If you Google "SN1987a" you will turn up dozens of hits all explaining
why the first supernova discovered that year proves that the universe is
far older than young-earth creationists ("YECs") want to believe. That
may yet be proved, but the evidence provided by this event does not succeed
at it. It's all about trigonometry, so this is going to get mathematical.
If you want to use mathematics to prove your dogma, then at least get the
math right. The analysis
by Todd Green appears typical, and is both clear and detailed.
A little over seven months after SN1987a first showed up in the sky, a new ring of light appeared around what was left of the star that blew up. Apparently there is a cloud of dust or gasses or something previously ejected from the star long before it went nova, and that cloud was a half-light-year away when it went nova. The brilliant flash of the nova went out in every direction (and was seen on earth in 1987), and it also hit this cloud of dust not quite eight months later, and got reflected from there in every direction. This reflected light reached the earth eight months later than the original flash. What is not clear to me is if this is a flat ring partly viewed on-edge as indicated in the Tufts web page, why do the pictures always show it equally illuminated? Light from the near edge should have gotten here first, then dimmed over the months before light from the far edge started to arrive.
Anyway, the trigonometry works like this. The radius of the ring can be accurately determined by the time it took the light to reach it from the original flash, 0.658 light-years. The angle that forms in our telescopes, 0.808 seconds of arc, provides a multiplier, the ratio between the radius of the ring and the distance between the telescope and the star. The simple calculation is to convert the angle to radians (one radian is the angle formed when one radius is curved around the circle, 360 degrees divided by 2 pi, about 57.3 degrees). There are 60 seconds in a minute, 60 minutes in a degree, and 57.3 degrees in a radian, so we get 3600 times 57.3 divided by 0.808 is our multiplier 255297, multiplied times the known ring radius gives a distance of about 168,000 light-years. The math is good.
What they are not telling you, is that the trigonometry is not known to be valid here. Let me give you an example closer to home, where the same trigonometric calculation fails to get correct answers.
Place an eight-inch (20cm) rod on the floor of your living room or garage near one wall and parallel to it. Draw two straight lines (or stretch threads or tape measures) on the floor six feet (2m) toward a single point on the opposite side. You know it's two meters, but pretend for this experiment that you don't. Measure the angle between those two lines at the point where they meet: if your protractor is good and your eyesight better than mine, you can measure the angle at something like 5.7 degrees. That's one tenth of one radian, so the calculated distance from the rod to your protractor is ten times the length of the rod, or 2 meters. The math works.
Now let's scale up. This is rather harder to actually do, but I'll try to make it easy as a thought experiment. Imagine your rod is much longer, say 1000km, laid along the equator. Draw your two straight lines so they converge at the south pole, and measure the angle between them. The circumference of the earth at the equator is 40,000km (actually 40,075km because the French bungled their measurements when they were defining the meter, but that's less than 0.2% error and can be ignored for our purposes), almost exactly 40 times the length of our new rod. That means 40 of our rods laid end-to-end around the globe exactly fill the 360 degrees, so the angle we measure on our protractor at the south pole should be 360/40 = 9 degrees, which comes out to 9/57.3 or 0.157 radians. Therefore the calculated distance from the pole to the equator will be 1000km/0.157 = 6367km. But wait, the actual known distance is slightly over 10,000km! The calculated distance is wrong by almost 40%.
It gets worse. Go back to our 8-inch rod, and put it on the ice six feet from the north pole ("global warming" is over, so now there's ice there), then draw those straight lines to the south pole and measure the angle: it's now the same 5.7 degrees you measured in your garage. This new calculated distance is wrong by seven orders of magnitude (10,000,000 times). It's the math. If you don't believe me, do the measurements yourself on the surface of a cantaloupe or basketball using an 10mm "rod" placed 10cm from the stem, and a real protractor at the opposite end ("pole"). The error will depend on the relative sizes of the ball and rod and how close to the pole it is, but it will be substantial.
The reason you get wrong answers is that the lines which look straight and flat on your garage floor are actually curved to fit the surface of the earth. For small distances like six feet or a couple miles, the discrepancy is too small to be visible, well below the threshold of measurement error. Add up hundreds or thousands of miles and the errors get quite large. That's why the country roads through the plains of Kansas and Iowa take a jog every few miles: they are correcting for the trigonometric errors.
But wait, light travels in straight lines, right? Wrong again. Look here for a fascinating discussion of the visual effects of light is bending around the earth. Mostly it's atmospheric effects, right? And light travels in straight lines through outer space? Wrong again. Light is also known to bend around heavy gravitational objects like stars and even planets.
These are effects of positive curvature (like a ball), which makes things look larger (and therefore nearer) than they really are. You can also have negative curvature (like a saddle), which makes things look smaller and more distant than actual. You cannot measure the curvature of the earth by testing your garage floor. The actual curvature is smaller than the unavoidable bumps and dust on the concrete. Similarly, the amount of space curvature necessary to render totally useless any distances calculated by triangulation to the Large Magellanic Cloud galaxy (the presumed location of SN1987a), what we can measure of it within reach of our instruments, is much smaller than the amount of the earth's curvature in your garage floor.
With good instruments placed in triangulation, you can measure the curvature of the earth over a distance of a mile or so, but it's so small that the trigonometry basically works. Four orders of magnitude up from there and the trigonometric calculations are completely broken. We have sent space probes out -- not to measure curvature, but they could have -- to distances of a few light-hours (Neptune is 4 light-hours from earth). There are 8760 hours in a year (three orders of magnitude beyond Neptune), and the triangulation tells us SN1987a is 168,000 light-years, another five orders of magnitude beyond that. It doesn't take much curvature to knock a couple orders of magnitude off that, at which point it doesn't prove anything at all about the age of the universe.
The bottom line is that without faster-than-light "warp drive" to put
instruments out there, we do not have the ability to measure anything close
to the accuracy necessary to trust triangulation that far away. The atheists
are not going to tell you that.
500 years ago, nobody could see anything except by the naked eye. I guess magnifying glasses existed, but they enlarge at most two or three times (by holding them just right, short focal-length lenses can enlarge small objects 10x or more, but not well). The human eye is good for about one minute of arc. A point of light smaller than that (like a star) can be seen, but only because it blasts photons all over the retina; there's no resolution. It's what makes stars twinkle: sometimes a photon hits a light receptor on the retina, sometimes it misses.
Anyway, one magnifying lens doesn't do much, but somebody (Galileo? I'm not sure) figured out that two lenses spaced just so produced a huge magnification, way more than the sum of the parts. Two short-focus lenses make a microscope and opened up microbiology. A long and a short make a telescope, and all of a sudden Galileo could see discs for Mars and Jupiter and Saturn, not just points of light, and even rings and moons (points of light going around these discs).
Optical microscopes are good for about four orders of magnitude improvement, then the physics gets in the way. The wavelength of light limits the minimum size you can magnify. So we use X-rays and electrons (shorter wavelength) to get past that limit, but the rules change at four orders of magnitude. Quantum physics kicks in, and the old Newtonian physics simply doesn't work. We can see it happen with our electron microscopes, because we can get behind the rule change. We can manipulate the platform we are trying to measure, so to experiment with how the new rules work. Then there is another rule change some three or four orders of magnitude beyond that, which currently prevents the physicists from building a workable "Grand Unified Theory" (because they don't yet fully understand how the rules work down there). Keep that "four orders of magnitude" (four decimal digits, a factor of about 10,000) in mind.
Now we look at the other end of what two lenses did for us. Optical telescopes also stop working for us somewhere around four orders of magnitude, I think for the same wavelength reason. If you look at the Hubble telescope image of the SN1987a ring(s) and star, you can see that much detail and not more. The image blurs out at a resolution somewhere near 5-10% of the ring diameter, basically around 0.1 second of arc. Guess what? That's only three orders of magnitude past what you can see with a naked eye. Going the other way (smaller, using microscopes) the rules change every four orders of magnitude. Here, we (or rather, the atheists) are assuming that there are no rule changes for eight orders of magnitude. There could be two or more rule changes in that space, and we'd never know it. Unlike microscopy, there's no way to get out there and check our assumptions. Have you heard of "dark matter"? The cosmologists imagine that more than 90% of the mass/energy of the universe cannot be detected by our instruments, because the facts that we can measure don't match their theory. Sounds like a rules change to me.
I'm not saying the atheists are wrong, I'm saying we have no way of knowing, other than sending somebody (or a probe) out there to make the measurements from a different angle. And at 168,000 light-years out, it ain't gonna happen. It can't even happen at 1000 or 100 light-years out. The whole triangulation thing is a fabrication built solidly on guesswork and wishful thinking, with no more validity than the goofy Creationists who postulate changes in the speed of light.
We simply don't know. We cannot know. But it's fun to guess and write fairy tales that pretend to be science.
Tom Pittman
2014 May 7