Farthest Human-Made Object: First Quarter Century 405
An anonymous reader writes "The NASA Astrobiology Magazine reports today the 25th anniversary of the Voyager I launch, now the farthest human-made object at 93 Sun-Earth distances (93 AU), or 12 light-hours away. Expected battery life to 2020. The fascinating part is that gold record of civilization, which is a strange audio mix of sentimental kisses [wav file, let ET phone home that way] and perhaps the most dated picture of DNA. Some progress there. Voy 1 will likely confuse even modern earthlings-- much less ET. Case in point: In 2002, can we understand that 70's show, when the Polish greeting memorialized as "Welcome, creatures from beyond the outer world"? Unlike those ET creatures we meet daily from the inner world?"
Deep Shi~H~H~HSpace (Score:2)
Which is odd (Score:2)
Re:Which is odd (Score:2)
Re:Which is odd (Score:2, Funny)
They've found it now (Score:2)
Simon
Sending that record was a great idea (Score:5, Funny)
Wish I was gonna be around to watch all this.
Re:Sending that record was a great idea (Score:3, Funny)
I don't you need to be - because apparently this version of the future is based on a poor SciFi B-movie. They've probably got one a Blockbuster you can rent instead.
Re:Sending that record was a great idea (Score:5, Funny)
Re:Sending that record was a great idea (Score:3, Funny)
Nah, there's the old joke about how hundreds of years from now, Earth finally receives the long-awaited message from another civilization. The people wait anxiously while the scientists translate the message. Finally the results are announced. "We have found your artifact," the message says, "Send more Chuck Berry."
Re:Sending that record was a great idea (Score:2)
Perspective (Score:5, Interesting)
Re:Perspective (Score:2, Funny)
-Rick
Re:Perspective (Score:5, Funny)
"Ha! Look at the cute little spacecraft the earthlings sent out thousands of years ago! How pitiful!"
"Shut up, give it back!"
"Oooh, I bet the guys on Gallus V will really get a kick out of this. The Big Bad Earthers and their cute little tin-foil spacecraft!"
Kind of like when your big brother finds a picture of you in the bathtub at age 9 months and threatens to show it to your friends.
Re:Perspective (OFFTOPIC WARNING!) (Score:2)
Re:Perspective (Score:2)
Dead in less than a light day (Score:2)
Re:Perspective (Score:3, Interesting)
This problem really annoys me, because it seems nobody gives a thought about how we will communicate or travel in space. It takes from 3 to 20 minutes for radio waves to cover the distance between the Earth and Mars depending their position around the Sun. Which means you can never phone to Mars from Earth, because you get an answer for your question in about 6-40 minutes. In our rushing world thats a lot of time.
As for travelling in space the twin paradox poses another problem. If we can reach almost the speed of light by some method we have to face this relativity problem. If you step in your space ship and after 1 hour you step out on Alpha Centauri you will have to face with the fact in the "real" world 4 years passed. Communication with Earth is quite futile also, because they get your message in 4 years.
In short, if Einstein is right we are in a dead end. So, I want to beleive there is worm hole or hyperspace or whatever which makes space travel possible otherwise humanity will stuck to this planet forever.
Or, as I hope, Einstein is not right. I hope a genius in the future will invalidate Einstein theory as Einstein invalidated Newton theory. It is interesting that nobody dares to say, but Newton theory about gravity and his equations were completely shattered by Einstein on the theoretical level. On the practical level we use them, because they are not so complex as Einstein's and provide us with the neccessary precision, but this does not do anything with the fact that Newton's theory is wrong.
I don’t see why its disappointing. (Score:5, Insightful)
1000 years ago, it took years to go or communicate from one end of the known world to the other.
250 years ago, we reach the new world. But it still took most of a year, and the danger of shipwreck to get there.
In 100 years from now we may have very fast ships. Lets say 10% of light speed. This would put us on the nearest star in 40 years. People who go on that mission will be expecting it to be so. Civilization is not a one mans cause; it's the perspective of generations.
Re:Perspective (Score:2)
And if you step out on Alpha Centauri itself, I think what's going on at home will be the least of your problems.
Anyway, I hope you are right about Einstein not being right. I really need to try to understand relativity sometimes - to me if you go at the speed of light for 4.2 years to Alpha Centauri, then 4.2 years should have passed - both for you and at home.
I guess I just refused to accept that the speed of light is the limiting factor....kinda like saying that time goes backwards if you go over 55mph on the highway.
All we really need to do is find a huge pocket of melange though and all our problems are answered.
Re:Perspective (Score:2)
If I'm accelerating to the speed of light, at various points I'll be travelling at various speeds - 5mph, 10mph, 10000mph, etc... At 5mph going up to 50mph, a second is still a second right and if it takes me 30 seconds to go from 5mph to 50mph, it takes me 30 seconds, my vehicle 30seconds and the earth 30 seconds.
So if it takes me 1 day to accelerate to the speed of light (cause of the new spoiler on the back of my honda spaceship
Do you know of a good web site or book on this - I'd really like to understand it.
Lightspeed travel for dummies perhaps?
Re:Perspective (Score:2)
Try goole with words "usenet physics faq".
Re:Perspective (Score:2)
No. If you were going away from the earth at half the speed of light, in one second of your time, 1.15 seconds would go by on earth 1/sqrt( 1 - (v/c)^2). From the other perspective, in one second on earth, 1.15 seconds would elapse on your spacecraft. The paradox is left to students of the Lorentz Transformation.
If you were travelling at the speed of light, in one second of your time, not-a-number seconds would pass back on earth. As you get closer and closer to the speed of light, clocks on earth go slower and slower.
Re:Perspective (Score:2)
Re:Perspective (Score:2)
Newton's physics is "good enough", except at very high speeds or very dense gravitational gradients. Experiments have confirmed those subtle discrepencies between reality and the predictions of the theory. Einstein's physics is "good enough" in those cases... Feel free to study Einstein's theories, and figure out an experiment to perform to show that he was wrong.
We shall see whether humanity is stuck on this planet forever (errr. for mumble billion years before the sun swells to its red-giant phase and vaporizes the planet...) or we make it out to the solar system, or even the stars.
It may take hundreds or thousands of years before we have the wealth and the ability and the desire to create a civilization off of this planet.
How quickly could we catch up... (Score:2)
Re:How quickly could we catch up... (Score:3, Interesting)
Re:How quickly could we catch up... (Score:2)
Re:Perspective (Score:2, Funny)
That's Light Hours, not Light Years (Score:2, Informative)
12 light years would require it to fly at ½ the speed of light, which is not technichally feasible (unfortunately!)
Re:That's Light Hours, not Light Years (Score:2)
Comment removed (Score:3, Informative)
Re:Carl Sagan and the stellar record. (Score:2, Informative)
Re:Carl Sagan and the stellar record. (Score:3, Funny)
2012-ish marks next 'landmark' event for Voyager.. (Score:4, Interesting)
Pretty neat for a piece of 1970's technology.
Re:2012-ish marks next 'landmark' event for Voyage (Score:2)
Not really. I mean, the journey it made, the navigation around the planets to gain more speed was pretty impressive, but in my view it is not impressive to leave to solar system. You see, on the next Shuttle flight they could bring a 16th century vase, and hurl it into space. Give it a few years, and it will too leave the solar system, but is that neat, or impressive?
You have no idea what you're talking about. (Score:3, Informative)
Besides, your analogy falls flat. I presume your point was that the age of the technology is irrelevant when it comes to leaving the solar system? Then consider this: what is it that pushed the 1970s technology of the Voyagers out of the solar system? Answer: more 1970s technology. If your 16th century vase were propelled by 16th century rockets, then your analogy would be valid.
Re:What is the heliopause? (Score:3, Informative)
The sun emits a flood of mostly-charged particles that make up the "solar wind." The earth is shielded by its magnetic fields, but the interplanetary environment is quite harsh.
The heliopause is where this outward flow of solar matter becomes less than the general flow of matter through the galaxy. There isn't any good way to observe this from earth, which is why having a Voyager pass through the area is a good thing. Our current picture of the heliopause is based on physical modeling and simulation. Having any observational data to check these models against would be a major step forward.
Re:2012-ish marks next 'landmark' event for Voyage (Score:3, Funny)
By bouncing off the forehead of a numbskull
The music on there (Score:3, Funny)
Re:The music on there (Score:2)
"Bach, all of Bach, streamed out into space, over and over again." He added, "We would be bragging, of course."
ObRef: Thomas, L. Ceti. in Lives of a Cell: Notes of a Biology Watcher, Viking Press, New York, 1974, 42-46
Re:The music on there (Score:2)
There's an info page on the message to the universe here [nasa.gov].
Bach has 3 pieces on the record, compared to 2 by Beethoven and 1 each by Mozart, Stravinsky, Chuck Berry, and Blind Willie Johnson. I'd say the selectors did a pretty good job as far as the classical western genres are concerned.
(2 by Beethoven is over-representation? Possibly, but one is from one of the sublime late string quartets.)
DNA is still DNA (Score:5, Insightful)
Huh? Unless something changed recently, all the details illustrated in the DNA diagram are still as valid now as they were in the 70s. Is the story submitter upset because the double helix isn't animated, spinning slowly around, backlit by an offscreen purple fluorescent light source with meaningless reams of genetic code flashing past in the background like in a million bad sci-fi movies?
You'll still find a very similar style of diagram in any molecular biology textbook.
Why do they give Aliens our DNA? (Score:5, Funny)
If aliens decide to take over the world, well theres a map, our DNA so they can change their genes to look exactly like us, some wav files so they can learn how we talk and maybe even our language from the greetings. What the hell are Nasa scientists doing? Where is the government and national security?
I mean damn shouldnt the NSA outlaw us putting DNA into space and maps, I dare the scientist who gave our DNA to aliens to post his social security number and credit card number on the internet in plain text!
Re:DNA is still DNA (Score:2, Interesting)
Re:DNA is still DNA (Score:3, Informative)
I used to own the hardcover, but it disappeared one day, along with my copy of A House in Space [amazon.com], the story of the first space station, Skylab.
Re:DNA is still DNA (Score:2)
Alien 1: Let's kill their President!
Alien 2: How?
Alien 1: Let's frame him for murder in Texas!
Golden Record (Score:3, Informative)
How odd that the first human voice any aliens who could work the disc will hear is the voice of a former Nazi alleged to have taken part in war crime atrocities in the then Yugoslavia...
Re:Golden Record (Score:2)
Re:Golden Record (Score:2)
Re:Golden Record (Score:2)
Infinity taken for granted (Score:2, Interesting)
Often scientists talk about how the universe is expanding. The concept of expansion itself demands that a boundary be present. And boundaries demark two regions, one within and one beyond. Yet nobody dares mention what is beyond the universe.
All these contradictions just tell us one thing. Alot has to be undone about our stake of knowledge before we can begin to truely understand.
Our current state of knowledge is similar to the days before Galeleo, when people thought the world was flat and you could reach the end of the world.
My 0.02
'Cause they lie (Score:2)
Re:Infinity taken for granted (Score:2)
What??? (Score:2)
That's a nice sentence fragment you've written. Try full sentences next time. You might like them.
Re:What??? (Score:2)
On a less sarcastic note, the point of the record is not really to communicate to aliens. By the time any aliens get the record, the Earth might even be long gone. Any aliens who find this probe will know that there was (or is) some form of intelligence in the universe. Maybe they won't even understand the concept of "sound" as a medium of communication, but it will be clear that this was the product of a civilization. Perhaps the effort to decode the disk will be a source of enlightenment or inspiration for the aliens, even if it isn't successful. If the message were totally straightforward, it might seem trivial. You've got to leave some part of it mysterious, to give them something to chew on and wonder about.
Secondarily (or is it primarily...), it is made for the people of Earth, to know that some remnant of our humanity is floating, practically eternally, through space, even after the Earth is destroyed by solar evolution. That this disc has deliberately tried to preserve sounds that represent a diverse range of humanity is a hopeful gesture, like a time capsule, that no matter what happens to humanity, each of us can know that Voyager represents us in some small way.
Re:What??? (Score:3, Interesting)
If so, I would hope that the spacecraft would be analyzed in situ and allowed to continue rather than being returned to Earth and stuck in a museum.
Kind of OT but ... (Score:2)
I don't know about anyone else but I get this quite erie vision of this thing out there with nothing around it for millions of miles.
silly question (Score:2)
Yes, for sufficient money (Score:2, Informative)
First cab off the rank is probably the Orion drive. Build a really big plate, attach it with really big springs and dampers to a heavily radiation-shielded spacecraft, and detonate atom bombs behind the plate. The basic technology exists right now, all you need is a pile of cash and be prepared to violate the space weapons treaty. Maximum speed is about 1-2% of the speed of light, so you're still taking a couple of centuries to Proxima Centauri.
Next option is a fusion engine. We can't generate power with controlled fusion yet, but ITER probably will if and when it gets built. ITER is, er, rather large and heavy, and doesn't really produce much net power, so a practical space fusion power plant is a fair bit of engineering development down the road. Anyway, the idea is quite simple. Release the "exhaust" of the reaction out the back of the engine, just like a normal rocket except the exhuast is a hell of a lot hotter and travelling a lot faster. Maximum speed maybe 10-12% of the speed of light.
Alternatively, use a light sail powered by a really big laser. All you need is to scale up laser and telescope technology a crapload (so, again, considerable engineering development required). Maximum speed? Somewhere between 10 and maybe 30% of the speed of light, depending on just how big you can make your mirror (and consequently how far you can keep accelerating).
The other big issue with interstellar spacecraft is the question of how much debris is out there. If there's a lot, as you go faster you'll need one hell of a shield to protect you.
Finally, there's there's also the possibility of using antimatter-matter reactions to power a ship. Antimatter is kinda powerful stuff to have around, and you could theoretically use it to power a ship to near the speed of light. However, there is no known natural source, and manufacturing it requires milllions of times more energy put in than you get back when you "burn" it. It, therefore, is a really long-term option from when humanity has such astounding energy generation capacity it can afford to use it to power antimatter-powered spaceships.
All in all, there are some possibilities, but most are still a fair bit of technological development away. Let's get to the rest of the solar system first :)
Re:silly question (Score:2)
93000000 * 3.6 = 334800000 miles per year
dividing by ( 365 * 24 ) gives
voyager speed = 38219 miles per hour (a shade over 10 miles per second, or 0.000057c)
My Polish is rusty, but... (Score:4, Informative)
I think it would be an equivalent of "Greetings, creatures from Outer Space," but they didn't intone it pretentiously, right before Ed Wood hovers the hubcap from a string and a theremin plays in the background as his boustier intrudes into the picture, as we are wont to do over here.
Re:My Polish is rusty, but... (Score:2, Informative)
Re:My Polish is rusty, but... (Score:2, Funny)
Sounds of Earth (Score:2, Interesting)
If you found this record do you think you could play it?
And extract the images from it?
I have the directions http://vraptor.jpl.nasa.gov/voyager/messages/VgrC
and it would still be pretty tricky.
If I didnt have them I dont think I would have any chance of figuring out what this thing was.
-M
Stellar escape velocity (Score:4, Interesting)
If I'm plugging in the equation right, taking into account the 93 AU that the Voyager has already reached, and the present speed (39,000 miles an hour, assuming none of that's tangential velocity), I get a required speed of 4000 km/s, and the Voyager is going far slower.
So as far as I can tell, really the gold record, etc. on board are more of a time capsule for when the craft swings back around on its comet-like trajectory, rather than for contacting aliens. I think the nasa people and popular science writers like to preserve the more romantic notion of an unintentional first instellar voyage, though my calculations could be wrong.
Re:Stellar escape velocity (Score:3, Informative)
Escape velocity from the Sun at a given radius,r, is just sqrt(2*G*M_sun/r). Plugging in (G=6.67e-8 in cgs units; M=2e33 g; r=93 AU = 93 *(1.496e13 cm)), I get v_escape of about 4.4e5 cm/s, or 4.4 km/s. (About 15,800 km/hr, or 9800 mi/hr, safely less than Voyager's velocity.)
It was an interesting thought, though. :-)
We should create Voyager III (Score:5, Funny)
On board we also include a copy of Lord of the Rings in DivX format and Mp3's of Britney Spears. That way if the aliens invade, we can tell the RIAA and MPAA they have pirated movies and music and watch the aliens recoil and flee under the unsuing crush of lawyers and DMCA threat letters.
If that doesn't work, we trick them into installing the cracked copy of WinXP convieniently on stowed board and watch their ships fail in horrible and astonishing ways.
Now if that fails, then we trick them into installing AOL and logging onto it. After all nothing can withstand humankinds most powerful weapon... Pure stupidity.
Pluto pobe Voyager III (Score:2)
Before you rush off to tell your friends... (Score:2)
Not the furthest mad-made object?! (Score:5, Interesting)
"Project Thunderwell was the inspiration of astrophysicist Bob Brownlee, who in the summer of 1957 was faced with the problem of containing underground an explosion, expected to be equivalent to a few hundred tons of dynamite. Brownlee put the bomb at the bottom of a 500-foot vertical tunnel in the Nevada desert, sealing the opening with a four-inch thick steel plate weighing several hundred pounds. He knew the lid would be blown off; he didn't know exactly how fast. High-speed cameras caught the giant manhole cover as it began its unscheduled flight into history. Based upon his calculations and the evidence from the cameras, Brownlee estimated that the steel plate was traveling at a velocity six times that needed to escape Earth's gravity when it soared into the flawless blue Neavada sky. 'We never found it. It was gone,' Brownlee says, a touch of awe in his voice almost 35 years later.
http://www.geocities.com/CapeCanaveral/Hall/189
Re:Not the furthest mad-made object?! (Score:2)
Re:Not the furthest mad-made object?! (Score:3, Informative)
See This page [enviroweb.org] for details about the real test (search for "Pascal-B").
Poor Polish Translation... (Score:2)
Are we sure? (Score:2)
How impossible is it that a pottery shard was included in some ejectile material 25,000 years ago... and given the likely orbits of something like that, how far could it have gone?
Copyright Abuse: Et Tu, Voyager? (Score:2)
Re:Battery life? (Score:4, Informative)
Looks like the isotope's power the battery.
Re:Battery life? (Score:3, Informative)
It has nothing to do with environmentalism (Score:5, Insightful)
It's a shame that the environmentalists had a hissy fit in the 80's and 90's that blocked this very reliable technology from being used on modern spacecraft.
Not really. The problem is that in order to make one of these generators safe, it needs to be protected from the launch rocket exploding on take-off. It doesn't matter whether you're an environmentalist or not - if a couple of kilos of plutonium gets vaporised and spread to the four winds on the launch pad, you've just made enormous chunks of the US's only major space launch site unusable until it can be cleaned up. You can stick your head in the sand about it, but that doesn't make the radiation go away. Needless to say, the clean-up operation and interruption to US space activities would cost tens of billions of dollars - and quite possibly a lot more.
It's perfectly possible to protect these generators from the explosive force caused by a rocket blowing up on the launch pad - it's just a simple engineering problem. The problem is that it costs weight - lots of it, and the number one thing you want to avoid on a rocket launch is extra weight. Every extra kilogram costs you hundreds of thousands of dollars, or costs you one or two or three valuable scientific instruments.
So unless you absolutely need a radioisotope thermoelectric generator, you don't use one. Solar panels are lighter (because they don't need explosion protection) and, therefore, cheaper to launch (which is the only really major cost consideration - the cost of the space vehicle itself pales in comparison). Modern solar panels are good out to nearly Jupiter. Beyond that you need an RTG. I can only think of one mission that NASA has launched since the Voyagers that has gone out that far - Galileo, which was launched in 1989 - and yes, it had an RTG on-board despite the protests.
Honestly, NASA - at least the engineers - couldn't give a damn about the environmental issues involved with RTGs. Because as long as their containment engineering is up to scratch - and I rather suspect it is - there simply are no environmental issues. Instead, it comes down to economics - and for most missions that NASA undertakes, which go no further out than Mars, thermoelectric generators lose out badly to solar panels.
Now, perhaps environmentalist fears are preventing NASA from sending more probes beyond Jupiter because they need an RTG, but that's a different matter entirely. Maybe they need to publicly blow up a few rockets with the generator containers on-board to prove their point.
How could I forget? (Score:2)
I can only think of one mission that NASA has launched since the Voyagers that has gone out that far - Galileo
Cassini, as well. Which, surprise surprise, also has an RTG on-board.
Re:Battery life? (Score:2)
Looks like it was solar/battery http://mars.jpl.nasa.gov/MPF/roverpwr/power.html
Re:Battery life? (Score:3, Insightful)
Simon.
No. (Score:2)
If a nuclear-powered device explodes on launch, or in low orbit, it's "not a good thing". At the very least you'll get radioactive debris spread over a wide area.
You actually think NASA would be dumb enough to send up a nuclear-powered device without adequate containment against explosion and re-entry?
NASA may be huge, inefficient, wasteful and sluggish, but they're not stupid.
Re:What has changed since 1970's? (Score:2)
Re:What has changed since 1970's? (Score:2)
Re:What has changed since 1970's? (Score:2)
Re:What has changed since 1970's? (Score:2)
Re:What has changed since 1970's? (Score:3, Informative)
Radioisotope Thermoelectric Generators (RTG's)
Three RTG's provide electric power to Voyager. The generators produce about 1800 watts of heat by the radioactive decay of plutonium. The heat is then converted to about 400 watts of electric power by thermocouplers. The RTG's are mounted on a boom to protect the scientific instruments from excess heat and radioactivity.
and this [nasa.gov], which discusses RTGs in the context of Cassini and safety.
Re:What has changed since 1970's? (Score:2)
I'm sure it must be mentioned elsewhere, but I don't see it... It isn't an issue of the half life of the element, but rather the lifespan of the thermocouples. The half life of plutonium could probably power this craft for quite a few years past 2020. The thermocouples, however, have a known degradation rate and therefore their failure rate (or point at which their power production falls below that required to run the craft) is known and can be fixed at 2020. (Roughly, at least.)
Nasa Scientists are ignorant. (Score:2)
I dont care how many degrees you have, anyone ignorant enough to put pictures of us, our DNA, our sound files and everything into space deserves to have their asses kicked.
Its as stupid as me posting my social security number on slashdot, Here 002-32-4840
Here you go, please hiijack my identity, heres my credit card number too! James Spencer 220345035212
Solar Power Not Usable For "Deep Space Probes" (Score:2)
Lets say that the power collected from standard set of solar panels for an object around Earth is suffient to power the electrontrics. The problem is space is big...really big! For instance...
Mars is about 1.5 times as far from the Sun as Earth....
Jupiter is about 5.25 times as far away...
Saturn is about 9.5 times as far away...
I won't go farther.
Of course the idea of radio active material on space probes sends some people into a fit but it really isn't that much material. It also ignores the fact that if we want to do distant science there is no better powersource built yet.
Re:Voy 1 will likely confuse even modern earthling (Score:2)
Ohh, that's what it means. I understood the whole sentence as the origin of this confusion. IMHO, the whole article was confusing, not the data in voyager.
Re:The one problem I have... (Score:2)
I guess part of the reason for AU is to give the man in the street something to understand in news stories (since so many people *don't* understand light years). I doubt anyone really does any calculation with it.
Useful purpose for 1 AU (Score:2, Informative)
First, as has already been pointed out in other replies, miles are also an absurd, arbitrary unit as far as science is concerned. We could get a 'round' unit if we took, say, about .65 AU, as the 'new' astronomical unit--exactly 10^11 m.
But then the AU would be a pretty useless yardstick. Earth's orbit is very nearly circular, which means that over a period of six months, the Earth moves a net distance of (almost) exactly 2 AU. Using this knowledge, it is possible to measure the distance to nearer stars. As the position of earth changes, the apparent positions of nearby stars will also appear to change relative to much more distant stars--a parallax effect. To get a precise measure of this distance, you want to move the Earth as far as possible, to get the maximum apparent shift in position. 2 AU is as far as we can readily move the earth.
There is even a unit of measure that is defined on this basis. The distance at which the apparent parallax shift of a star is equal to one second of arc is defined as one parsec. Parsec measures can be directly obtained from astronomical images taken six months apart, so they are the preferred unit of measure for some types of observational astronomy.
Of course, this also works backwards. If we could see a planet orbiting a star one parsec away (about 3.26 light years--this is a hypothetical case) and its orbital motion was across one apparent second of arc, we would know it orbited its sun at a distance of 1 AU.
Re:The one problem I have... (Score:2)
1) Why apply a conversion factor just to express it in meters?
2) The proper conversion factor depends on other measurements (I'm actually not sure how the mean earth-solar distance would be measured), so it can't be defined arbitrarily. If you made the Earth 0.93 AU, you'd have to multiply all your parallax measurements by 0.93 to get the distance in your "new AU" anyway. Pointless effort for no gain.
There is a reason for proliferation of auxiliary units. The interatomic spacing of Si atoms in a crystal is used as a basis for diffraction measurements; the "amu" is the basis for atomic mass measurements; the "mol" is used as a measure of quantity, etc.
In all of these cases, the measurements based on the unit are more (or just slightly less) precise than the basic unit can be measured by other techniques. It is most convenient to express your results that best preserves the original accuracy.
What the hell are we doing this? (Score:2)
What next? Displaying your social security number on the INTERNET? Yeah let all the terrorists and hackers grab your identity?
Well thats what we are doing in space, dumbass Nasa scientists should get their ass kicked seriously.
Re:why give them our DNA? (Score:2)
But thats not DNA! (Score:2)
Radio Signals allows them to know theres something going on at Earth. But they'd have to come here physically to see exactly what we were doing, They'd have to physicially land a ship, get out, snatch a few hundred of us of us from all diffrent races and capture our DNA.
They wouldnt be able to just hiijack our DNA from space, and come to earth looking just like us.
Re:DNA looks o.k. to me... (Score:2)
This would be an interesting experiment to try. Replace the symbols with a consistent set of otherwise meaningless glyphs -- a kind of substitution cipher. Then hand it to a competent biologist and see how long it takes him to come up with a correct interpretation -- probably not more than a few minutes.
You can make it progressively harder, by eliminating certain assumptions about how to represent certain things. For example, you could replace the lines used to indicate chemical bonds with dots; 1 dot for a single bond, 2 for a double, three for a tripple. Also, the alternating 1/2 bond representation of carbon rings is a bit arbitrary; another symbol might be better to represent the nature of the bonds within the ring.
Nonetheless, when looked at by a person who studies organic chemistry, I don't think it would take long for him to figure out.
I think it is very likely that any intelligent life form which encounters Voyager is going to be carbon based; if the civilization has the technology to recover Voyager, it will no doubt have organic chemists. What it will tell them is that we, like they, are carbon based life forms. The exact function of DNA may take them some time to work out, and they may never be sure, but there is a good chance that somebody will conjecture that this is the mechanism by which our genetic inheritance is transferred (assuming they die and leave offspring!). It's a plausible guess, given that if you wanted to give a chemical picture of yourself, the mechanism of genetics would be a high priority.
Re:DNA looks o.k. to me... (Score:2)
It is a bit arbitrary, but it would be difficult accurately to depict the real nature of the bonding in a fused heterocyclic aromatic system in any simple way. A common convention is to draw a six-electron aromatic ring (e.g. benzene, thiophene, tropylium) with a circle in the center. One organic chemistry text, March's _Advanced Organic Chemistry_, adopts this convention for single rings but does _not_ use it for fused systems, for a good reason: if you drew (say) naphthalene with a circle in the center of each ring, you would inaccurately give the impression that napthalene was a system of two independent six-electron rings, and not a fused system of ten electrons with a certain amount of bond fixation.
hyacinthus.
Re:Welcome Who? (Score:2)