Slashdot Mirror
Mapping Gravity
overThruster writes: "No, you don't need to drink the water... Gravity is less strong in India--enough so that you weigh almost 1% less there. See BBC story about NASA's gravity map." Here's another story about the mission, and the GRACE home page (or NASA's less-informative page).
So does that mean that it's cheaper to ship things to India, since when they get there they weigh less?
.99 tons of a thing?
If I shipped a ton of something over there, does that mean that when it gets there, it's only
Earth is cheating UPS/Fedex/whatever shipping agency out of their fees...
1% of 500lbs is...
and I notice a picture towards the bottom. A guy is throwing a ball up into the air and the caption reads "Nasa's Michael Watkins: A new map every month." What does that picture have to do with anything?
That's so racist, but that's funny. India's not a place I'd care to go to eat, that's for sure. I hate curry, too.
I was poking around in all of the sites for a few minutes before I found out that the satellites haven't been launched, and aren't scheduled to go up until Feb 2002. The BBC says it's going to be just a few weeks, but the official site says 97 days.
Interesting note from their site: A secondary experiment that GRACE will perform is to examine how the atmosphere affects signals from the Global Possioning Satellites (GPS). Ahhh, another Slashdot hotbutton! This project just keeps looking better and better the more you check it out.
What's your damage, Heather?
This was Astronomy Picture of the Day last week.
Plenty of depth/background available from there, as always!
"If you create user accounts, by default, they will have an account type of Administrator with no password." KB Q293834
Does this explain why I lost 2 centimetres after moving to Australia five years ago? Went to a medical the other day and the shrinkage was quite unexpected...
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curry is good. so is Chinese, as long as it's not Sesame Dog
Mapping the geoid is one of the most fundamental problems in oceanography. Ocean currents are all basically caused by water running downhill. The problem is that "downhill" in this case is relative to the geoid, which is a bumpy, not-nice surface. With this kind of map, we should be able to map surface currents from space; their velocity, their position, everything you want to know about how the surface currents are moving. This is important for climate studies of global warming, since the ocean currents are one of the main transporters of heat from the equator to the poles. This will allow us to get a much better idea of where the heat in the world is going, and how long it takes to get there, which in turn will give us a better handle on global warming.
Oceanographers have been trying to figure out a way to remove the geoid from their equations for a hundred years. Now we can just measure the damn thing. Crazy.
"The contents of this package are shipped by weight, not volume. Some settling may have occured."
:)
They're consistently defrauding India. Honeycomb's big (yeah yeah yeah) but it's not quite AS big in India? Sue sue sue!
Especially my brother, he needs to lose some weight..heh... just ship him off to India... heh...
If one believes the theory of an asteroid destroying the dinosaurs, wouldn't we see a detectable gravity differential wherever such supposed asteroid hit? Anyone know if that particular theory about the dinosaurs has pointed the supposed impact in India?
Judging by your sig you hate anything but hamburgers and hot dogs. And most likely you have never been out of the good 'ol U.S of A.
:wq
Hell, in my physics classroom it's about 30% as strong as anywhere else. I proved it myself in a lab last week- it's about 3.2 m/s^2 in our corner of the room!
Strangely enough, it's just about 9.8 up front. I guess the earth is pretty aspherical.
-Toad
--
- It ain't easy, being green.
So if things weigh less in India, wouldn't launching rockets and shuttles from there be easier? A 500,000-pound rocket would only weigh 495,000 in India - not a huge savings overall, but you could reduce fuel consumption and save money or go a bit further on the same amount of fuel. And the location is about as far south as Florida, so that's enough planetary curve for them. Should we expect to see more US companies building launch facilities in SE Asia after this report has been out a while?
== Paul Rickard, Editor of The Microsoft Boycott Campaign ====
cannot make me *taller*.
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enough so that you weigh almost 1% less there
Here's a little food for thought though:
"Even a fat bastard on the moon still looks like a fat bastard"
:)
Relations between the two countries are tenuous at best. However, both sides are currently working towards some form of temporary ceasefire over Kashmir. The possibilty of the Indian government permitting foreign launch stations on their soil would be counterproductive, and therefore out of the question.
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...but you'd weigh more when you got back! It's a proven fact that, among other things, the metabolism slows down in low-gravity environments.
--
erik
THE GOOD HUMOR MAN CAN ONLY BE PUSHED SO FAR
Bart Simpson on chalkboard in episode 2F18
...the fact that moving at speeds approaching the speed of light will cause you to move faster through time, so that if you left Earth, travelled at near light speeds, and then came back shortly afterwards, 100 years might have elapsed on Earth in what you perceived as about 10 minutes.
I think that physical laws like this have a very significant effect on the lumpiness of the Earth, and therefore, on the variations in gravitational pull.
Imagine that you're running down a square field, from one side to the side parallel to it, and it takes you 10 minutes to run across this field. Ok, now imagine that you're running across the same field, but instead of running "straight," you're running at an angle, so that you're not perpendicular to the edges of the field that you're running from and to. It will take you a bit longer to get to the other side of the field, even though you're running at the same speed, because by going at an angle, you've increased the distance you have to go to get from one edge to the other.
Now suppose we call the field a 2-dimensional surface, like a piece of paper. You could say that the first time you ran across the field, you travelled along one axis, or dimension--let's say the X axis. But on the way back, you ran at an angle, which means that you've gone along two axes, the X and Y axes. But you went the same speed. This means that you have split the same speed across two dimensions.
We say that time is a fourth dimension. Now picture this: No matter what's happening, you're ALWAYS moving through the 4 axes (the three "space" dimensions and the one "time" dimension) at exactly the speed of light. It's just that you're splitting that speed (the speed of light) across some combination of the 4 dimensions. You're doing one of the following:
I think all of these physical laws have a very significant effect on the lumpiness of the Earth, and therefore, on the variations in gravitational pull.
And, of course, the obligatory OH WELL.
Is that why those people stand on their heads over there? You see all of these Hindu guys doing handstands for days and the like... I knew there was I reason I can't do a handstand. Damn that unfair gravity!
Um, this is my sig.
Thats how they faked the moon landing. They just went over to India and set up shop. They didnt need any wires pulling up the astronauts up, its was all 'real'. btw, I guess all the stuff i learned in physics 101 needs to be recalculated since the gravity isnt 9.81 anymore.
Big deal, you say? Think of the existing physical infrastructure in a city. Now think of a new development that has to tie into the existing water, sewer, storm drainage and roadway systems. If you use GPS and don't take these things into account, you're going to take a chance on sewers that don't drain, storm drainage forming lakes and a general mess (not to mention lawsuits).
Not the typical
Bleh!
You probably hear the 9.8 m/s^2 acceleration due to gravity touted but this is just the net affect across the whole of the globe which is actually very inaccurate when used at specific locations.
Did you know that its actually easier to break the force of gravity ontop of mount everest. I'll show it using the formula:
g = G*(m/r^2)
= ((6.67*10^-11)*(5.98*10^24))/(6.389*10^6)
= 9.77 m/s^2
The value of g also can vary locally on the surface because of the presence of irregularities and rocks of different densities. Such variations in g also known as 'gravity anomilies'. Mineral deposits, for example, have a greater density than surrounding material; because of the greater mass in a given volume g can have a greater value on top of such a deposit then at its sides.
Overall altitude, underground minerals and distance from the equator all play apart in changing the acceleration due to gravity across the globe.
Is it possible that gravity can increase over the lifespan of a planet? I read recently
that 50,000 tons of space dust fall on the earth every day.
Maybe in the time of dinosaurs the earth actually had lighter gravity. Let's see-
50,000 tons of dust X 50 million years = 2,500,000,000,000 (that's 2 trillion tons of dust) that would be enough to effect gravity wouldn't it.
I'm sure my math is off, and that the earth must also lose a fair amount of matter via outgassing etc- But it would explain why such impossible beasts like the brontosaurus were
able to stand under their own weight.
I have no pants and I must scream
...when you think about it. But that's another topic. You want a demonstration of force, try the weak nuclear force. When you drop a ball of off a building, it accelerates (~9.8M/s/s) but when it encounters a weak nuclear force (the atoms in the 'ground' where it 'hits') it effectively 'stops'
;)
In other words, it's not the fall that kills you, it's that sudden stop at the end
Gravity smavity... let's investigate something interesting
(in all fairness, my buddy's father is a nuclear scientist who holds the current best measurement for Big G, but I still can't believe it's a 'force' per se)
"Whoever would overthrow the liberty of a nation must begin by subduing the freeness of speech."--Benjamin Franklin
Hey Anon DW
:-)
I wasn't lying. I really shrunk two cms. vertically, and I attribute it to stronger magnetic forces [plus weak bones].
About the nick - it's a wordplay on Compact Disk, but surely biases the moderators as me being a troll. Ah well - like Soko says, it's only Karma
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The problem is, and of course the word 'relativity' is supposed to clue you in to this, is that the Earth is also moving away from you at near light speeds. So, 100 years might elapse for you while on Earth they only perceive 10 minutes.
Tricky shit.
Endless arguments over trivial contradictions in books written by ignorant savages to explain thunder in the dark.
Quoth Dr. Whitehouse: [...] should add a new dimension to our understanding of our planet.
Aha! I knew there was a catch.
because there is less gravity
gravity
n 1: the force of attraction between all masses in the universe;
especially the attraction of the earth's mass for bodies
near its surface; "gravitation cannot be held
responsible for people falling in love"--Albert Einstein
[syn: {gravitation}, {gravitational attraction}, {gravitational
force}]
Well that explains the bed of nails.
"Gravity is less strong in India". Less strong than where? I know it's too hard to become less US-centric, but you could at least mention "less strong than in the States".
Indian Curry = Hotter than the sun's corona.
Indian Water = Makes Montezuma's Revenge look like a christmas present.
Good luck gaining weight in India, slow metabolism or not.
Just wait until Bin Laden decides to pull off a terrorist attack in your country, then we'll see how you feel about him.
Since I don't have any karma I can't lose it
The worst terrorist attack in recorded history occurred on September 11th, and now we're involved in a WAR against Islam and you people have the gall to be discussing mapping gravity????
Yes, we have the gall.
Ask NAVO (the Naval Oceanographic Office) just how much gall they have, mapping gravity over the surface of the seas! In the Old Days, before nifty toys like Satellite Gravity, we used to grid the earth's field by taking in situ measurements all over; *much* of which was done by oceanographic research vessels
Now, a good portion of that gravity grid was done for nice oceanographic or geologic reasons; if you know the density of the stuff below you, you can get a pretty good guess at the shape and contents of the seafloor below, but curiously, the more sensitive and more accurate gravity meters were owned and operated by the USN.
Why is that? Because a good map of the gravity patterns of the sea floor can help with navigating around it, when you *haven't* the luxuries of GPS or loran or other positioning systems.
Submarines!
Gravity maps done by NAVO ships in the Indian Ocean (which have greater detail and precision than the NASA maps, even if they are much narrower and smaller region of coverage) are quite possibly as we speak, helping guide USN subs in the vicinity, as they prepare for any lurking regional threats.
For a quick glimpse of grav fluctuations in the south pacific, as recorded on a Navy Gravimeter (aboard a civilian research ship) try at the bottom
Anyway, most everyone in the Oceanographic community is really excited about satellite gravity, since its coverage is just about universal (except for the poles) but we still lug out the Bell Aerospace meters (ugly black things) from port to port.
If anyone were interested, I could post descriptions of how some or any of these things work, except this is slashdot and this post will probably end up as (Score:-1, TrollFood)
First, nothing begins if not opening
How does the military deal with changes in the force of gravity due to altitude and location? A 1% change in gravity is a big deal if you are firing an artillery shell at a target over a long distance. I was watching a documentary on the ENIAC computer and it said the computer's primary task was to calculate gunnery tables for the military. Wouldn't all of those carefully calculated tables be useless if the force of gravity changed?
Mea navis aericumbens anguillis abundat
A new gravity map of the Earth suggests that if you want to lose weight you should go to India, where the pull of gravity is slightly less than it is elsewhere on the planet.
Since you weight less, wouldn't you be expending less energy when you move, and therefore get less excercise, and therefore get fatter?
I'd crashed on my bike (again - don't ask), and was being checked by a nurse. A kid is lying in a bed a few meters away, with both arms and legs in casts. He had a conversation with a passing nurse. It went something like this:
Her: "What happened to you?"
Him: "I fell out a window."
Her: "How far up were you?"
Him: "2nd floor."
Her: "It must have hurt a lot falling out the window."
Him: "No - didn't hurt at all."
Her: "Oh come now. You've broken your arms and legs. It must've hurt a lot."
Him: "No, it didn't hurt falling out the windows. The landing was a bit tricky though."
I couldn't help but laughing out really loud, cause the kid couldn't have been more than 10 or 11, and he showed both a very good sence of humour and a fairly precise knowledge of how to use the language.
The nurses of course couldn't see the humour in his joke, and didn't think I was very polite by laughing at the kid. Grown-ups.
When I grow up, I want to be a child.
We do not live in the 21st century. We live in the 20 second century.
...Gravity is less strong in India...
So *this* explains the Indian Rope Trick!
:-)
It's huge. It's only hidden because it's under water. Check here for pictures of said hole in the ground.
Whats does "neoron's" mean?
Surely you mean 'the worst non-government terrorist attack'? Humor me. I don't want to go googling for all the easily verifyable evidence.
Seems to be a bit of duplication going on - ESA are running a similar experiment with their more clumsily acronymed GOCE satellite:
e _0 .html
http://www.esa.int/export/esaLP/ESAYEK1VMOC_goc
Sorry. Couldn't resist...
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
Well, that finally explains the magic carpet thing...
Skiers and Riders -- http://www.snowjournal.com
Good explanation. Thanks!
;-)
Two more things though.
1) The gravity field of the oceans can be mapped from space by using satellite radar altimetry. One Navy satellite especially launched for this was GEOSAT. The detailed altimetry data from this mission was long classified, until equivalent data became available from the ERS-1 mission...
It works by mapping the precise shape of the ocean surface from space, from a known orbit. Assuming that the ocean surface is in hydrostatic equilibrium, this gives you the geoid ("mean sea level"). The assumption is wrong, of course, which is where the "real" satellite gravity missions -- and in-situ measurements -- come in.
2) The reason the Navy wants to have the precise gravity field is not only to be able to use inertial navigation themselves (for the submarines), but also, and especially, to know the direction of the vertical at the precise location where those Poseidon missiles take off. They too use inertial guidance, and the platform aligns with local gravity before launch! If they take off in a direction that is 5'' wrong, due to an erroneous local vertical deflection, that translates into a 150 m targeting error at 6000 km.
For some reason this is not considered good enough
Anyone ever heard of the theory that gravity was a push and not a pull?
Maybe india is just less pushy then the rest of
the planet.
The problem as I see it is that I have no personality of my own.
Decimal is for superstitious idiots. Use hexadecimal if you want to describe the world.
I couldn't help but laughing out really loud, cause the kid couldn't have been more than 10 or 11, and he showed both a very good sence of humour and a fairly precise knowledge of how to use the language.
And apparently had already had enough of the stupid people around him, and decided to end it all, unfortunately (for him), 2 stories wasn't enough to do it.
Back in 1978, Arthur C. Clarke ended his book The View from Serendip by writing about a gravitational anomaly which was found off the coast of Sri Lanka (formerly Ceylon) -- the small island near India where he lives.
I am able to visit my favorite spot (Chapter 13) for only a few days a year. But now, quite unexpectedly -- and literally since I wrote the preceding paragraph! -- Serendipity has struck again. While researching a totally different subject, I've discovered a good reason for spending more time on the south coast.
It concerns the greak Sanskrit epic, the Ramayana. In this 2,200-year-old poem, the demon-king Ravanna kidnaps Sita, wife of Rama, and takes her to his island stronghold of Ceylon. Needless to say, she is ultimately released, after aerial battles involving what look suspiciously like atomic weapons and laser beams.
To heal the wounded, the heroic monkey-general Hanuman is later sent back to India to fetch a medicinal herb found only in the Himalayas. Unfortunately, when he gets to the right mountain he is unable to identify the herb. No problem; he brings the whole mountain back! However, one piece drops off, on the southern tip of Ceylon. The locals believe this fragment is in fact my favourite bay, for its name in Sinhalese means "there it fell down" (onna watuna).
There it fell down. Place names usually have a meaning, though it is often lost in the mists of time. Did something really fall down, centuries or millennia ago, at Unawatuna Bay? A meteorite would be the obvious explanation; it must have been a big one for the legend to have lasted down the ages.
And here's another weird coincidence. Little Unawatuna, believe it or not, is the closest point on dry land to the world's greatest gravitational anomaly, a few hundred kilometres out in the Indian Ocean. On the Goddard Space Flight Center's 3-D map of the Earth's Gravimetric Geoid, that strange phenomenon looks liek a deep pit [1] into which the whole island of Sri Lanka is about to slide.
Let's put two and two together. A few thousand years ago, a huge object of peculiar density plunged into the Indian Ocean, creating a tradition that is remembered to this day. And it's still there, distorting the earth's gravitational field -- Terran Gravitational Anomaly I.
That might make an opening for a pretty good science-fiction movie . . . and an even better ending for this book.
Ayu Bowan.
1. One hundred and ten metres below zero reference on the Goddard model (March & Vincent, 1974).
There's quite a large bulge of ocean that trails the moon around the earth, and a similar bulge diametrically opposite to it. There's a smaller bulge due to sun tides.
The GRACE home page doesn't seem to mention the effects of tides. Doesn't all that moving mass of H2O change the planet's mass distribution enough to mess with gravimetric readings?
(Disclaimer: I am not an earth scientist.)
The gravity map has been prepared to help scientists plan the forthcoming Grace (Gravity Recovery And Climatic Experiment) satellites, to be launched in a few weeks. - BBC News Article.
... is it just me or did anyone else misread that as "Gravity Recovery and Climactic Experiment"?
we all know things weigh less in india, but we thought its because everyone was starving.
Reason, free market capitalism, and individualism
Actually, it's not quite so simple. From the equations of special relativity, one can determine that the following are true:
1. If an object travels at a speed less than that of light, it must have real mass.
2. If an object travels at the speed of light, it must have no mass.
3. If an object travels at a speed greater than that of light, something bizarre happens. If such an object has real energy, it will have imaginary mass. If it has imaginary energy, it will have real mass.
Ok, so you want to go faster than light. You probably don't want to turn into imaginary matter, so you're going to have to find some imaginary energy.
If you find some, let me know.
IANAScientist, but I understand that the earth bulges at the center due to the centrifugal (or is it centripetal) force caused by its rotation.
Wouldnt this same force make you weigh less close to the equator and more at the poles?
Just curious.
I couldn't fail to disagree with you less.
I just can't keep all those bosons and their quarks straight !
Here are a couple links about measuring Big G (Luther and Towler):
An entertaining mix of real science and Star Trek
The Controversy over Newton's Gravitational Constant
Enjoy !
"Whoever would overthrow the liberty of a nation must begin by subduing the freeness of speech."--Benjamin Franklin
Gravity is Not really a force ;)
I guess it matters relative to (no pun intended) if you are looking at the questions as Newton or Einstein.
"Gravity is the result of four-dimensional space-time being warped by the presence of mass"
consider this, "We constantly fall back on the belief that gravity is a force even when we know otherwise"
And from the WhyFiles,The six-minute guide to space-time, "Einstein concluded that gravity was a property of space-time, not a separate force."
"Whoever would overthrow the liberty of a nation must begin by subduing the freeness of speech."--Benjamin Franklin
I love this theory. Much more believable than that very ignorant Pangea theory.
. ht m
:/
http://www.dinox.freeserve.co.uk/english/exlink
Too bad the pages are missing so much other relevant data and have other inaccuracies. (Like their total exclusion of how much mass the earth gains every second of every day. How much mass per day did the earth gain 100 million years ago? 3 billion years ago?)
50,000 tons of dust does not even include the tons of water we also accumulate each day.
Too bad humanity is completely consumed with selling each other worthless crap instead of devoting itself entirely to science, philosophy, and becoming more than the destructive, murdering, imbeciles that we are...
Observe Buy NOTHING Day (Nov. 23)
http://www.adbusters.org/campaigns/bnd/
http://en.wikipedia.org/wiki/2004_U.S._Election_c
The heat from the sun
The gravity of the moon
The internal heat from the Earth
The rotation of the Earth
and Fish Farts
http://en.wikipedia.org/wiki/2004_U.S._Election_c
You're not too far off the mark when you write the photons would have to bounce around. That's pretty close to the truth. The photons interact with the material.
However, it's not like a billiard ball bouncing around a table or trying to walk through syrup or any other common-place analogy. Even the idea of a photon moving is a bit illusory. There's no way to watch a photon move. If you've seen a photon, it's already not there any more.
This only starts to make sense when you think in terms of quantum electrodynamics (QED). There is no basic law of physics that says that a photon has to travel a straight line (or a geodesic, as in General Relativity). What QED uses is a thing called an amplitude, which underlies every particle in the universe. You can think of an amplitude as a little watch with a sweep second hand going around with the frequency of the photon and moving at the speed of light. However, all you can observe is where the photon leaves and where it winds up.
Where the photon actually winds up is determined by figuring out the amplitudes for all possible paths and summing them up using vector arithmetic. This gives a single vector. The probability of the photon winding up there is proportional to the length of this vector squared. Light travels normally in a straight line because this is where all the local amplitudes reinforce each other by summing up, while elsewhere they tend to cancel out.
This is obviously a lot of paths, and it's hard to do. It wasn't until the late 1940's that the math was solved. It's still hard to do in complex situations, even with computers.
This seems weird, but it explains the workings basically of everything in the universe outside the nucleus. How light bounces off a mirror, how parital reflection works, diffusion, why light goes the way it does in GR, the color of white paper, everything. (The same quantum rules work for solid matter, but it's just easier to understand with light.) The wave theory of light does not explain its behavior fully (it works pretty well until you get to multiple sources and detectors), nor does a more classical particle theory. I don't know if someone will come up with a different theory, but if they do, I'm pretty sure it would be just as weird.
For inside the nucleus, people are working on quantum chromadynamics. I did some visualization work on that a few years ago, but I don't know the status today.
In transparent materials, light looks as if it had moved in a straight line at a slower speed, but it really doesn't. The amplitudes suggest a path of highest probability that is not in a straight line.
Why does it come out in a straight line? Well, it doesn't always! If you sandblast glass, much more is reflected, and it's all scattered about. Note that this does not make sense with classical theory: you might guess that the irregular surfaces did scattering, but you wouldn't be able to guess that more would be reflected back. However, well polished glass is uniform enough, at least with respect to the wavelength of the photon (which is, for visible light, much bigger than the atoms), any net effect at deflection cancels out.
Change the wavelength of the photon and the situation changes, which is why prisms and X-rays work the way they do. Change the way the material is packed, and it also changes, which is why graphite is opaque and black while diamond is transparent.
Incidentally, this also happens in a vacuum, because there are virtual particles in the vacuum. Not many, but enough to have a tiny effect. You can get rid of most of these virtual particles by putting two plates so close together that there isn't enough room for them to form. Then light appears to go a teensy bit faster, though not enough to worry about. It's that maximum speed that is the thing.
I hope this handwaving is an improvement.
Please living in glass houses should not throw stones at others
It's 1% weaker then where?
/.Mattsson - My native language is not English, so please don't whine over linguistic errors. (That's lame anyway...)
Every Book about relativity written mentions the observered effects of length contraction and time dialation due to near-light speeds, as radar-effect, which can be compensated for light rays coming form a farther distance. Which morons gave them their PHDs. They accept gravity as space warp and use newtons G constant in relativistic equations !!
Excuse me, but what the fucks a "neoron"?
que pasa?
--
"I feel so cold, on hookers and gin... this mess we're in"
So if they are poor in india and are slowly starving when they actually have a "kind of stable" government, then they would be even "skinnier" and more "starved" in the "Himalayas", and with the added "lightness" of "mountains", I think I may "understand" how those "buddha" fellas in "Tibet" can "levitate" themselves... they're just "jumping"!
Don't you hate people who always "quote unquote" things? Its especially hard to do the " " finger thing when you're typing at the same time...
--
"I feel so cold, on hookers and gin... this mess we're in"
okay, methinks someone needs to settle down and go find a prostitute... or if you can't afford that then buy yerself a porno and invite yer friends mum over to read it with you (believe me, it works and you will soon forget about any war... not that I know what war you're on about... please reply with everything that happened on sept. 11th, kay?).
--
"I feel so cold, on hookers and gin... this mess we're in"
well obviously all those starving indians only LOOK starving
If you are observing yourself, then your rate of movement through time is 1, with no units. If you are observing something else, then its rate of movement through time is dT(it)/dT(you), which also has no units, but is not necessarily 1. So if you observe something moving at .85c, it is moving through time at a speed of 1/2 (relative to you).
You can't move through time at the speed of light, because c is in units of distance/time. You can just pick a system of units such that c is 1 distance/time, instead of 3x10^8.
There are few pseudo-sciences as well entrenched as Astrology. Every once in a while somebody tries to rationalize the effects of Astrology as an actual gravitational effect of the planetary alignments that has a slight but important effect on world affairs and on individual people's destiny. The problem with this is, that there are so many other variations in the Earth's gravitational field that no such effect could get through the background noise. As a geophysicist, I've used measurements of the variations in the local gravitational field to model underground structures, ranging in size from the Rio Grande Rift in New Mexico, to small landfills and service tunnels on the campus of UT Dallas. We never correct for planetary gravity. In fact, when doing gravity measurements in the field, you have to make sure to park the truck a few yards away from where you take your measurement, because an SUV has enough mass to mess up your reading. The mass of Mars, or even Jupiter is very large, but so far away that the SUV a few feet away has several orders of magnitude more influence.
Astrology doesn't work through any physical medium.
if ($it != $onething) {$it = $another;}