A planetary odd couple has provided astronomers with a huge enigma to solve from behind their telescopes. Orbiting around a star called Keplar-36 in a solar system 1,200 light years away, the two planets neighbor each other despite wildly different compositions. One consists of rocky terrain like the inner-planets in Earth’s neighborhood. The other is most likely a swirling ball of gas. It’s as if Earth and Neptune decided to become next-door neighbors--without disaster striking. If Neptune were to leap several thousands of million miles towards the sun, the nebulous planet would prove volatile so close to the sun’s heat. Its massive size would alter Earth’s existence, perhaps even destroying the planet. Gravity might not be the most powerful force, but it can do a fair amount of damage.
So scientists are quite surprised that the planets near Keplar-36 have survived as close to each other as they have. The Earth-like planet, which scientists refer to as Keplar-36b, is one and a half times larger than our home and far more massive. The other, with the predictable name Keplar-36c, is nearly four times as large as Earth and stuffed full with eight times the mass. In my mind, I’ve made a fruit model to try to grasp the size differences, but even a grapefruit to watermelon ratio cannot fully convey the hugeness of the new planets.
These ginormous bodies, for reasons unknown to astronomers, have elected to co-exist closer to each other than any two planets in our system--closer than Mercury and Venus, which have the smallest orbits. A year on Keplar-36b is two weeks on Earth, while a year on the outer planet takes a whole 16 Earth days. Almost four times a year, the planets align, becoming closer to each other than the moon is to the Earth. That’s a mind-blowing proximity!
As you can imagine it’s not easy for these giants to exist in the same solar system. Earthquakes shake the smaller planet frequently as the gravitational fields clash with each other. But what’s uncomfortable for the planets is exciting for the international team of researchers who unraveled their masses, sizes and characteristics based on calculations from knowledge of their host star. The Keplar-36 solar system complicates the notions of planet formation. Scientists will continue to analyze the tantalizing trove of data in their quest to understand how planets form, migrate and interact with other bodies.
In the meantime, the Keplar-36 giants will continue to amaze scientists at their ability to survive in such close quarters.