Yeah, it's about 530,000 pixels away, kind of shows the grand scale of our solar system and that's just the parts have have a chance of reaching any time soon.
You can easily build an in 1:2e9 scale replica of the Solar System. You'll just need a 90cm sphere to use as the Sun, some 4-5 km of area do arrange things and a paquimeter for measuring the planets. At this scale, everything is just about as big/small as one can manipulate.
Bu you won't be able to place the Voyager in there. For that you'll need a car and a road trip.
The one close to me is in Helsinki-Espoo:
http://www.waymarking.com/waymarks/WM8AJ4_Ursa_Model_of_the_...
But this one's slightly bigger, scale is o to billion. You can still see the Sun from Neptune, if you have binoculars (4487 meters, the Sun is 140cm in diameter).
Shouldn't it be something more like 20,000 km, since the equator is about 40,000 km long and we're looking at half of it? Anyway 6,371 can't be right though.
No, that's circumference - 3.14 * 12742 is approx. 40K.
You are looking at the Earth side-on, so you only see the 2D projection of the half-equator. (EDIT: I think it should be "1D projection")
Another nitpick - presumably our view axis is perpendicular to the solar system plane. The Earth would not look like in the picture, we would see one of the poles but slightly off-centered.
You're right! How frustrating. The most frustrating is that I was just about to share this with some friends and know that I now risk either: 1.) Them smugly pointing that inaccuracy out and failing to enjoy how cool this is otherwise, or 2.) The website author correcting it by the time my friends see the link so any "btw there's a typo" comment I make being confusing. I'm going to share it anyway!
EDIT: I fear this may be worse than we had initially thought. The diameters of the Moon and Mars suffer the same problem and the pixel distances appear to be based on those wrong numbers so actually all the "apparent" distances are twice as long as they should be. (My working was to check that the Earth was indeed 100 pixels on my screen, calculate that 1 pixel = 127.42km, multiply that by the claimed "6033 pixels" to the moon to get 768724.86 which is twice as large as it should be...)
No. Simply put: the core is likely solidified just like Mars and its magnetic field is very weak, causing the weather to be influenced by only its rotation and solar winds. It would be far more difficult to terraform than Mars really.
Also a Venusian day is something like 5,800 hours and its surface temperature is capable of melting lead.
I offered a guess as to how/why someone might think the core is solid, not an argument for that conclusion. I included an easily digestible article which touches on all the same theory as the Wikipedia entry which was posted in "response" to it.
Not all Internet communication has to be quippy argument.
Also, the context of that citation:
"By analogy with Earth, the core of Venus is at least partly liquid because the surface-to-volume ratios of the two planets in Figure 10.5 are virtually identical, which implies that they have been cooling at about the rate. If the core of Venus is at least partly liquid, then Venus should have a magnetic field similar in strength to the magnetic field of Earth as discussed in Section 6.4.5 and in Science Briefs 6.7.3,4,5,6 and 7. However, the Mariner 2 spacecraft determined during a flyby on December 14 of 1962 that Venus does not have a planetary magnetic field."
The book goes on to cover various theories about the absence of a magnetic field identifying a solid core as "not credible", slow rotation of Venus failing to activate convection currents as "possible", lack of a solid inner core due due to pressure (questionable) and temporary decay of the field (questionable).
I like to believe we could circumvent some of these problems technologically. After all, there is no particular reason to feel bad about macroscopic terraforming on a lifeless planet. Yes, it would be more work than Mars. But it's also bigger than Mars and further from the asteroid belt. No planet but Earth is going to be ideal.
The amount of energy you'd have to expend to fix Venus would be far more costly than trying to keep Mars warm by using baseboard heaters on every square metre.
One of the largest issues facing Venus is that it is effectively a dead planet. Mars is a dead planet too but it's far easier to make it warmer than to cool down Venus so we can live on it. On top of that, Mars has water frozen at its surface and perhaps in liquid form beneath; Venus only has water vapour that accounts for less than 0.01% of the total atmospheric make up.
And if it is size that you want to take into account, then think about this: it's far easier to fix a smaller planet that is geologically dead than it is a planet of our size.
Venus is never going to be colonised. Mars maybe not, but at least that is less of an impossibility.
I appreciate your taking the time to reply, but I think it's a little soon to be saying never. For one thing, we have spent a lot more time and energy trying to figure out what's going on with Mars than Venus.
Though of course Mars is a better prospect today. Frankly, I think the important thing is to have a backup, as it were, and to that end whatever serves will do. But if one backup is nice, two is even better, and the cost of making a good backup is highly justified.
In the case of Venus, the Soviets had sent several probes (Venera) from the 60s into the mid-80s. When the first probes were sent to land on the surface, it was discovered that the atmospheric pressure induced (about 100x the pressure here on Earth at sea level) was crushing the probes before they even touched down.
It took until 1970 for the Soviets to succeed and the landing device lasted a grand total of a half hour once it had landed on the surface. In fact, it barely survived due to the fact that the parachute broke and it ended up hitting the surface at 60 KM/h. It registered CO2 levels of 97% during its descent.
Venera 9 was similar in concept to the Viking landers and landed five years later, but it managed to last for almost an hour before failing due to the immense heat. The longest any Venusian surface programme by the Soviets was just shy of two hours.
Let's compare this to the Americans' probes to Mars: all of them have managed to out-last their stated mission. We have a rover that was intended to do its job within a 90-day period which instead has defied its masters and instead continued on to this very day.
The reason why I completely discount Venus as a place we'll ever visit or colonise for that matter is because it comes down the old principle that I like to follow: it's easier to bundle up than to bundle down. I can put on layers to keep my body heat in, but I cannot do much without expending energy to cool myself down.
I can appreciate that it isn't viable today. But looking back on the history of our species, things that seemed useless or even harmful frequently turned out later to be indispensable resources. Sometimes they did turn out to be simply unhelpful and harmful and I can appreciate that this is the current state of knowledge with Venus, and that it isn't especially economically meaningful to hammer on it further at this time. I just don't think it's safe to consider the matter settled for all time.
Moving to a Mars orbit would have a significant effect on the surface temperature.
More of a problem is the bulk of the atmosphere being carbon dioxide (breathing even a 5% mix is excruciatingly painful for humans), but the real challenge would be dealing with the rains of sulfuric acid... at least Mars wouldn't be trying to dissolve your hermetically sealed environment.
Theoretically, we could build floating cities on Venus:
Landis has proposed aerostat habitats followed by floating cities, based on the concept that breathable air (21:79 Oxygen-Nitrogen mixture) is a lifting gas in the dense carbon dioxide atmosphere, with over 60% of the lifting power that helium has on Earth. In effect, a balloon full of human-breathable air would sustain itself and extra weight (such as a colony) in midair. At an altitude of 50 km above Venusian surface, the environment is the most Earth-like in the solar system – a pressure of approximately 1 bar and temperatures in the 0°C–50°C range.
Because there is not a significant pressure difference between the inside and the outside of the breathable-air balloon, any rips or tears would cause gases to diffuse at normal atmospheric mixing rates rather than an explosive decompression, giving time to repair any such damages. In addition, humans would not require pressurized suits when outside, merely air to breathe, protection from the acidic rain and on some occasions low level protection against heat. Alternatively, two-part domes could contain a lifting gas like hydrogen or helium (extractable from the atmosphere) to allow a higher mass density.
Could make a cool animation showing off the fine structure constant going from classical electron radius to Bohr radius and Compton wavelength. That would be a total zoom factor of 18769 which is about right. The hard part would be designing an infographic to make sense to people who probably don't "get" what the bohr radius is, etc.
Oh this is fantastic! My father teaches astronomy to kids (he has a mobile planetarium that he takes around schools [1]) and one of the main pain points he has mentioned is communicating a sense of scale to them.
This is elegant because it mixes the concept of "imagine this orange is the earth, mars would be in <nearby town>" within the constraints of a web page.
Kids have difficulty visualising distances in an abstract way - but time is much simpler. And the length of the scroll to Mars really emphasises this.
1) 3100 px: Farthest humans have been from Earth (Apollo 13, April '70: 400,171 km)
2) 10 px: Gemini 11, farthest from Earth on non-lunar mission (Sept '66: 1,374.1 km)
3) 3 px: Apogee of ISS (farthest a human has traveled for... a while: 424 km) (I'm probably forgetting something, can't find a good list of spaceflights by distance...)
Taking Earth's diameter as 12,742 km (though it bulges by about 43 km in the center), we're saying that's 100 px. So if my basic algebra is right (no promises) you can convert the above km values to px by dividing by 127.42.
I think the value of this is in its focus and simplicity. There have been other websites using zooms and/or scrolling to visualize scale differences (e.g. http://scaleofuniverse.com/), but this is an elegant statement about just one fact, and I think that's more likely to get the ball rolling in someone's brain and amaze them than inundating them with trivia all at once (but thanks for the trivia just the same :).
Every time I see that page it makes me realise just how small and insignificant we are in the grand scheme of things, and how badly I really want to go exploring everything that is out there.
Yet you could spend an entire lifetime exploring everything that is 'here', and still not manage it.
Space is unfathomably big, and we are a grain of sand on the beach of the universe. But that grain of sand contains enough complexity and variety to fascinate for a practically unlimited period of time.
Mars is cool, and grand, and inconceivably different. I'd rather see the cherry blossoms in Japan, or go for a walk in the outback, or see tierra del fuego (sp?). And really, it's not even just the big things on my (long) list, but the billion other little things that one can do and see on this world given time and resources to wander from place to place exploring and experiencing.
I made a 3D render of a flyby. I should have added markers from the space programs into the video. The video shows how long it would take to reach all the planets, if you flew at a constant velocity (about 10x light speed).
"3) 3 px: Apogee of ISS (farthest a human has traveled for... a while: 424 km) (I'm probably forgetting something, can't find a good list of spaceflights by distance...)"
You're forgetting STS-125, the last Hubble Space Telescope Servicing Mission, March 2009, Apogee 578 Km.
Brilliant. I never actually reached mars - just the gut wrenching distance to the moon made me realise how amazing the Apollo program was - whatever gets us to Mars ...
I'd love to see the Sun included on the opposite side of the scale. Its diameter is 109 times that of earth, making it 10900 pixels. Would be just as impressive a demonstration.
It bothers me a little that they show the motion against a starfield like that -- the stars are so far away that they won't shift perceptibly even on a journey to mars.
I mean, I don't have any better ideas, but given that the whole point is to give an idea of scale I wish they'd come up with something else. :)
You're talking about a first-person view, aren't you? But we don't start with that, we start with a third-person view of Earth and then "pan" across the sky...
So wouldn't panning across the sky from whatever vantage point actually produce that movement? Same as when you point a telescope and pan, the stars move against your view...?
Hmm, I see what you're saying, but that's not what the demo is trying to convey. At one point it says "You're now traveling at [1/5 the speed of light]" -- that would be nonsense if it was conceived as a panning motion.
e: Ah, but as someone else points out, the trip must actually exceed the speed of light, so the whole thing is nonsense. The author should recast things the way you describe them, and thus solve multiple problems at once.
Let's get to the bottom of this. It is a panning motion, this much is physically, visually true. Does it still make sense to talk about 'speed of motion'?
Now I'm confused. What happens when you pan from the moon to the sun (during a new moon, when they're ostensibly both visible)? If you do it quite quickly you are panning faster than the speed of light? (In the interpretatio: 'if a physical object remained at the center of your scope as you panned, and started at the moon, it would have to move faster than the speed of light, to follow your pan?)
So if you pan from one thing to another and they're 1 light-minute away and you take one minute to pan, does it make sense you are 'panning at the speed of light'? For something that leaves one object and goes toward another?
Any comparison to the speed of light immediately invokes other concepts that wouldn't apply to panning, so it's probably a bad idea.
There might be situations where it makes sense to map an angular speed to some sort of absolute speed, but it just doesn't work in this particular example.
The specific situation where it makes sense to map an angular speed to some sort of absolute speed is if you're told - or have some way of figuring out or knowing - the distance of the camera to the two objects (including if it is very highly zoomed, which it obviously is, from the perspective we are shown).
in this sense - if there is an intuitive sense of the distance of the camera and the high level of zoom - it makes sense to speak of an object leaving earth at the velocity that lets it stay in the center of the frame as we pan.
You're right, we do start with a 3rd person view of Earth .. but I still interpreted the motion as translation rather than rotation.
By your interpretation, the camera lens is at a fixed point and then simply "swings" from pointing at Earth to point at Mars. But, from such a supposed point, both the Earth and Mars would be fixed points rather than objects with "multi-pixel" width.
So the fact that both the Earth & Mars are viewable as non-point objects implies translation rather than rotation... and so GP's gripe stands =)
If the camera lens is at a fixed point and then swings from pointing at Earth to pointing at Mars, and we imagine how fast something would have to travel leaving Earth to remain at the center of the camera sensor as it pans - isn't the obvious question "how far away are we??" So it doesn't really work.
It also doesn't work because at different camera locations the Earth and the Mars would have different relative sizes... I suppose we should state that this will be an equilateral triangle formed between the Earth, Mars, and the Camera, the "height" of the equilateral triangle is x, and that Earth will be so many pixels wide on that camera when zoomed 2000x (or whatever).
This interpretation might be specific enough and also match the experience.
1. Choose a position where the proportional sizes of the Earth, Moon and Mars are what they are on the page. This is likely far away above the ecliptic (the plane the planets are in).
2. Choose a telescope focal length to set the right scale for the planets. Ie magnification.
3. Pan and imagine there is an object in the ecliptic plane at the center of your field of view. Mention the calculated speed of the object.
How about you just imagine the ship is rotating on an axis for artificial gravity generation. Then, if you were looking out the window, you would see the starfield whizzing by. :-)
A little bit about the Mediterranean. But not at all to Florida, I think we all would be better off without Florida. (The geniuses that inhabit that peninsula need to go with it.)
I think the best thing to do would be to provide periodic asteroids or rocks that go across the screen every now and then---it's very difficult to get a sense of speed with a repeating star field, not even including the fact that this wouldn't happen in the first place.
Since the starfield was periodic, it looked to me as if it were staying still or moving backwards at times (the wagon-wheel effect[1]) :(
it says it is traveling at 1/10 th of light speed. it takes less than minute to get to Mars in pixels, but from other sources I know it takes 13 minutes for radio signal to get to mars. Something does not play here.
This is at the closest pass, when Mars is ~0.5 AU away from the earth; that's 4 light minutes.
It takes 13 minutes from light to get to Mars from the sun, and I think that'll also work out to be close to the "average" time from Earth to Mars.
In any case, you're right that apparently the demo exceeds the speed of light at some point, because it doesn't last for 4 minutes. Someone else suggests that the motion be interpreted as a fast pan rather than a physical motion, which is how this should have been implemented to not contradict the laws of physics. :)
One thing that's always gotten to me about this distance is what it means for communication latency. Mars is 20 light-minutes away. If we sent colonists, communication would be a 40-minute round trip. No phone calls home, no way to have a chat with friends or loved ones; at best they could send a message, and wait 40 minutes for a reply. That's far away.
Good point. We have so forgotten how bad it used to be, that 40 mins seems so long. Kings weren't able to talk to their ambassadors in 30 mins, not that very long ago.
if we could stretch a stick as long as the distance from earth to mars and use it to tap on mars ground something like a morse code to communicate, would that message be faster than a wifi message traveling at the speed of light?
Does everyone come up with this idea independently, or is someone suggesting it? It's a very common retort to speed-of-light communications, but someone told me about it before I thought of it.
Anyway, your idea wouldn't work. If you press on one end of the stick, it would issue a pressure wave along the length of the stick near the speed of light (depending on its material), so you haven't gained anything.
No I am guilty of having thought about it myself :)
But I would like to know more about these kind of anti-common sense examples regarding this subject.
Do you have a website or some search keyword to suggest?
Thanks
You're talking about using a mechanical compressive wave in a medium to transmit information. Whether the medium is 'air' or 'stick', the rate at which such waves travel is generally called 'the speed of sound in [medium]'.
Wifi signals to Mars travel at the speed of light in a vacuum. This is faster than any mechanical wave because the changing forces of compression between the atoms in the medium must still obey the speed of light.
mechanical compressive wave ,traveling at the speed of sound? Why do u introduce these? What has sound to do with my example? Imagine the stick not tapping on ground but just getting close. to it. Not an audio, but a visual way for the receiver to tell the 2 different singnal states. Then he'd grab his end of the stick and do the same. I am sure what you say is correct by itself but.. it feels there is just something from it that doesn't fit with my example.. Edit: reading again your comment and trying to understand what you say.. if i get it right then it's totally misleading to call it "speed of sound": it should be called speed of mechanical compressive waves
It's nice but his scale is wrong. He states that the Earth is 6371 km large, while in reality, it's twice that, as 6371 km is just the radius of the Earth, and what you really see is its diameter.
Indeed, and it appears that 63.71km per pixel has then been used to calculate the pixel distances to the Moon and to Mars so in fact they are twice as many pixels long as they should be.
This is really cool, though I would like to see a version in higher resolution with some stars. Not oppressively bright stars, just a hint to remind you that there are billions of billions of violent, fiery balls of self-contained exploding gas out there...
If it was a real photograph, I do not think you would see any stars in the frame. The Earth is extremely bright compared to the stars. If the exposure of the film/video (or your eyes) was set to portray the Earth at that brightness, you wouldn't see any stars.
I like the accurate size/distance but it doesn't have to be a photorealistic representation for me. Pure black except for the earth/moon is boring for a desktop background, and stars are pretty ;o)
That's actually a pretty cool photo. I was staring at it, as my new background, and was thinking how amazing it is that their mutual gravitational influence is actually enough to keep the moon in its orbit. I guess I mean it's hard to tell just how massive yet, in contrast, how small something like the earth and moon are. That or it's the half bottle of beer I've had.
You can draw a circle in the palm of your hand, then a smaller circle on the other. Spread your arms out to your side, and that's about the distance from the earth to the moon.
I would get that tattooed if I was into that kind of thing.
I saw a scale model at an exhibit once. I put my hands over the earth and moon, and my wingspan covered it perfectly with both fitting inside my hands comfortable. I thought it was a very interesting way to illustrate it.
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[ 4.0 ms ] story [ 272 ms ] threadYes.
Bu you won't be able to place the Voyager in there. For that you'll need a car and a road trip.
There are a multitude of others all around the world: http://www.waymarking.com/cat/details.aspx?f=1&guid=52fe...
The one close to me is in Helsinki-Espoo: http://www.waymarking.com/waymarks/WM8AJ4_Ursa_Model_of_the_... But this one's slightly bigger, scale is o to billion. You can still see the Sun from Neptune, if you have binoculars (4487 meters, the Sun is 140cm in diameter).
http://www.spottedbylocals.com/zagreb/zagreb-solar-system/
I think the scale is 1 to 1 billion
pics :] https://plus.google.com/photos/106795164119213709932/albums/...
But in the process I came across this: https://en.wikipedia.org/wiki/Solar_System_model
Another nitpick - presumably our view axis is perpendicular to the solar system plane. The Earth would not look like in the picture, we would see one of the poles but slightly off-centered.
EDIT: I fear this may be worse than we had initially thought. The diameters of the Moon and Mars suffer the same problem and the pixel distances appear to be based on those wrong numbers so actually all the "apparent" distances are twice as long as they should be. (My working was to check that the Earth was indeed 100 pixels on my screen, calculate that 1 pixel = 127.42km, multiply that by the claimed "6033 pixels" to the moon to get 768724.86 which is twice as large as it should be...)
Also a Venusian day is something like 5,800 hours and its surface temperature is capable of melting lead.
1: http://www.universetoday.com/36161/core-of-venus/
What I posted above is simply a layman's summary of all the same things cited in your link.
> Like that of Earth, the Venusian core is at least partially liquid because the two planets have been cooling at about the same rate.
I offered a guess as to how/why someone might think the core is solid, not an argument for that conclusion. I included an easily digestible article which touches on all the same theory as the Wikipedia entry which was posted in "response" to it.
Not all Internet communication has to be quippy argument.
Also, the context of that citation:
"By analogy with Earth, the core of Venus is at least partly liquid because the surface-to-volume ratios of the two planets in Figure 10.5 are virtually identical, which implies that they have been cooling at about the rate. If the core of Venus is at least partly liquid, then Venus should have a magnetic field similar in strength to the magnetic field of Earth as discussed in Section 6.4.5 and in Science Briefs 6.7.3,4,5,6 and 7. However, the Mariner 2 spacecraft determined during a flyby on December 14 of 1962 that Venus does not have a planetary magnetic field."
The book goes on to cover various theories about the absence of a magnetic field identifying a solid core as "not credible", slow rotation of Venus failing to activate convection currents as "possible", lack of a solid inner core due due to pressure (questionable) and temporary decay of the field (questionable).
My apologies.
One of the largest issues facing Venus is that it is effectively a dead planet. Mars is a dead planet too but it's far easier to make it warmer than to cool down Venus so we can live on it. On top of that, Mars has water frozen at its surface and perhaps in liquid form beneath; Venus only has water vapour that accounts for less than 0.01% of the total atmospheric make up.
And if it is size that you want to take into account, then think about this: it's far easier to fix a smaller planet that is geologically dead than it is a planet of our size.
Venus is never going to be colonised. Mars maybe not, but at least that is less of an impossibility.
Though of course Mars is a better prospect today. Frankly, I think the important thing is to have a backup, as it were, and to that end whatever serves will do. But if one backup is nice, two is even better, and the cost of making a good backup is highly justified.
It took until 1970 for the Soviets to succeed and the landing device lasted a grand total of a half hour once it had landed on the surface. In fact, it barely survived due to the fact that the parachute broke and it ended up hitting the surface at 60 KM/h. It registered CO2 levels of 97% during its descent.
Venera 9 was similar in concept to the Viking landers and landed five years later, but it managed to last for almost an hour before failing due to the immense heat. The longest any Venusian surface programme by the Soviets was just shy of two hours.
Let's compare this to the Americans' probes to Mars: all of them have managed to out-last their stated mission. We have a rover that was intended to do its job within a 90-day period which instead has defied its masters and instead continued on to this very day.
The reason why I completely discount Venus as a place we'll ever visit or colonise for that matter is because it comes down the old principle that I like to follow: it's easier to bundle up than to bundle down. I can put on layers to keep my body heat in, but I cannot do much without expending energy to cool myself down.
Venus is not a backup.
The period of Venus's rotation is anomalously long, and whatever caused it probably wouldn't have been in effect had it been further out.
More of a problem is the bulk of the atmosphere being carbon dioxide (breathing even a 5% mix is excruciatingly painful for humans), but the real challenge would be dealing with the rains of sulfuric acid... at least Mars wouldn't be trying to dissolve your hermetically sealed environment.
Landis has proposed aerostat habitats followed by floating cities, based on the concept that breathable air (21:79 Oxygen-Nitrogen mixture) is a lifting gas in the dense carbon dioxide atmosphere, with over 60% of the lifting power that helium has on Earth. In effect, a balloon full of human-breathable air would sustain itself and extra weight (such as a colony) in midair. At an altitude of 50 km above Venusian surface, the environment is the most Earth-like in the solar system – a pressure of approximately 1 bar and temperatures in the 0°C–50°C range.
Because there is not a significant pressure difference between the inside and the outside of the breathable-air balloon, any rips or tears would cause gases to diffuse at normal atmospheric mixing rates rather than an explosive decompression, giving time to repair any such damages. In addition, humans would not require pressurized suits when outside, merely air to breathe, protection from the acidic rain and on some occasions low level protection against heat. Alternatively, two-part domes could contain a lifting gas like hydrogen or helium (extractable from the atmosphere) to allow a higher mass density.
http://en.wikipedia.org/wiki/Floating_city_(science_fiction)...
http://en.wikipedia.org/wiki/Colonization_of_Venus#Aerostat_...
I also find it awesome that this man's name is Landis. Only two characters away from Lando (Calrissian), who also lived in a floating city.
Electrons are point-like particles, ignoring their wave characteristics, so don't have a "size" per se.
This is elegant because it mixes the concept of "imagine this orange is the earth, mars would be in <nearby town>" within the constraints of a web page.
Kids have difficulty visualising distances in an abstract way - but time is much simpler. And the length of the scroll to Mars really emphasises this.
Great visualisation.
1. http://www.starlincs.co.uk
1) 3100 px: Farthest humans have been from Earth (Apollo 13, April '70: 400,171 km)
2) 10 px: Gemini 11, farthest from Earth on non-lunar mission (Sept '66: 1,374.1 km)
3) 3 px: Apogee of ISS (farthest a human has traveled for... a while: 424 km) (I'm probably forgetting something, can't find a good list of spaceflights by distance...)
Sources: http://en.wikipedia.org/wiki/List_of_spaceflight_records#Far...
http://en.wikipedia.org/wiki/International_Space_Station
http://en.wikipedia.org/wiki/Earth
Taking Earth's diameter as 12,742 km (though it bulges by about 43 km in the center), we're saying that's 100 px. So if my basic algebra is right (no promises) you can convert the above km values to px by dividing by 127.42.
Space is unfathomably big, and we are a grain of sand on the beach of the universe. But that grain of sand contains enough complexity and variety to fascinate for a practically unlimited period of time.
Mars is cool, and grand, and inconceivably different. I'd rather see the cherry blossoms in Japan, or go for a walk in the outback, or see tierra del fuego (sp?). And really, it's not even just the big things on my (long) list, but the billion other little things that one can do and see on this world given time and resources to wander from place to place exploring and experiencing.
http://www.youtube.com/watch?v=wM0JMaM_tdQ
You're forgetting STS-125, the last Hubble Space Telescope Servicing Mission, March 2009, Apogee 578 Km.
http://www.astro.princeton.edu/universe/
[1]: http://en.wikipedia.org/wiki/Voyager_1
[EDIT] 1000 to 10^10 :P
I mean, I don't have any better ideas, but given that the whole point is to give an idea of scale I wish they'd come up with something else. :)
So wouldn't panning across the sky from whatever vantage point actually produce that movement? Same as when you point a telescope and pan, the stars move against your view...?
e: Ah, but as someone else points out, the trip must actually exceed the speed of light, so the whole thing is nonsense. The author should recast things the way you describe them, and thus solve multiple problems at once.
Now I'm confused. What happens when you pan from the moon to the sun (during a new moon, when they're ostensibly both visible)? If you do it quite quickly you are panning faster than the speed of light? (In the interpretatio: 'if a physical object remained at the center of your scope as you panned, and started at the moon, it would have to move faster than the speed of light, to follow your pan?)
So if you pan from one thing to another and they're 1 light-minute away and you take one minute to pan, does it make sense you are 'panning at the speed of light'? For something that leaves one object and goes toward another?
What do you think of this?
There might be situations where it makes sense to map an angular speed to some sort of absolute speed, but it just doesn't work in this particular example.
in this sense - if there is an intuitive sense of the distance of the camera and the high level of zoom - it makes sense to speak of an object leaving earth at the velocity that lets it stay in the center of the frame as we pan.
doesn't it?
By your interpretation, the camera lens is at a fixed point and then simply "swings" from pointing at Earth to point at Mars. But, from such a supposed point, both the Earth and Mars would be fixed points rather than objects with "multi-pixel" width.
So the fact that both the Earth & Mars are viewable as non-point objects implies translation rather than rotation... and so GP's gripe stands =)
[edit: oh, and what shardling says too]
If the camera lens is at a fixed point and then swings from pointing at Earth to pointing at Mars, and we imagine how fast something would have to travel leaving Earth to remain at the center of the camera sensor as it pans - isn't the obvious question "how far away are we??" So it doesn't really work.
It also doesn't work because at different camera locations the Earth and the Mars would have different relative sizes... I suppose we should state that this will be an equilateral triangle formed between the Earth, Mars, and the Camera, the "height" of the equilateral triangle is x, and that Earth will be so many pixels wide on that camera when zoomed 2000x (or whatever).
This interpretation might be specific enough and also match the experience.
1. Choose a position where the proportional sizes of the Earth, Moon and Mars are what they are on the page. This is likely far away above the ecliptic (the plane the planets are in).
2. Choose a telescope focal length to set the right scale for the planets. Ie magnification.
3. Pan and imagine there is an object in the ecliptic plane at the center of your field of view. Mention the calculated speed of the object.
This all results in a moving star field.
Edited for smiley.
But yes, while the project looks superficially nice, it seems to be riddled with small errors. Hopefully the author incorporates some of the feedback!
Since the starfield was periodic, it looked to me as if it were staying still or moving backwards at times (the wagon-wheel effect[1]) :(
[1] http://en.wikipedia.org/wiki/Wagon-wheel_effect
It takes 13 minutes from light to get to Mars from the sun, and I think that'll also work out to be close to the "average" time from Earth to Mars.
In any case, you're right that apparently the demo exceeds the speed of light at some point, because it doesn't last for 4 minutes. Someone else suggests that the motion be interpreted as a fast pan rather than a physical motion, which is how this should have been implemented to not contradict the laws of physics. :)
Anyway, your idea wouldn't work. If you press on one end of the stick, it would issue a pressure wave along the length of the stick near the speed of light (depending on its material), so you haven't gained anything.
Wifi signals to Mars travel at the speed of light in a vacuum. This is faster than any mechanical wave because the changing forces of compression between the atoms in the medium must still obey the speed of light.
plus Sun, that would be really cool!!
http://www.traipse.com/earth_and_moon/
Example: http://www.astrobio.net/images/galleryimages_images/Gallery_... This is a real image and is not CG.
Another one: http://eol.jsc.nasa.gov/sseop/images/ISD/highres/AS17/AS17-1...
http://www.traipse.com/earth_and_moon/index.html
edit: just large image: http://www.traipse.com/earth_and_moon/earth_and_moon_1280.jp...
I would get that tattooed if I was into that kind of thing.