Far out cosmology: is our solar system a freak (Introduction)

by David Turell , Wednesday, December 28, 2022, 17:44 (694 days ago) @ David Turell

Thirty years of seeing other planetary models, none are like us:

https://www.sciencealert.com/weve-never-found-anything-like-the-solar-system-is-it-a-fr...

We've learnt many things from this vast catalogue of alien worlds orbiting alien stars. But one small detail stands out like a sore thumb. We've found nothing else out there like our own Solar System.

This has led some to conclude that our home star and its brood could be outliers in some way – perhaps the only planetary system of its kind.

"By extension, this could mean life itself is an outlier; that the conditions that formed Earth and its veneer of self-replicating chemistry are difficult to replicate.

***

"Most exoplanets we've seen so far orbit their stars very closely, practically hugging them; so close that their sizzling temperatures would be much higher than the known habitability range.

***

"Exoplanet science is limited by the capabilities of our technology. More than that, our impression of the true variety of alien worlds risks being limited by our own imagination.

"What's really out there in the Milky Way galaxy, and beyond, may be very different from what we actually see.

***

"By far, the most numerous group of exoplanets is a class that isn't even represented in the Solar System. That's the mini-Neptune – gas-enveloped exoplanets that are smaller than Neptune and larger than Earth in size.

"Most of the confirmed exoplanets are on much shorter orbits than Earth; in fact, more than half have orbits of less than 20 days.

"Most of the exoplanets we've found orbit solitary stars, much like our Sun. Fewer than 10 percent are in multi-star systems. Yet most of the stars in the Milky Way are members of a multi-star systems, with estimates as high as 80 percent seen in a partnership orbiting at least one other star.

"Think about that for a moment, though. Does that mean that exoplanets are more common around single stars – or that exoplanets are harder to detect around multiple stars? The presence of more than one source of light can distort or obscure the very similar (but much smaller) signals we're trying to detect from exoplanets, but it might also be reasoned that multi-star systems complicate planet formation in some way.

"And this brings us back home again, back to our Solar System. As odd as home seems in the context of everything we've found, it might not be uncommon at all."

Comment: it is just too soon to reach any conclusion. The technology needs further development.