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Have Aliens Found Us? A Harvard Astronomer on the Mysterious Interstellar Object 'Oumuamua (newyorker.com)
On October 19, 2017, astronomers at the University of Hawaii spotted a strange object travelling through our solar system, which they later described as "a red and extremely elongated asteroid." It was the first interstellar object to be detected within our solar system; the scientists named it 'Oumuamua, the Hawaiian word for a scout or messenger. The following October, Avi Loeb, the chair of Harvard's astronomy department, co-wrote a paper (with a Harvard postdoctoral fellow, Shmuel Bialy) that examined 'Oumuamua's "peculiar acceleration" and suggested that the object "may be a fully operational probe sent intentionally to Earth's vicinity by an alien civilization." Loeb has long been interested in the search for extraterrestrial life, and he recently made further headlines by suggesting that we might communicate with the civilization that sent the probe.
Isaac Chotiner of The New Yorker has interviewed Loeb, who was frustrated that scientists saw 'Oumuamua too late in its journey to photograph the object. "My motivation for writing the paper is to alert the community to pay a lot more attention to the next visitor," he told Chotiner. An excerpt from the interview: The New Yorker: Your explanation of why 'Oumuamua might be an interstellar probe may be hard for laypeople to understand. Why might this be the case, beyond the fact that lots of things are possible?
Loeb: There is a Scientific American article I wrote where I summarized six strange facts about 'Oumuamua. The first one is that we didn't expect this object to exist in the first place. We see the solar system and we can calculate at what rate it ejected rocks during its history. And if we assume all planetary systems around other stars are doing the same thing, we can figure out what the population of interstellar objects should be. That calculation results in a lot of possibilities, but the range is much less than needed to explain the discovery of 'Oumuamua.
There is another peculiar fact about this object. When you look at all the stars in the vicinity of the sun, they move relative to the sun, the sun moves relative to them, but only one in five hundred stars in that frame is moving as slow as 'Oumuamua. You would expect that most rocks would move roughly at the speed of the star they came from. If this object came from another star, that star would have to be very special.
[...]The New Yorker: Hold on. "'Not where is the lack of evidence so that I can fit in any hypothesis that I like?' " [Bailer-Jones, of the Max Planck Institute for Astronomy, in Heidelberg, Germany, has identified four possible home stars for 'Oumuamua, and was asked to respond to Loeb's light-sail theory by NBC.]
Loeb: Well, it's exactly the approach that I took. I approached this with a scientific mind, like I approach any other problem in astronomy or science that I work on. The point is that we follow the evidence, and the evidence in this particular case is that there are six peculiar facts. And one of these facts is that it deviated from an orbit shaped by gravity while not showing any of the telltale signs of cometary outgassing activity. So we don't see the gas around it, we don't see the cometary tail. It has an extreme shape that we have never seen before in either asteroids or comets. We know that we couldn't detect any heat from it and that it's much more shiny, by a factor of ten, than a typical asteroid or comet. All of these are facts. I am following the facts.
Last year, I wrote a paper about cosmology where there was an unusual result, which showed that perhaps the gas in the universe was much colder than we expected. And so we postulated that maybe dark matter has some property that makes the gas cooler. And nobody cares, nobody is worried about it, no one says it is not science. Everyone says that is mainstream -- to consider dark matter, a substance we have never seen. That's completely fine. It doesn't bother anyone. But when you mention the possibility that there could be equipment out there that is coming from another civilization -- which, to my mind, is much less speculative, because we have already sent things into space -- then that is regarded as unscientific. But we didn't just invent this thing out of thin air. The reason we were driven to put in that sentence was because of the evidence, because of the facts. If someone else has a better explanation, they should write a paper about it rather than just saying what you said.
Isaac Chotiner of The New Yorker has interviewed Loeb, who was frustrated that scientists saw 'Oumuamua too late in its journey to photograph the object. "My motivation for writing the paper is to alert the community to pay a lot more attention to the next visitor," he told Chotiner. An excerpt from the interview: The New Yorker: Your explanation of why 'Oumuamua might be an interstellar probe may be hard for laypeople to understand. Why might this be the case, beyond the fact that lots of things are possible?
Loeb: There is a Scientific American article I wrote where I summarized six strange facts about 'Oumuamua. The first one is that we didn't expect this object to exist in the first place. We see the solar system and we can calculate at what rate it ejected rocks during its history. And if we assume all planetary systems around other stars are doing the same thing, we can figure out what the population of interstellar objects should be. That calculation results in a lot of possibilities, but the range is much less than needed to explain the discovery of 'Oumuamua.
There is another peculiar fact about this object. When you look at all the stars in the vicinity of the sun, they move relative to the sun, the sun moves relative to them, but only one in five hundred stars in that frame is moving as slow as 'Oumuamua. You would expect that most rocks would move roughly at the speed of the star they came from. If this object came from another star, that star would have to be very special.
[...]The New Yorker: Hold on. "'Not where is the lack of evidence so that I can fit in any hypothesis that I like?' " [Bailer-Jones, of the Max Planck Institute for Astronomy, in Heidelberg, Germany, has identified four possible home stars for 'Oumuamua, and was asked to respond to Loeb's light-sail theory by NBC.]
Loeb: Well, it's exactly the approach that I took. I approached this with a scientific mind, like I approach any other problem in astronomy or science that I work on. The point is that we follow the evidence, and the evidence in this particular case is that there are six peculiar facts. And one of these facts is that it deviated from an orbit shaped by gravity while not showing any of the telltale signs of cometary outgassing activity. So we don't see the gas around it, we don't see the cometary tail. It has an extreme shape that we have never seen before in either asteroids or comets. We know that we couldn't detect any heat from it and that it's much more shiny, by a factor of ten, than a typical asteroid or comet. All of these are facts. I am following the facts.
Last year, I wrote a paper about cosmology where there was an unusual result, which showed that perhaps the gas in the universe was much colder than we expected. And so we postulated that maybe dark matter has some property that makes the gas cooler. And nobody cares, nobody is worried about it, no one says it is not science. Everyone says that is mainstream -- to consider dark matter, a substance we have never seen. That's completely fine. It doesn't bother anyone. But when you mention the possibility that there could be equipment out there that is coming from another civilization -- which, to my mind, is much less speculative, because we have already sent things into space -- then that is regarded as unscientific. But we didn't just invent this thing out of thin air. The reason we were driven to put in that sentence was because of the evidence, because of the facts. If someone else has a better explanation, they should write a paper about it rather than just saying what you said.
The opposite of science is believe. You can believe all you want, but to know something objectively you need science. Science is the method to develop hypotheses, try to falsify it, and improve your theories. What we know is the potential weight of the object, the shape -- well only very, very roughly -- all the drawings are artistic, so it looks most likely differently. Therefore, science concluded that it is an extra solar object, which is most likely not artificial. We do not know enough to come to another conclusion. We can believe of course that it is something else, but that is believe and speculation.
All those probes that we send to planets should be designed with a longer operational life.
Yup, that's actually already the case. How do you think the mars rovers managed to stay so long in operation ?
Engineer plan for the worse, put as wide margin as possible, and try to manage to meet the primary mission even in the case of giant string of unluck and problems.
(Everything redundant, and other such backups - well within the limits of weight of what the launcher can put into orbit up there, of course).
Often, mission gets lucky, there's no catastrophic event happening and the probe turns out to be useful for much longer than initially planned (there are still at least 1 backup/redundant part working even after the end of the primary mission.
When the primary mission is over they start a secondary mission:
That's already the case : as long as it's still miraculously working, keep using it!
See: New Horizon's recent flyby of Ultima Thule, and the pictures of it that the probe will be uploading to Earth over the next couple of years. (Interplanetary bandwidth sucks...)
The existence of that object wasn't even known back when the mission was planned, but once it turned out that New Horizon successfully completed its primary mission (Pluto) and still had enough functional systems to continue, it turned out the contact binary (that was discovered a couple of years ago) was a perfect target that happened to be within reach of the probe.
long term observation which includes special unexpected things like oumouamua
Planning specifically for extra planetary things like 'oumuamua is asinine :
- You can't *plan* for *unexpected* object. See Ultima Thule above, it's wasn't even known until recently. You usually have a more opportunistic approach: given the remaining capability of the probe at the end of its primary mission, what are the possibility that present themselves ? Are there targets that are on the trajectory of the probe (baring some micro correction that could still be achieved with whatever left-over capability is available) ? :
What you're basically asking is aiming a probe 15 years in advance at some empty spot, and hope that 11 years later an unexpected extra solar object will suddenly pop-up and luckily happen to go through said empty spot at the exact right time....
and speaking of time
- Space is extremely vast and mostly empty (on a human scale. Of course on the grand scale of a galaxy we're still a pretty busy sector). You might be launching thousands to hundreds of thousands (*) of probes before another such extra solar visit even happen. ...and the probes that happen to be space borne at the moment might be at the wrong place, which leads to :
- Extra solar objects are weird (simply because they didn't form together with our solar system, by definition) and thus will have completely weird trajectory not even in the same rotational direction and not in the same plan to begin with (See 3d tracing of the path 'oumuamua. It's almost perpendicular to the plan of our solar system).
Also, changing trajectory costs big amount of energy and fuel/mass, which in turn is heavy and would require even more prohibitively powerful rockets to launch. To be launchable with currently existing rocket technology, probes end up limited to only small corrections/burns (and use free gravity assistance as much as possible), they can only change trajectory slightly.
Life isn't like in a video game where space ship can jump hyperspace portals all-over the place.
Thus, there wouldn't be a practical way to ask a probe to veer completely of course and head for a completely different and unusual spot where a recently spotted extra solar object is expected to show up.
With the current state of tech (only relatively short distance at which we can sport interesting targets, limited range of probes, etc.) we can't do much for ob
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