MU struggles to repeat 100-year-old eclipse experiment
COLUMBIA - Around one hundred years ago a team of astronomers confirmed Albert Einstein’s theory of general relativity using the solar eclipse.
Now, a group of University of Missouri scientists will use the upcoming eclipse to replicate the same experiment.
Astronomy professor Haojing Yan said the proximity of this eclipse gave him the idea.
“Back then, the people would have to travel long distances, this is what they called an expedition sort of, they needed to bring their instruments and they need to travel far distances to set up things there well in advance. Now we do not need to do that because we have this eclipse that is viewable right at home," he said.
Einstein’s theory says light will bend around a massive object due to gravity. Sir Isaac Newton's theory of gravity already established that light can bend, but Einstein predicted the correct amount of bending. Yan said it happens by a very small amount and only high-mass objects, like the sun, can produce a noticeable effect.
Yan said this is what scientists now call "gravitational lensing," since it is a large object in the foreground that bends the light similar to how a foreground lens focuses light.
To verify this theory, astronomer Sir Arthur Eddington used the 1919 solar eclipse.
Researchers needed to measure the position of the stars with and without the sun in front of them. The problem is stars are not visible when the sun is out, so the eclipse provided a unique opportunity.
“When the eclipse happens, the star’s light is blocked by the shadow, so it won’t be completely dark, but it will be dark enough so you will still be able to see those background stars, so this was exactly what they did,” Yan said.
Eddington’s experiment found the position of the stars altered in the way Einstein predicted, and thus confirmed General Relativity.
Since 1919, Yan said, he thinks two other groups attempted to replicate the experiment, with the latest taking place in 1970.
For Yan, he does not expect his experiment to make any breakthroughs but is doing it for his students and for fun. Although, Yan does hope he and his students may be able to publish a paper out of it if successful.
Even driven by fun and aided with updated technology, the mission is no easy feat. To complete the study, the group needs a telescope with a large field of view to see a good portion of the sky. To accurately measure the positions of the stars, the telescope also needs a high resolution. Unfortunately, high resolution and a large field of view contradict each other.
“In order to do the right thing we have to find a compromise,” Yan explained. “In my case, this kind of comprise is almost impossible.”
Yan and his team spent the last year using the Law Observatory telescope to conduct tests and they discovered it is not functioning well. The telescope is used primarily for education and public use and Yan said it is lacking necessary maintenance.
“This is to my total disappointment and so my only hope now is that we can maybe use a different telescope," Yan said.
MU Physics and Astronomy professor, Linda Godwin is attempting to salvage a 10-inch telescope but the group still has to see if it will fit the requirements of this unique experiment.
“The lesson learned here is you might think after 100 years you might be able to achieve Sir Eddington’s goal much easier, but it still requires a lot of planning, a lot of work,” Yan said.
Despite the setbacks, Yan is not giving up yet and even if the equipment fails to cooperate he says as long as he can still just see the eclipse, it will be a good thing.