What a difference a day makes—or in this case, almost a year. I’m not talking about the romance Dinah Washington sang about 50 years ago, I’m referring to the advances in exoplanet research and how these advances highlight the unique character of Earth to support life.
Most recently, the European HARPS collaboration announced the detection of a star orbited by at least five, maybe seven, planets. The five strongest signals in the data correspond to planets similar to Neptune, each with orbital periods between 6 and 600 days. However, the data indicates that two more planets may orbit this star. One would be a Saturn-sized planet with a six year orbit. The other planet would have a mass 40 percent larger than Earth and orbit the star every 1.2 days. (Past research hints that this small planet is the burned-up cinder of a gas giant.) This discovery shows that astronomers’ tools reach ever closer to achieving the capability to detect a solar system like ours.
The past year also brought the first five planets detected by the Kepler mission—announced in the January meeting of the American Astronomical Society. Earlier this month, Kepler released data on another 300 planets with 400 others awaiting more observations. This research has more than doubled the number of known extrasolar planets. The dramatic increase in known exoplanets enhances the toolbox scientists use to determine the uniqueness of planet Earth.
One finding seems to indicate that solar systems similar to Earth comprise 15 percent of all stars orbited by planets. Yet the one “solar-like” system used to calculate this percentage differs significantly from ours. The star has half the mass of the Sun and emits only a small fraction of the radiation. The masses of the “Jupiter” and “Saturn” in this system also have much smaller masses than their solar-system equivalents. In fact, this extrasolar system appears as a scaled-down version of our own. While some similarities exist, the chances of a system like this supporting a habitable planet are slim.
One final discovery genuinely surprised planet hunters. A significant fraction of the large planets orbiting close to their host star (referred to as “hot Jupiters”) orbit in the wrong direction. Life does not require a particular orbital direction, however, the retrograde orbits of these planets means that the mechanisms that produce these hot-Jupiters also destroy any chance of finding a habitable planet in these systems.
Extraordinary advances occurred in exoplanet research during this past year. As anticipated, the growing number of exoplanets (along with data gathered from our own neighboring planets) continues to support the prediction of RTB’s creation model that Earth’s remarkable capacity to support life arises from divine intervention.