrote: "

He was in charge of the Mars Maven project for NASA. He works in the CU Boulder LA..."
Yeah i know that already, he has been also the project manager here for quite sometime
Well kENNy i do wonder, if anything new has come up, since then.. still I don't know the implications-- or any 'loose info' of the Mavn Project [ i doubt, if they got any books, on that one either] But from a quick look, I can tell, that Me Jakobsky, has been rather busy, the last few years

Note:Both of yer links ain't helping, and yeah I've seen the Amazon link, blanck, it came up empty..nowhere

The hummingbird season is reaching its height now. Yesterday I had to make up 8 cups of sugar water. I have 4 feeders out. It's great watching them form clouds around the feeders & surprising. I was feeding 10 cups per day last year & usually that would mean a lot less birds this year. We've never had 2 years in a row with so many.

The front feeder doesn't get much traffic during the day, but something is emptying the feeder each night. It's not a squirrel or raccoon since the feeder isn't missing parts. It has little flowers that poke into the feeding holes & come out fairly easily, so I can tell when something big gets to the feeder. Whatever it is sucks the feeder completely dry, too. There isn't anything left in the bottom. That's typical of a woodpecker draining it, but they don't fly at night. We do see them on it occasionally, but I'm up before dawn & I check the level before going to bed after dark. I've got no idea what could be sucking at least half a cup of sugar water down in a night. Any ideas?

I'm tempted to get a trail cam or something to find out, but I'm completely ignorant about trail/remote cameras. There is a huge choice. Does anyone have any experience with them? There are some fantastic still & video cameras available for reasonable prices, too many for me to choose from easily. Some shoot both IR & regular light which would be best. I could leave the front porch light on if IR pics weren't good enough. Any thoughts?

I have a Campark WLAN Wildkamera 4K 30MP Bluetooth camera that I really like. The pictures are sharp and the battey life is about a month . much linger than other cameras I have used. There is also a timer, which allows me to set a start time and an end time.

Thank you, Charise. I'll look into it.