This
week’s show was with Dr. Abraham (Avi) Loeb, the Harvard astronomer who has
caused a stir by suggesting that a strange object that was spotted in the Solar
System was, in fact, an alien artifact. Given its attributes, he says that it
was something manufacture more than ten thousand years ago. You can listen to
our discussion here:
https://www.spreaker.com/episode/43152043
For
those interested, we did talk about the age of the artifact and the idea that
there 
Dr. Abraham Loeb
would be others out there. Avi, in his book, and on the show, talked
about astro-archaeology, which is searching for artifacts created by other
intelligence species as a better way to discover other civilizations than SETI.
These alien civilizations might be long gone, but their artifacts are still out
there. He thought that they might be rare but not unique. He suggested ways for
us to prepare for discovery of the next one, gathering additional data about
it. You can find his book here:
I
did mention a science fiction novel (The Rat Trap) that I had written,
literally, decades ago about an alien race that sent out probes, searching for
other intelligence races. They determined the level of development by the
capabilities the civilizations exhibited. A race that had some form of space
flight would be able to intercept their artifact and those that managed to
penetrate into the craft, displayed a higher intelligence. It was, in one form,
an intelligence test.
Although
many had suggested that the artifact was associated with Vega, a star some 25
light years from Earth, that seems to have been a misunderstanding. Avi explains
that situation and suggests that there really isn’t a good way to track the
object back to its point of origin.
We
also discussed whether a spacefaring race would be interested in the Earth. Avi
suggested, given our propensity for tribal warfare, that we weren’t displaying
much in the way of intelligence. I thought that any spacefaring race that found
Earth would be interested in us from a scientific point of view, watching our
societal evolution (or based on what has been happening, de-evolution). He
thought they would wait until we were more enlightened.
Eventually,
we did talk about UFOs and what he’d like to see in the way of evidence. In
this case, he’d like to take the witnesses out of the equation and rely on
instrumentality exclusively. I did mention the MADAR network to him but he
seemed to want something that was much more sophisticated, which, I think meant
something much more expensive and with the best equipment. He wanted all the
data gathered by the instruments without any human participation.
We
never did talk about the problems of interstellar flight, which I see as the
major hurtle here. I do believe we had a very interesting discussion about the
alien artifact, interstellar communication, and what we might expect in the
future.
While
I didn’t get all the questions asked, I think I did get answers to all of them.
For example, one of them was about RF emissions from the artifact. Given his
belief that it was so old and therefore didn’t hold any sort of crew, there
wasn’t much chance of any sort of signal from it. But, of course, no one
checked for any RF signal. However, it also seems that the next time this
happens, they’ll be better prepared to observe it.
Next
week, I’ll be talking with Don Schmitt. The plan is to look at the state of
Ufology and where it needs to go.
About the claim of Dr. Loeb that Oumuamua took more than 10,000 years to go cross our solar system.
ReplyDeleteThis depends on the meaning of the term "solar system". "Solar system" is supposed to mean the gravitational bound system of our Sun and the objects around it.
We unwashed public assumes this is out to Pluto, which is about 30-50 AU. One AU or astronomical unit is 1/63241 light years. So, Pluto is at most at .0008 light year away.
Oumuamua is listed as going at a speed of 5.55 AU/year. This means it took at most (50 AU) *2 / (5.55 AU/year)= 18 years to pass through this definition of solar system. We multiplied this by 2.0 because the object had an inbound path and an outbound path, so this is at most 50 AU plus 50 AU.
Where did Dr. Loeb get >10,000 years? He defined "solar system" differently than we understand it.
The outermost gravitationally bound objects are the hypothesized Oort cloud objects. The outer most limit is guessed to be 50,000 AU to 100,000 AU. But the balance of the gravitational field of our Sun with the stars around it may extend to 125,000 AU.
So, this is 50,000 AU *2 /5.55 AU/year=18,000 years. Or maybe the extreme upper limit, up to 125,000 AU*2/5.55 AU/year=45,000 years. Again, we had to multiply by 2 for inbound and outbound passage.
So, he is right, although not in the spirit the public understands.
It was mentioned that our radio broadcasts from 100 years ago would have grown into a huge circle of intersections with other stars. The problem with this is that the Earth radio and tv signals diminish by 1/distance squared (the inverse square law). Thus over light years of distance, the signal strength will have diminish to an extremely low level that would require a huge antenna to pick it up. So, what is the limit to detecting our radio signals? Take a standard UHF TV broadcast antenna at 5,000,000 watts broadcast power beaming omnidirectionally. By the time the signal reaches Alpha Centauri (4.37 light years= 4.13E16 meters), it has gone from 5,000,000 watts to 3.0E-27 watts (using a 1 square meter detector/antenna). This is a super tiny amount of power to detect! Let's say you have a giant detector/antenna (10000 square km area, a 100km by 100km antenna), the signal goes up to 3.0E-17 Watts. The signal from Voyager 1 is 1.0E-18 watts as measured at Earth. Of course the farther away the star, the larger the antenna is needed. Seth Shostak would say no problem since they are advanced aliens.
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