What If Life On Earth Didn't Start On Earth? [View all]

...Earlier this month, astronomers announced the stunning discovery of Oumuamua, an alien asteroid. Diving in from above the plane of planetary orbits that define our solar system, Oumuamua's trajectory and speed tells us it must be a fragment of another solar system. Ejected from some distant star system, it's been tumbling through space for billions of years. Even its needle-like shape (inferred from reflected sunlight) is unlike anything we've found orbiting the sun. Oumuamua is, without doubt, of elsewhere. Though we've long thought fragments like it must exist, Oumuamua marks the first time we humans have ever seen a visitor pass through our little corner of the universe.

And that's where the other story of life on Earth begins.

Panspermia, is the name for the alternative to abiogenesis. The idea is simple: Life did not begin on Earth but was, instead, transported here from somewhere else in the universe. Like seedpods floating on the wind 'til they fall and take root, life on Earth is the child of a distant parent. In the panspermian view (or at least one version of it), an ancient life-bearing version of Oumuamua fell on Earth some three or four billion years ago. Hardy cells buried deep in the rock matrix of that alien asteroid were freed in the impact, seeding our world with its first microbes.

It is, without doubt, a mind-blowing idea. In fact there's a lot of science-fiction based on panspermia conceits. For example, if you add an intelligent species doing the seeding, you find panspermia as the core idea of Ridley Scott's Prometheus. You can also find echoes of it the popular series The Expanse.

Now, with the visit of Oumuamua, the science behind panspermia's science-fiction-y sounding premise gets a little kick upward on the plausibility scale.

https://www.npr.org/sections/13.7/2017/12/15/571122951/what-if-life-on-earth-didn-t-start-on-earth?utm_source=facebook.com&utm_medium=social&utm_campaign=npr&utm_term=nprnews&utm_content=2044