I spent quite a lot of time many years ago doing my own independent checks on astronomy.
I started down this line after an argument with a friend who believed in astrology. It became apparent that they were talking about planets being in different constellations to the ones I’d seen them in. I forget the details of their particular brand of astrology, but they had an algorithm for calculating a sort-of ‘logical’ position of the planets in the 12 zodiacal signs, and this algorithm did not match observation, even given that the zodiacal signs do not line up neatly with modern constellations. They were scornful that I was unable to tell them where, say, Venus would be in 12 years time, or where it was when I was born.
So challenged, I set to.
The scientific algorithms for doing this are not entirely trivial. I got hold of a copy of Jean Meeus’ Astronomical Algorithms, and it took me quite a lot of work to understand them, and then even longer to implement them so I could answer that sort of question. They are hopelessly and messily empirical (which I take as a good sign) - there is a daunting number of coefficients. Eventually I got it working, and could match observation to prediction of planetary positions to my satisfaction—when I looked at them, the planets were where my calculations said they should be, more or less.
It’s hard with amateur equipment to measure accurate locations in the sky (e.g. how high and in which direction is a particular star at a particular time), but relative ones are much easier (e.g. how close is Venus to a particular star at a particular time). The gold standard for this sort of stuff is occultations—where you predict that a planet will occult (pass in front of) a star. There weren’t any of those happening around the time I was doing it, but I was able to verify the calculations for other occultations that people had observed (and photographed) at the date and times I had calculated.
These days, software to calculate this stuff—and to visualise it, which I never managed—is widely available. There are many smartphone apps that will show you these calculations overlaid on to the sky when you hold your phone up to it. (Although IME their absolute accuracy isn’t brilliant, which I think is due to the orientation sensors being not that good.) This makes checking these sorts of predictions very, very easy. Although of course you can’t check that there isn’t, say, a team of astronomers making observations and regularly adjusting the data that gets to your phone.
I was also able to independently replicate enough of Fred Espenak’s NASA eclipse calculations to completely convince me he was right. (After I found several bugs in my own code.) Perhaps the most spectacular verification was replicating the calculations for the solar eclipse of 11 August 1999. I was also able to travel to the path of totality in France, and it turned up slap on time and in place. This was amazing, and I strongly urge anyone reading this to make the effort to travel to the path of totality of any eclipse they can.
Until I’d played around with these calculations, I hadn’t appreciated just how spectacularly accurate they have to be. You only need a teeny-tiny error in the locations of the Sun/Moon/Earth system for the shadow cast by the moon on the Earth to be in a very different place.
I also replicated the calculations for the transit of Venus in 2004. I was able to observe it, and it took place exactly as predicted so far as I was able to measure—to within, say, 10 seconds or so. (I didn’t replicate the calculations for the transit in 2012 - no time and I’d forgotten about how my ghastly mess of code worked—and I wasn’t able to observe it either, since it was cloudy where I was at the time.)
More recently, you can calculate Iridium flares and ISS transits. Again, you have to be extremely accurate in calculations to be able to predict where they will occur, and they turn up as promised (except when it’s cloudy). And again, there are plenty of websites and apps that will do the calculations for you. With a pair of high-magnification binoculars you can even see that the ISS isn’t round.
All this isn’t complete and perfect verification. But it’s pretty good Bayesian evidence in the direction that all that stuff about orbits and satellites is true.
One thing I should mention where I wasn’t able to get a very good match between my own observations and mainstream science.
The Sun and the Moon are very, very close in their apparent diameter in the sky. They are almost exactly the same size. You can measure them yourself and compare, although this is a bit fiddly; I certainly got well within my own measurement errors, although those errors were large. However, you can verify it very easily and directly at the time of solar eclipses. They are so near in size that the wobbliness of the Moon’s orbit means that sometimes the Sun is just-smaller than the Moon (when you get a total eclipse) and sometimes it is just-bigger (when you get an annular eclipse).
But they are very, very different in their actual size, and in their distance from the Earth. In Father Ted terms, the Moon is small and close; the Sun is large and far away. In rough terms, the Moon is 400,000 km away and 3,400 km across, and the Sun is 150m km away and 1.4m km across. You don’t have to change any one of those four measurements much for them to be quite different apparent sizes from the Earth. Indeed, if you do the calculations (which I can personally attest to), if you go back far enough in time they weren’t the same apparent size, and nor are they if you go forward a long way in to the future.
Why? Why this coincidence? And why is it only happening at just the times when humans are around to observe it?
So far as I know, we have no good theories apart from “it just happened to work out that way”. This is pretty unsatisfying.
There are so many possible coincidences, it would be surprising if none of them happened.
I observed 2012 transit of Venus, right on schedule.
Don’t know an easy way to prove changing earth-moon distance, but changes in speed of earth’s rotation can be seen as changes in number of days per year, visible in growth layers in fossil coral. Taking a magnifying glass to the right museum might allow individual verification. http://www.nature.com/nature/journal/v197/n4871/abs/197948a0.html
The closest analogue I have to that is grabbing planet positions and velocities from JPL’s HORIZONS system, then doing small time steps holding accelerations constant.
That’s how I know the (mathematical) solar system behaves as claimed. Except that Mercury’s orbit will eventually become so elliptical and gain so much energy that it careens in and out of the solar system until it flies off to infinity (or people are also right about the limitations of the approximation technique I was using).
I spent quite a lot of time many years ago doing my own independent checks on astronomy.
I started down this line after an argument with a friend who believed in astrology. It became apparent that they were talking about planets being in different constellations to the ones I’d seen them in. I forget the details of their particular brand of astrology, but they had an algorithm for calculating a sort-of ‘logical’ position of the planets in the 12 zodiacal signs, and this algorithm did not match observation, even given that the zodiacal signs do not line up neatly with modern constellations. They were scornful that I was unable to tell them where, say, Venus would be in 12 years time, or where it was when I was born.
So challenged, I set to.
The scientific algorithms for doing this are not entirely trivial. I got hold of a copy of Jean Meeus’ Astronomical Algorithms, and it took me quite a lot of work to understand them, and then even longer to implement them so I could answer that sort of question. They are hopelessly and messily empirical (which I take as a good sign) - there is a daunting number of coefficients. Eventually I got it working, and could match observation to prediction of planetary positions to my satisfaction—when I looked at them, the planets were where my calculations said they should be, more or less.
It’s hard with amateur equipment to measure accurate locations in the sky (e.g. how high and in which direction is a particular star at a particular time), but relative ones are much easier (e.g. how close is Venus to a particular star at a particular time). The gold standard for this sort of stuff is occultations—where you predict that a planet will occult (pass in front of) a star. There weren’t any of those happening around the time I was doing it, but I was able to verify the calculations for other occultations that people had observed (and photographed) at the date and times I had calculated.
These days, software to calculate this stuff—and to visualise it, which I never managed—is widely available. There are many smartphone apps that will show you these calculations overlaid on to the sky when you hold your phone up to it. (Although IME their absolute accuracy isn’t brilliant, which I think is due to the orientation sensors being not that good.) This makes checking these sorts of predictions very, very easy. Although of course you can’t check that there isn’t, say, a team of astronomers making observations and regularly adjusting the data that gets to your phone.
I was also able to independently replicate enough of Fred Espenak’s NASA eclipse calculations to completely convince me he was right. (After I found several bugs in my own code.) Perhaps the most spectacular verification was replicating the calculations for the solar eclipse of 11 August 1999. I was also able to travel to the path of totality in France, and it turned up slap on time and in place. This was amazing, and I strongly urge anyone reading this to make the effort to travel to the path of totality of any eclipse they can.
Until I’d played around with these calculations, I hadn’t appreciated just how spectacularly accurate they have to be. You only need a teeny-tiny error in the locations of the Sun/Moon/Earth system for the shadow cast by the moon on the Earth to be in a very different place.
I also replicated the calculations for the transit of Venus in 2004. I was able to observe it, and it took place exactly as predicted so far as I was able to measure—to within, say, 10 seconds or so. (I didn’t replicate the calculations for the transit in 2012 - no time and I’d forgotten about how my ghastly mess of code worked—and I wasn’t able to observe it either, since it was cloudy where I was at the time.)
More recently, you can calculate Iridium flares and ISS transits. Again, you have to be extremely accurate in calculations to be able to predict where they will occur, and they turn up as promised (except when it’s cloudy). And again, there are plenty of websites and apps that will do the calculations for you. With a pair of high-magnification binoculars you can even see that the ISS isn’t round.
All this isn’t complete and perfect verification. But it’s pretty good Bayesian evidence in the direction that all that stuff about orbits and satellites is true.
One thing I should mention where I wasn’t able to get a very good match between my own observations and mainstream science.
The Sun and the Moon are very, very close in their apparent diameter in the sky. They are almost exactly the same size. You can measure them yourself and compare, although this is a bit fiddly; I certainly got well within my own measurement errors, although those errors were large. However, you can verify it very easily and directly at the time of solar eclipses. They are so near in size that the wobbliness of the Moon’s orbit means that sometimes the Sun is just-smaller than the Moon (when you get a total eclipse) and sometimes it is just-bigger (when you get an annular eclipse).
But they are very, very different in their actual size, and in their distance from the Earth. In Father Ted terms, the Moon is small and close; the Sun is large and far away. In rough terms, the Moon is 400,000 km away and 3,400 km across, and the Sun is 150m km away and 1.4m km across. You don’t have to change any one of those four measurements much for them to be quite different apparent sizes from the Earth. Indeed, if you do the calculations (which I can personally attest to), if you go back far enough in time they weren’t the same apparent size, and nor are they if you go forward a long way in to the future.
Why? Why this coincidence? And why is it only happening at just the times when humans are around to observe it?
So far as I know, we have no good theories apart from “it just happened to work out that way”. This is pretty unsatisfying.
There are so many possible coincidences, it would be surprising if none of them happened.
I observed 2012 transit of Venus, right on schedule.
Don’t know an easy way to prove changing earth-moon distance, but changes in speed of earth’s rotation can be seen as changes in number of days per year, visible in growth layers in fossil coral. Taking a magnifying glass to the right museum might allow individual verification.
http://www.nature.com/nature/journal/v197/n4871/abs/197948a0.html
Keep in mind that the earth-moon distance is not constant. The moon appeared larger in the past and will appear smaller in the future.
Wow.
The closest analogue I have to that is grabbing planet positions and velocities from JPL’s HORIZONS system, then doing small time steps holding accelerations constant.
That’s how I know the (mathematical) solar system behaves as claimed. Except that Mercury’s orbit will eventually become so elliptical and gain so much energy that it careens in and out of the solar system until it flies off to infinity (or people are also right about the limitations of the approximation technique I was using).