[HN Gopher] 2I/Borisov, the First Interstellar Comet to Have Vis... ___________________________________________________________________ 2I/Borisov, the First Interstellar Comet to Have Visited Our Solar System Author : wglb Score : 74 points Date : 2021-04-04 14:02 UTC (8 hours ago) (HTM) web link (www.newsclick.in) (TXT) w3m dump (www.newsclick.in) | e40 wrote: | Anton Petrov has a few videos on this | https://www.youtube.com/channel/UCciQ8wFcVoIIMi-lfu8-cjQ/sea... | He is one of my favorite youtubers. | sam-2727 wrote: | I think the article title is not representing the actual finding | well. Stated better in this article: | https://earthsky.org/space/2i-borisov-pristine-comet-interst..., | "2I/Borisov could represent the first truly pristine comet ever | observed," meaning it hasn't interacted with a star before. | dongobongo wrote: | A company I work with recently started design and development for | space craft to catch Borisov or Omouamoua, the other extra solar | object that recently passed by, using a nuclear decay heat source | and Hall effect thrusters. It's pretty realistic and doable - no | bleeding edge technologies. Very high power density, very high | isp, very fast space craft. Apparently, they can achieve 100km/s | + velocity delta for a very small payload: | https://www.nasa.gov/directorates/spacetech/niac/2021_Phase_... | | The same system could do a Mars visit and return to Earth for | small payloads in 50 days. | | This stuff needs to get funded! They are funded for initial | studies and design with NASA, but I know they are looking for | extra funding to pull off the mission faster without being tied | to NASA's timelines and mercurial objectives. | lrem wrote: | Why? | | I appreciate the coolness factor. But, unless the payload can | be enough to pull off a 1998 Bruce Willis, what's the | _immediate_ benefit? Or, would this be fundamental to some | research? | dongobongo wrote: | Regarding Omouamoua, we just observed for the first time in | human history, a cylinder or plate shaped object from another | star flying through our solar system with questionable | orbital velocities (we are not quite sure how to explain a | small acceleration it had). A cylinder/plate is not a low | energy geometry (things like to turn into spherical type | objects over time), it's from another solar system, we don't | know very much about it. How could you not want to visit it? | | It's an opportunity to pull off a speed and distance record, | visit something from another solar system, resolve big | research questions about its shape, composition, origin and | rule out any theories of its possible intelligent origin. | They are also pursuing it to showcase the benefits of nuclear | heat for space. | sneak wrote: | Sol is the name of our star, so there is only one Solar | system. | vmception wrote: | This is a more of an etymology issue than what you think, | if you need to look up the word etymology, I'm referring | to the the history of the words and not suggesting any | changing meaning | codeulike wrote: | solar system (noun) | | earth science - the sun and the group of planets that | move around it, _or a similar system somewhere else in | the universe_ | | (Definition of the solar system from the Cambridge | Academic Content Dictionary (c) Cambridge University | Press) | | https://dictionary.cambridge.org/dictionary/english/solar | -sy... | dvh wrote: | Because oumuamua had aspect ratio 10:1 | dboreham wrote: | Like the bounty hunter's ship. | cambalache wrote: | It didnt. It had a perceived dimming factor of 10:1 which | suggests (but does not prove) a "weird" shape | Fordec wrote: | Let's see.. | | Search for evidence of life outside the solar system. Unless | you're planning a trip to another star system this is all | we've got in our lifetimes. | | Hitching a fast ride to the outer edges of the solar system | since it's on a hyperbolic trajectory. | | What is the asteroid made of? That shape of asteroid is not | normal. Usually they're rubble piles, these were different. | Is there formation methods we don't yet know? Were they | fragments of a planet's destruction? | | On an engineering level, we've never had to rendezvous with | something on this trajectory before. Can we? | pyuser583 wrote: | Dont underplay the "coolness factor." The moon landing was | pretty cool. Not practical, but freaking cool. | | We need more coolness in public policy. | azernik wrote: | It would be absolutely helpful to astronomy and planetary | science research. We have never in history looked at | extrasolar material up close. | | And if it is indeed relatively cheap, it doesn't need to be | "fundamental". | mynegation wrote: | That is how progress works. Lots of things were researched or | invented before progress in other areas (materials, | economics, society, other scientific finds...) made these | findings useful or even feasible. You never know when and why | you will need this, the only thing you know - it will be used | eventually. Maybe this will give some important clues into | the future interstellar travel, maybe the tricks and | technologies invented for this mission will be used | elsewhere, maybe sample will give important clues into the | origins and probability of life. | TheBlight wrote: | How would you locate their precise position? | _Microft wrote: | Do you know how these chargeable atomic batteries (,,CAB") | which are mentioned on the NASA webpage work? A web search does | not return anything useful. | marshmallow_12 wrote: | if it's what i think they are, they are essentially batteries | with a radioactive source. It relies on the gradual decay of | the source to create energy which is somehow harnessed and | used as a power source. I have learnt here on HN that they | last many years, are used on space projects such as the | voyager probes, and more recently, the mars rover. They are | impractical for other uses, such as powering your fridge and | home. And their price is.... astronomical. | _Microft wrote: | Atomic batteries are a thing; I was wondering how they | could be made chargeable. | dongobongo wrote: | The typical radioisotope generator is a Plutonium-238 source | like the MMRTG on the Mars rovers. The Plutonium decays by | alpha emission with a half life of 80+ years. The problem is | there is a very limited supply of Plutonium-238 - we use the | entire supply for Mars Rover - and it's very controlled | material. | | The CAB starts with a non-radioactive material like Cobalt-59 | spheres placed in a ceramic matrix. It is then put into a | nuclear reactor where it turns into Cobalt-60, which releases | energy by beta and gamma emission with a half life of 5 | years. This charging can be done every couple years to | generate more Cobalt-60 inside the device. Such a power | source is something like 40x as power dense as the Pu-238 | source and since it's made of high temperature ceramics, it | can go to very high temperatures which is very useful for | space generators where you have to reject heat using | blackbody radiators. | hsnewman wrote: | The title is incorrect (most likely). It is the "First Known | Intersteller Commet to have visited our solar system"! | URfejk wrote: | Indeed. | [deleted] | Klwohu wrote: | It irritates me to read claims like this. Our solar system is | billions of years old. How could we possibly know if 2I/Borisov | is the very, very absolute first interstellar comet to have | visited our solar system? | | Lazy stupid science press. | macintux wrote: | A title missing one word, "known"; the body of the news item | doesn't seem controversial. | | Doesn't seem worthy of such contempt. | lippel82 wrote: | The headline seems to be plainly wrong. It's an interstellar | comet that supposedly has not had a close encounter with another | star. But it certainly is not the "first interstellar comet to | have visited our solar system", or did I miss something? | UnlockedSecrets wrote: | It is the first confirmed interstellar comet and so is the | first under the interstellar comet classification, Unfortunate | that the headline does not contain that detail however. | davidcuddeback wrote: | It's somewhat debatable. 1I/Omuamua was reclassified as an | asteroid because it didn't exhibit a coma. But it's possible | that it's a remnant of a comet. | firebaze wrote: | Despite reading quite a lot about astronomy, comets and | asteroids and the history of all of the three, I didn't get | the distinction between asteroids and comets yet. I | understand the composition makes the difference, but I didn't | get why we expect exactly two (!) distinct categories of | intersolar/interstellar objects, and giving them exactly two | distinct names. Why not more, or less (i.e. no distinction at | all, just a summary of the probable composition)? | | Why is this so? Is there a fundamental reason to make this | special distinction, or is it just "tradition"? | garmaine wrote: | Mostly tradition. Asteroids have had their volatiles baked | off their surface, or never had them due to forming inside | the frost line. But it's not a very intrinsically | meaningful distinction--it's more about what they look like | from the vantage point of Earth as they come by on close | approach. | AnimalMuppet wrote: | Asteroids mostly have circular orbits. Comets (at least the | ones we see) tend to have very highly eliptical orbits. | That I think is the origin of the distinction. | | But asteroids also tend to be at lower distances from the | sun than comets. That in turn leads to them tending to be | composed more of rocky material, whereas comets have more | ice. | | I am not an astronomer, so any and all details may be in | error. Corrections are welcome. ___________________________________________________________________ (page generated 2021-04-04 23:00 UTC)