[HN Gopher] 2I/Borisov, the First Interstellar Comet to Have Vis...
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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.
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