Last edited Thu Oct 22, 2015, 08:05 AM - Edit history (3)

We can detect only the planets we can detect.

Both of the techniques induce selection bias.

1. The transit method where the planet transits across the face of the star is biased by the closest and largest planets. They have the largest signal. Plus, the larger the orbit, the longer the orbital period. The Kepler spacecraft died only three years into its mission due to gyroscope (reaction wheel) failures. That was just barely enough time to detect an Earth sized planet at an orbit like Earth.

2. The gravity method where a planet does not so much orbit a star as much as they both orbit each other around a common barycenter. This is detectable by small changes in a star's velocity with respect to the planet. The planet pulls on the star which is measurable by Doppler effect on the light coming from the star. The thing is, the closer and larger the planet is, the bigger the Doppler shift.

So both of the major planet detection techniques detect bigger, closer planets more easily than planets like Earth.

One question the Kepler mission did resolve -- the one question it was designed to answer -- is how many Earth like planets in a habitable zone are in the Milky Way galaxy?

The answer was billions, to the best of our data.

The quantitys are unfathomable. As a kid when someone would say something about the "whole" universe, as if it was some sort of shape, I would ask but what is on the other side It is still hard to fathom exactly how space really works.

I think the study is bad science

It is like those folks who claim intelligent life is rare, or unique, in the galaxy... cough! cough! Peter Ward.

Well, that is not what one would expect given the shear numbers. We have a sample of one, so that biases us. But it can bias in one of two ways.

1. The one case is the rule.
2. The one case is the exception.

Both would be likely wrong.

My thinking on intelligent life in the galaxy is that the distances between stars is kind of large. Interstellar travel is a fucking bitch. As a physics graduate, I don't know how one gets around the rocket equation other than matter/anti-matter annihilation, which is in itself a bitch (sorry, Dan Brown). Plus, there's the time dilation when one travels approaching light speed, but that ignores the particles hitting your craft traveling at those speeds. How does one shield such things? Which brings one right smack dab back to the rocket equation.

My thinking is that intelligent life forms may be common or rare, but they will very be likely isolated in their star systems by just the facts of the universe.

My best to you. You do good post.

Michio is too into the woo-woo, and hopelessly self-promotes his string theory so-called inventions. He is not my cup of a substance not entirely unlike tea. Hence Michio Cuckoo.

I am not a big fan of Strings either. It seems like mere mathematical legerdemain. I once played that game (not Strings, but mathematical modeling). It does nothing to lead one to nature, it only leads one to something not entirely unlike nature. Strings make predictions that are not born out by nature. So far.

on edit: BTW, I despise that the iconic first broadcast received by aliens might be I Love Lucy, an absolutely horrible excuse for entertainment. I would prefer the 1938 Orson Welles broadcast of War of the Worlds which has certainly reached out a couple more light decades than fucking Lucy.



Regards.

A single moon large enough to produce tides. That is a major factor in how life as we know it evolved on this planet. They act as a pump to push life from the seas on to the land masses.

No way we can say that a large tidal locked essentially dual planet system is a necessary condition for the development of complex life, but, if it is, then complex life has to be exceedingly rare.

We may have a really big number for rocky planets in the galaxy, but we are also dealing with some very small probability numbers. In terms of our knowledge base, unless their is Physics we don't understand (engineering sufficient to employ worm holes for example) life outside our galaxy is irrelevant to us.

Even with an appropriate planet, evolution is directionless. No reason to think that complex life will eventually develop technology. The dinosaurs had a very long run and never came close.

only lack high and low tides but it should still have waves created from wind and seismic activity so life could still potentially evolve even on a planet without a moon.

last month, and the tides on the Bay of Fundy make ocean waves seem nearly irrelevant. I'm convinced that tidal forces were a major factor in the development of life forms on this planet.

Have you seen the part of the Petitcodiac River known as the Chocolate River flow backwards in Moncton, NB? It's a powerful thing!

find a way to travel back in time.

is eventually travel to enough "Earth like" planets without a single significant moon, and my prediction is that we'll see complex life pretty much only in the seas of those places.

which really help create life.

Now about those deep sea vents? Tides have nothing to do with life
found there.

I'm just saying they were a major force in aiding the development of the complex creatures we have on land, including our own species.