Hubble telescope finds wandering planets?
The European Space Agency (ESA) announced that the ESA/NASA Hubble Space Telescope has revealed clues to what could be wandering planets, planets which are not orbiting any star. The evidence comes from the observation of six unusually brief microlensing events. Microlensing occurs when a background star brightens temporarily as a foreground object passes between it and the Earth. The drifting objects are far too dim to be seen directly, but instead are detected by the way their gravitational field bends light from a more distant star, making the distant star appear brighter. When microlensing is due to one star passing in front of another, the increase in brightness can last several days, in a typical observation where a dwarf star drifts in front of another star, this could be 18 days. But scientists observing globular cluster M22 have been surprised to observe six unusual microlensing events that lasted less than 20 hours. They are suggesting that this could be due to planet sized objects. What is more, the scale of their observations implies that so called orphan planets may be far more common than was originally thought, making up as much as 10 percent of the mass of this particular cluster. These observations are only possible thanks to the Hubble telescope's high resolution.