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I'm a little tired of articles mentioning "Harvard Astronomer" to add credibility to this ridiculous theory. Nobody else seriously believes this and we all know

I'm a little tired of articles mentioning "Harvard Astronomer" to add credibility to this ridiculous theory. Nobody else seriously believes this and we all know Avi wants to sell his book. Out of my network of ~200 astronomers/physicists, I haven't heard one person support the idea that this is an alien probe.

cogman10 6y ago
And why would it be? It was HUGE. Why on earth would aliens design a probe so large? It would take a ton of energy to make it to our solar system (like, a star exploding... hmmm..). If aliens have probed us, I DOUBT we would have actually noticed them. Because, likely the probe would be about the size of one of our satellites and maybe even a lot smaller to cut down on the amount of energy needed to get them here.
- hypertele-Xii 6y ago
  Size is so relative. You're thinking in human scale. Who says all life in the universe is the same size as us?
  - jerf 6y ago
    All life in the universe faces the same kinetic energy equations to cross the stars.
    - hypertele-Xii 6y ago
      And if the stars are the equivalent of our atoms to a much larger form of life, what would it's nanotech look like to us?
    - ceejayoz 6y ago
      Probably not the same energy availability, though.
- darthnebula 6y ago
  You're making a lot of assumptions here and basing it on the limited knowledge of a specifies that has failed to make any significant strides into exploring anything other than its own solar system.
  - cogman10 6y ago
    There's an easy answer that coincides with our current understanding of physics. Then there is "Aliens have discovered tech that makes it easier for them to fling a half mile long object vs a satellite sized object across the stars at a relatively slow speed." Sorry if I take "explosion makes rock go far" as being the more plausible explanation than "Aliens want to wait a million years for a brief glimpse at a distant solar system".
    - AnIdiotOnTheNet 6y ago
      To be fair, there is no need for the probe to have been designed for a mission to our star system. It could be that it was a craft meant for something else entirely that left its star system, like our Voyager probes have, and drifted for eons before happening to pass through our star system and be observed. Of course, that is still less likely than some unusual rock doing the same thing.
      - cogman10 6y ago
        Sure, just a bunch of energy for such a large object. "To see if they can" may very well be a reason, but that doesn't seem likely for a species that advances far enough to be able to accomplish such an achievement.
        deleted 6y ago
        [deleted]
    - TeMPOraL 6y ago
      It's not the size/volume that matters, but the mass. Even with our limited science and technology, we have designs for interplanetary ships that drag hundreds of meters of radiator surface with them. It's not hard to imagine - and it has been imagined many times - a ship that consists of a core with a gigawatt-range powerplant, reaction mass, efficient engines, and kilometer-long radiators to dump the powerplant heat into space. If anything, based on our knowledge and assuming no magitech breakthroughs in space propulsion, you should expect interstellar ships to be large but light, maximizing surface area while minimizing mass.
- Method-X 6y ago
  I think one theory is that it’s a huge “light sail” (hence the size). Just what I heard; no idea if this has any merit.
- dbqpdb 6y ago
  The object was actually in the rest frame of our local patch of the galaxy, so in essence, we came to it via our motion about the center of the galaxy.
- spaetzleesser 6y ago
  I don't think this was an alien probe but the size argument is not convincing to me. I would think that if you want to design a probe that can keep going for very long time spans and distances it would have to be big and work more like a factory that can constantly refresh its parts. Devices of the size of our satellites aren't and probably can't be designed to last thousands or millions of years. Something bigger on the other hand can be designed that way.
- arethuza 6y ago
  A size 1000m x 150m seems pretty small for something that would have taken tens of thousands of years to get to our system.
- throwaway316943 6y ago
  The specific reason he contends it may be an alien artifact is that he believes its characteristics match the profile of a light sail: 1) its shape may actually be more like a pancake than a cigar, a crumpled light sail would match this 2) it showed unexpected acceleration away from the Sun without outgassing. 3) its velocity is very close to the mean motion of our local stellar neighborhood, if you needed to drop a solar sail after deceleration so that it would be hard to work out what system you came from then this would be the velocity to do it at.
darthnebula 6y ago
Can it be proven that it is not an alien probe?
- eigenschwarz 6y ago
  Can you prove I'm not God?
  - Koshkin 6y ago
    There are no gods (not on HN anyway).
- simonh 6y ago
  I can't prove you're not an alien infiltrator either, but I'm not about to write a book about it.
  - Koshkin 6y ago
    > I can't prove This is a good reason enough for some people to write a book for a general audience!
- cogman10 6y ago
  Can it be proven that there's not a teapot in the asteroid belt? Extraordinary claims required extraordinary evidence. A massive rock being hurled to by a supernova to our solar system is far more likely than advanced aliens dumping a ton of future tech to get this huge thing into our solar system for a split second. Why? Because, it would cost a lot of energy, something I doubt an advanced race would spend. Further, an advanced race that wants to probe us wouldn't need such a huge object, it's far easier to observe from a far (think, james webb telescope but better). Sure, hard to know what aliens are thinking, but it just seems incredibly unlikely they are thinking "Let's build this half mile long space probe for a glimpse of a distant solar system and send it off for a million year journey". A star exploding and sending a bunch of mass our direction is far more likely. Why? because we know that happens relatively frequently.
aaron695 6y ago
> Out of my network of ~200 astronomers/physicists, I haven't heard one person support the idea that this is an alien probe. I've heard little to nothing in any media articles of anyone supporting alternatives. Is it once a year these are thought to come through, or 100 times a year? Do we get things that are 100 times smaller at 100 times the rate? If people won't make a public call, then lets run with aliens. I was a fan of it's not interstellar, just more fake 'life on Venus' science, but reading some journal articles[1], it seems like it is expected. But it's been hard to work that out. [1] Realistic Detectability of Close Interstellar Comets https://iopscience.iop.org/article/10.3847/0004-637X/825/1/51 https://iopscience.iop.org/article/10.3847/0004-637X/825/1/5...

cogman10 6y ago

And why would it be? It was HUGE. Why on earth would aliens design a probe so large? It would take a ton of energy to make it to our solar system (like, a star exploding... hmmm..). If aliens have probed us, I DOUBT we would have actually noticed them. Because, likely the probe would be about the size of one of our satellites and maybe even a lot smaller to cut down on the amount of energy needed to get them here.

hypertele-Xii 6y ago
Size is so relative. You're thinking in human scale. Who says all life in the universe is the same size as us?
- jerf 6y ago
  All life in the universe faces the same kinetic energy equations to cross the stars.
  - hypertele-Xii 6y ago
    And if the stars are the equivalent of our atoms to a much larger form of life, what would it's nanotech look like to us?
  - ceejayoz 6y ago
    Probably not the same energy availability, though.
darthnebula 6y ago
You're making a lot of assumptions here and basing it on the limited knowledge of a specifies that has failed to make any significant strides into exploring anything other than its own solar system.
- cogman10 6y ago
  There's an easy answer that coincides with our current understanding of physics. Then there is "Aliens have discovered tech that makes it easier for them to fling a half mile long object vs a satellite sized object across the stars at a relatively slow speed." Sorry if I take "explosion makes rock go far" as being the more plausible explanation than "Aliens want to wait a million years for a brief glimpse at a distant solar system".
  - AnIdiotOnTheNet 6y ago
    To be fair, there is no need for the probe to have been designed for a mission to our star system. It could be that it was a craft meant for something else entirely that left its star system, like our Voyager probes have, and drifted for eons before happening to pass through our star system and be observed. Of course, that is still less likely than some unusual rock doing the same thing.
    - cogman10 6y ago
      Sure, just a bunch of energy for such a large object. "To see if they can" may very well be a reason, but that doesn't seem likely for a species that advances far enough to be able to accomplish such an achievement.
      - deleted 6y ago
        [deleted]
  - TeMPOraL 6y ago
    It's not the size/volume that matters, but the mass. Even with our limited science and technology, we have designs for interplanetary ships that drag hundreds of meters of radiator surface with them. It's not hard to imagine - and it has been imagined many times - a ship that consists of a core with a gigawatt-range powerplant, reaction mass, efficient engines, and kilometer-long radiators to dump the powerplant heat into space. If anything, based on our knowledge and assuming no magitech breakthroughs in space propulsion, you should expect interstellar ships to be large but light, maximizing surface area while minimizing mass.
Method-X 6y ago
I think one theory is that it’s a huge “light sail” (hence the size). Just what I heard; no idea if this has any merit.
dbqpdb 6y ago
The object was actually in the rest frame of our local patch of the galaxy, so in essence, we came to it via our motion about the center of the galaxy.
spaetzleesser 6y ago
I don't think this was an alien probe but the size argument is not convincing to me. I would think that if you want to design a probe that can keep going for very long time spans and distances it would have to be big and work more like a factory that can constantly refresh its parts. Devices of the size of our satellites aren't and probably can't be designed to last thousands or millions of years. Something bigger on the other hand can be designed that way.
arethuza 6y ago
A size 1000m x 150m seems pretty small for something that would have taken tens of thousands of years to get to our system.
throwaway316943 6y ago
The specific reason he contends it may be an alien artifact is that he believes its characteristics match the profile of a light sail: 1) its shape may actually be more like a pancake than a cigar, a crumpled light sail would match this 2) it showed unexpected acceleration away from the Sun without outgassing. 3) its velocity is very close to the mean motion of our local stellar neighborhood, if you needed to drop a solar sail after deceleration so that it would be hard to work out what system you came from then this would be the velocity to do it at.

darthnebula 6y ago

Can it be proven that it is not an alien probe?

eigenschwarz 6y ago
Can you prove I'm not God?
- Koshkin 6y ago
  There are no gods (not on HN anyway).
simonh 6y ago
I can't prove you're not an alien infiltrator either, but I'm not about to write a book about it.
- Koshkin 6y ago
  > I can't prove This is a good reason enough for some people to write a book for a general audience!
cogman10 6y ago
Can it be proven that there's not a teapot in the asteroid belt? Extraordinary claims required extraordinary evidence. A massive rock being hurled to by a supernova to our solar system is far more likely than advanced aliens dumping a ton of future tech to get this huge thing into our solar system for a split second. Why? Because, it would cost a lot of energy, something I doubt an advanced race would spend. Further, an advanced race that wants to probe us wouldn't need such a huge object, it's far easier to observe from a far (think, james webb telescope but better). Sure, hard to know what aliens are thinking, but it just seems incredibly unlikely they are thinking "Let's build this half mile long space probe for a glimpse of a distant solar system and send it off for a million year journey". A star exploding and sending a bunch of mass our direction is far more likely. Why? because we know that happens relatively frequently.

aaron695 6y ago

> Out of my network of ~200 astronomers/physicists, I haven't heard one person support the idea that this is an alien probe. I've heard little to nothing in any media articles of anyone supporting alternatives. Is it once a year these are thought to come through, or 100 times a year? Do we get things that are 100 times smaller at 100 times the rate? If people won't make a public call, then lets run with aliens. I was a fan of it's not interstellar, just more fake 'life on Venus' science, but reading some journal articles[1], it seems like it is expected. But it's been hard to work that out. [1] Realistic Detectability of Close Interstellar Comets https://iopscience.iop.org/article/10.3847/0004-637X/825/1/51 https://iopscience.iop.org/article/10.3847/0004-637X/825/1/5...