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Hubble Observes First Confirmed Interstellar Comet
- dmix 7y agoThis might be a dumb question but how does a comet reach 110,000mph? From an explosion + slingshotting off gravity?
- saagarjha 7y agoProbably just gravity+the relative velocities of it and the sun. That’s about the orbital speed of Mercury, so it’s not an insane speed.
- Svoka 7y agoactually it's almost exactly Venus' orbital speed.
- saagarjha 7y agoYou sure you're using the right units?
- digitalsushi 7y agoit's like 70%, more than certainly the same order of magnitude. each planet closer to the sun has to zoom faster than the one before it, to not fall in
- saagarjha 7y agoI'm aware of how orbital mechanics works, but I brought up units specifically since 70% is close to the ratio between kilometers and miles. The orbital speed of Mercury, for reference, is much closer: https://www.wolframalpha.com/input/?i=orbital+speed+of+mercury https://www.wolframalpha.com/input/?i=orbital+speed+of+mercu...
- windsurfer 7y agoIt's relative to the solar system. The solar system itself is traveling at 514,000 mph relative to the center of the galaxy.
- perl4ever 7y agoI find it weird when people quote large velocities in mph. Sure, we measure normal things in mph, but who has a reference point for 500 thousand mph? Whereas, I, and I would have though other people, have a general idea that rockets and such travel at a single or low double digit mi/s, and (maybe it's just me) I would think the speed of light at about 186 thousand miles per second is well known.
- stouset 7y agoIt’s from interstellar space, and not from our solar system. Virtually all of this speed is simply from it being in a different relative reference frame to ours.
- wil421 7y agoGreat but old video about frame of reference.[1] Is the comet coming towards us or are we going towards it? Does a dropped ball fall to the earth or are we going upwards to meet it? [1] https://youtu.be/lbnDSdrriGI https://youtu.be/lbnDSdrriGI
- breck 7y agoif I understand correctly that’s not extraordinary fast. NASA has sent things over 150k mph.
- dmix 7y agoOh interesting, you're right the Juno spacecraft went 130,000mph. Fascinating. https://en.wikipedia.org/wiki/List_of_vehicle_speed_records#Spacecraft https://en.wikipedia.org/wiki/List_of_vehicle_speed_records#...
- walrus01 7y agoI'm honestly kind of surprised to see people using miles per hour for measurement of speeds in space. I guess I should specify how many leagues my car can travel per hogshead, as well.
- dmix 7y agoI'm from Canada but the article used MPH so I kept it. I'd rather not convert every number I copy/paste. Plus everyone gets the gist of what mph means. It's common sense.
- perl4ever 7y agoOrbital velocities are generally quoted in miles per second or km/s, and so is the speed of light. So mph tends to lack context.
- ceejayoz 7y agoInitial velocity as it entered the sun's influence, plus acceleration from the sun while under that influence. The Parker Solar Probe will hit 430,000 mph as it falls towards the sun, for example. https://en.wikipedia.org/wiki/Parker_Solar_Probe https://en.wikipedia.org/wiki/Parker_Solar_Probe
- caleb-allen 7y agoThis is so cool! I love seeing the influence of amateur astronomers, like in this case.
- windsurfer 7y agoI hope we can get spectroscopy done on the tail! It would give us a really unprecedented look into the material composition of other solar systems.
- digitalsushi 7y agoWouldn't we get the same composition from the spectral analysis of the suns they orbit? Serious question, not a poke. I'm not an astronomy nerd and would love some education from a hn friend.
- gbear605 7y agoI’m not an astronomer, but I’d hypothesize that the composition of the non-solar objects in a solar system (eg. a comet) is different from the composition of the sun in that solar system.
- pmalynin 7y agoThe spectra we receive will include the absorption lines from passing through the stuff around the other sun and surrounding matter. I don't know how strong the effect will be, but it should be observable.
- doctoboggan 7y agoThe included video stated that the comet is composed of similar materials to those that make up our solar system. I am assuming they discovered that using Hubble's spectroscopy capabilities (STIS).
- downrightmike 7y agoAll of the materials would come from early nova/super nova. I'd wager we'd see a similar composition across at least the milky way.
- crispyambulance 7y agoI wonder if it wouldn't be possible to launch a multitude of craft orbiting in various places around the solar system and just stay primed and ready to intercept and explore these surprise interstellar visitor objects? Is it impractical to achieve this with something like a long-burning ion propulsion system? These things are really unique and it's not like we'll have any other way to explore something up close from outside the solar system
- wpasc 7y agoIs this one less weird (interesting, unique, etc.) than Oumuamua?
- rshnotsecure 7y agoThis is quite serious. Interstellar objects travel at very fast speed. Comets, because of their highly elliptical orbit, already impact earth at much higher speeds than asteroids. Can only imagine what a hit from something further than the Oort Cloud is. It is very likely that the global flood monomyth is based on the impact of a comet around 13,000 years ago. This was somewhat discounted only 10 years ago, but now is more than the majority consensus in the field (“Younger Dryas Impact Hypothesis”). Comet would have hit Greenland by the way, with many pieces falling apart and hitting North America. This would have destabilized the entire ice shield across that area.
- not2b 7y agoThe Wikipedia article doesn't agree with your assertion that this is "more than the majority consensus in the field", and presents lots of evidence against the hypothesis.
- tonmoy 7y agoHow does a comet cause a global flood? I couldn’t find any hypothesis regarding the link between comet impact and a global flood
- z3t4 7y agoFind some tsunami videos, the water just keep coming. A comet would produce a big wave.
- api 7y agoIt would not create a true global flood but it would create tsunamis and weather disruptions that could certainly by mythologized as such. Since humans are egocentric we would naturally assume it was our fault and that we offended the god(s).
- saberdancer 7y agoThere is no difference between a comet and a asteroid in this kind of situation, both would cause tsunamis. On the other hand, having a huge fireball in the sky, earthquakes, ash falling from the sky, would probably leave an impression along with the tsunami (flood) that would be in the flood story. I seriously doubt the flood stories came from an asteroid or comet impact. Much simpler explanation is that it is a memory of either Black Sea forming or memory of the sea level rising at the end of the ice age.
- Santosh83 7y agoSince the observed composition of the comet is mentioned as being "remarkably" similar to solar system comets isn't there any possibility at all that it could indeed be from within our system? Can no combination of freak gravitational nudges/slingshots, however unlikely, result in the observed orbit?
- Analemma_ 7y agoFrom Wikipedia: "2I/Borisov also has a hyperbolic excess velocity of 32 km/s, much higher than what could be explained by perturbations, which could produce velocities when approaching an infinite distance from the Sun of less than a few km/s"
- stouset 7y agoIf the aphelion (furthest point of its orbit) is significantly farther out than the Oort Cloud, then it fundamentally can’t be from anywhere inside our solar system per orbital mechanics. And in this case, its “orbit” is hyperbolic. Meaning it’s going faster than the escape velocity, so will never return. It’s also a dead giveaway if the eccentricity or direction of its orbit are significantly different than those of the rest of the solar system Edit: For objects as far out as the Oort Cloud, a few relatively small changes in velocity can actually result in hyperbolic orbits. The real distinction is a big difference in velocity.
- sandworm101 7y agoUnless it interacted with other bodies in the ort cloud. If we consider three-body interactions, slingshots, most any trajectory/orbit might be possible.
- trentlott 7y agoIt depends on interobject density and single object mass, I'd reckon. Having it redirect the orbit at velocity might be astronomically (!) low Also, I don't know it's trajectory relative to the solar plane; it might be ruled out by that alone
- 7y ago
- sixothree 7y agoDoes this mean we will only see one pass of this comet? Or did/will it get captured?
- dreamcompiler 7y agoYes. One pass only.
- zentiggr 7y agoIn this case, a hyperbolic trajectory means the orbit isn't closed, which also means the the object's velocity is above escape velocity. The only thing that would possibly change it to a capture scenario would be an extremely close pass to a planet, which theoretically could drain off its excess velocity and would then wind up in some sort of elliptical closed orbit. Since an encounter like that is easy to predict once a trajectory has been calculated, and there's no mention of it doing so, I have to assume it's going to cruise in, pass its closest point to the Sun, and zoom right back out.
- sixothree 7y agoSo that means this is incredibly historic, yes? We have only witnessed one other interstellar object and we did not learn about it in time to make meaningful observations?
- dreamcompiler 7y agoIt's historic in the sense that it's one of the first interstellar objects we've seen. But these things are almost certainly not rare; they only seem so because we've only recently become able to detect them. In 10 years sightings of interstellar objects won't even make the second-tier news feeds.
- sixothree 7y agoWhen my mother was born plate tectonics was a hypothesis. When I was born proof of extra-solar planets did not exist. I know this these objects have been hurling past us for billions of years, but the fact that we spotted one is exciting for me.
- starborn 7y agoI am interested in the fact that an amateur astronomer discovered this and have some subject matter questions. What type/size of telescope would be required? Is this the result of simply arbitrarily scanning night skies? Do amateurs use software of some sort to aide in locating sky locations where undiscovered objects might be? When you do think you’ve found something how do you report it? Do amateur astronomers gravitate toward any one social site, i.e. is there a vibrant Twitter community or subreddit? Was/would Gennedy (and amateurs like her) working in coordination with a group of others (local or distributed). TLDR I want to discover a space object. How do I do this?
- pks016 7y agoYeah. I would like to know this too. The process of this, how to start this kind of things as a beginner.
- sjackso 7y agoYou may want to check out the forum site Cloudy Nights. Here's a thread in the amateur telescope subforum about the instrument that discovered this comet. There's a photo of the telescope and of Borisov four posts in to the thread. https://www.cloudynights.com/topic/677286-homemade-065m-f-15/ https://www.cloudynights.com/topic/677286-homemade-065m-f-15... That particular subforum is full of people who make their own telescopes in their home shops, and it's a fascinating place to visit. From what I can tell, this particular telescope is an extreme example, an instrument manufactured to professional standards by a well-resourced optics professional working in his spare time.
- muxator 7y ago> An artificial satellite also crosses the field of view Can anyone give some hints on how to spot it? Maye it is really evident, but I was not able to identify it.
- novalis78 7y agoWhile Oumuamua was a sentry buoy this ‘comet’ is a confirmation device shielded as ‘interstellar comet’. I wonder who shows up next? This sectors silicon based AI wiping out carbon life forms? Just kidding... hopefully we get to see more of these interstellar objects in the next few years. Exciting!