Roughly a century ago, Albert Einstein predicted that whenever starlight passes by a closer object, that object's gravity would act as a sort of lens, magnifying and distorting the light.
While Einstein was confident in his math, he had no way to prove his theory since, during his time, there was no way to observe this effect. However, now the Hubble Telescope has validated Einstein's hypothesis and offered new support for the theory of relativity.
Einstien Was Right
Terry Oswalt of Embry-Riddle Aeronautical University said that the research team's discovery provided fresh insight into the origins of stars and galaxies and provided scientists with a way to measure the mass of distant objects.
"The research by Sahu and colleagues provides a new tool for determining the masses of objects we can't easily measure by other means," said Oswalt. "The team determined the mass of a collapsed stellar remnant called a white dwarf star. Such objects have completed their hydrogen-burning life cycle, and thus are the fossils of all prior generations of stars in our Galaxy, the Milky Way."
The Experiment
The experiment in question was carried out by an international team of researchers led by Kailash C. Sahu. The team used the Hubble telescope to study the effect of Stein 2051 B, a white dwarf, on the apparent location of another star. Over the course of eight dates spanning a period of two years, the team observed that more distant star appeared to be moving.
The background star's distance had not actually changed, but the mass of Stein 2051 B had actually warped space around it resulting in an apparent displacement effect on the more distant star. Using this method, Sahu's team was able to calculate that Stein 2051 B is about 2/3 the mass of the sun.
The general idea is that the mass of the white dwarf is proportional to the apparent displacement effect is has on the more distant star. In addition to providing more evidence for the theory of relativity, this allows researchers to calculate the mass of stars and other large objects that they otherwise would not be able to measure.
White Dwarf
Near the end of a star's lifecycle, after it has exhausted its energy, it turns into a densely compact star known as a white dwarf. While roughly the size of the Earth, the densely packed nature of white dwarf stars give them a mass that is roughly comparable to that of the sun which is considered a yellow dwarf.
