https://en.wikipedia.org/wiki/%CA%BBOumuamua

"ʻOumuamua (/oʊˈmuːəˈmuːə/ (About this sound listen)) is the first known interstellar object to pass through the Solar System. Formally designated 1I/2017 U1, it was discovered by Robert Weryk using the Pan-STARRS telescope on 19 October 2017, 40 days after it passed its closest point to the Sun. When first seen, it was about 33,000,000 km (21,000,000 mi; 0.22 AU) from Earth (about 85 times as far away as the Moon), and already heading away from the Sun. Initially assumed to be a comet, it was reclassified as an asteroid a week later, then the first of a new class of interstellar objects.

ʻOumuamua is a relatively small object, estimated to be 180 by 30 meters (600 ft × 100 ft) in size. It is dark and very red, similar to objects in the outer Solar System. It is moving so fast relative to the Sun that there is no chance it originated in the Solar System, nor can it be captured into orbit, so it will eventually leave the Solar System and resume traveling in interstellar space. ʻOumuamua's system of origin and the amount of time it has been traveling among the stars are unknown."

What can we learn from this encounter?

What is the chance an ejected asteroid passes so close to a star? (typical distance between stars is 1 mil times bigger)

0.25 au perihelion.

How many before we saw this the last 100 years?

https://www.nasa.gov/planetarydefense/faq/interstellar

The reason this came from outside is because of the unrelated to solar system plane of rotation trajectory and the fact its speed at "infinity" is over 25 km/sec implying a positive net energy and not a bound object. An object that has net positive energy can escape to infinity with nonzero speed there so its not bound to the system like planets and asteroid etc. These can also eventually in many body interactions acquire positive energy and be ejected from the system and this is how this likely also was ejected from another system and came to our own after possibly millions of years of travel.

At its infinity-speed (speed at very large distances to ignore sun) it takes about 50000 years to travel from one system to the vicinity of another but given how small the actual inner solar system is compared to that interstellar distance you can imagine how lucky this encounter was for that object.

This is by the way the only realistic way earth can be wiped out with a collision that there would be very little we could do about or anticipate for a long time. It came with high speed from far away meaning if such other object were to have 100-500km size and was traveling at 25 km/h we would have only (say first spotted from triple the orbit of Pluto distance which is from what we can detect such objects now given the other dwarf planets we are only recently finding there) 20 years to protect from it if it was recognized it was on a collision trajectory. At triple the relative to this system speed, as its still possible, it could take less than 7 years. There is close to nothing right now that can be done about some 100-500k object moving so fast in that time frame. It is of course a super tiny probability probably order 10^-23 or less per few billion years (similar to the chance for technologically advanced life to emerge in a system in my past calculations) but the only one i can see right away as a life ending event developing so quickly. How fitting that the risk is similar order magnitude as the probability to emerge.

Close encounters of the turd kind.

Shhiittt happens.

I can go all day.

P.s. I am available for children's parties.

And yet, civilization sees fit to spend millions to monitor it for radio transmissions. This must also be related to the chance to emerge in some philosophical way.

Thanks Masque! I've always had a hankering for random space debris. It adds zest to life.

wow, this is pretty ****ing cool to me

I don't have the time unfortunately to think or calculate how an object traveling that fast decided to bust such a sharp U-IE after it entered that solar system, It's pathway is unintuitive. I did take the time out to look up when this first ****er was detected. Not soon enough.

https://youtu.be/tbdpv7G_PPg

Just basic 2 body kepler problem with positive energy resulting in hyperbolic trajectory that is coming from a direction that is not parallel to the plane of rotation of our solar system. It is that curved because it was a very close encounter with the sun. All the activity in our solar system (ie almost all planets , comets etc) is taking place basically in a very narrow range, the plane vertical to the total angular momentum of the solar system. Same is true for galaxies. If the interactions are very frequent you get a sphere like the planets or sun (high density of matter) otherwise you get a disk.

https://en.wikipedia.org/wiki/Kepler_problem

https://en.wikipedia.org/wiki/Format...e_Solar_System

Because of the conservation of angular momentum, the nebula spun faster as it collapsed. As the material within the nebula condensed, the atoms within it began to collide with increasing frequency, converting their kinetic energy into heat. The centre, where most of the mass collected, became increasingly hotter than the surrounding disc.[10] Over about 100,000 years,[9] the competing forces of gravity, gas pressure, magnetic fields, and rotation caused the contracting nebula to flatten into a spinning protoplanetary disc with a diameter of about 200 AU[10] and form a hot, dense protostar (a star in which hydrogen fusion has not yet begun) at the centre.[21]