Exact interstellar measurements might now be possible, thanks to the work of an MU researcher.
Sergei Kopeikin, a professor of physics and astronomy in the College of Arts and Science, solved an anomaly that could allow future scientists to accurately measure cosmological values including the age of the universe itself, according to an MU [news release](http://munews.missouri.edu/news-releases/2012/1009-interstellar-travelers-of-the-future-may-be-helped-by-mu-physicist%E2%80%99s-calculations/).
“(Physicists) measure the expansion of space with cosmological observations,” Kopeikin said. “The observations show that the expansion rate is not constant but changes with acceleration.”
Kopeikin’s findings would allow the acceleration of expansion to be accurately measured. This discovery came about because of an anomaly once thought to be a mechanical error, Kopeikin said.
The Pioneer 10 spacecraft, launched in the 1970s to explore space beyond our solar system, had been sending readings via radio signals that showed the spacecraft to be decelerating as it traveled, Kopeikin said in the release.
“The most common explanation was that the spacecraft was experiencing heat from the energy source onboard,” Kopeikin said. “We could not use solar panels so we had to put on the spacecraft a small nuclear radioactive battery, so people assumed this was the cause of the anomaly.”
Another idea is that the universe is expanding, and because of that expansion, some acceleration in the motion of the spacecraft should be expected, Kopeikin said. This second idea was not immediately evident to those analyzing the anomaly.
“It is not very simple to incorporate the expansion of space to the mathematical equations describing the local dynamics,” Kopeikin said. “I started to think on this problem about a decade ago and started to develop my own mathematical approach. It took quite a long time to put all the details and mathematical equations together in order to start understanding what is going on.”
Cosmologist and assistant professor Haojing Yan works with a team to find the oldest galaxies in the universe. Kopeikin’s discovery will not only aid in measuring travel distances, but will also aid in all areas of cosmology, Yan said.
“If Sergei’s discovery can be proved in the future and further verified by experiments, then this indeed will have a long term impact,” Yan said. “What Sergei has found can be related to any branch cosmology, if this is real. We know our universe is expanding — this is a commonly accepted fact nowadays.”
One very important parameter in measuring the rate of expansion is called the Hubble Constant, Yan said. This constant will have a tremendous amount of impact to every field of cosmology. With Kopeikin’s findings, one can derive the Hubble Constant, which is proportional to the expansion of the universe, he said.
Yan said the Hubble Constant was one of the parameters his team used to determine the age of faraway galaxies.
Though the possibility of far-reaching impact is cause for excitement, Kopeikin said the main goal of his work was to better understand local observations.
“The solar system is a kind of superb laboratory for astronomers because we know precisely the distances between planets and how they move around the sun,” Kopeikin said. “So everything is measurable with much better confidence than the parameters of distant galaxies.”
As far as the possibility of interstellar travel goes, it is within reach but requires better understanding than astronomers have now, Kopeikin said.
“We definitely need a better understanding of how to measure distances and velocities of our space probes going outside of the solar system and how much time exactly it would take to travel to other stars, if we would have any other way around besides conventional chemical rockets,” Kopeikin said.
