One quadrillion celestial bodies behind Neptune
Taiwanese astronomers have discovered that at least one quadrillion celestial bodies with diameters between ten and one hundred meters orbit beyond Neptune. The research team led by astronomer Hsiang-Kuang Chang examined measurement data from NASA's Rossi X-Ray Timing Explorer satellite. In recent years he had observed Scorpius X-1, the brightest X-ray source in the sky.
The scientists looked for brief eclipses from this source. They come about when celestial bodies pass from in front of the source and briefly cover it.
It turns out that numerous small objects have passed Scorpius X-1 in recent years. In all probability they are moving beyond Neptune and thus belong to the Trans-Neptune Objects (TNO), which also includes the planet Pluto. From the frequency of the measured eclipses, the estimated total number of TNOs with diameters between ten and one hundred meters is at least one quadrillion. That's a thousand to a million times what current computer models predict.
This discrepancy may indicate that small TNOs are moving more slowly than previously thought. The researchers are hoping for more clarity from further measurements planned for the future - for example the Herschel and Planck missions of the European Space Agency Esa.