Astrophysicist Believes Technologically-Advanced Species Extinguish Themselves (sciencedaily.com)

Why haven't we heard from intelligent life elsewhere in the universe? wisebabo writes: In the Science Daily article "Where is everybody? The Implications of Cosmic Silence," the retired astrophysicist Daniel Whitmire explains that using the principle of mediocracy (a statistical notion that says, in the absence of more data, that your one data point is likely to be "average"), that not only are we the first intelligent life on earth but that we will likely be the only (and thus the last) intelligent life on this planet... Unfortunately that isn't the worst of it.

Coupled with the "Great Silence", it implies that the reason we haven't heard from anyone is that intelligent life, when it happens anywhere else in the universe, doesn't last and when it does it flames out quickly and takes the biosphere with it (preventing any other intelligent life from reappearing. Sorry dolphins!). While this is depressing in a very deep sense both cosmically (no Star Trek/Wars/Valerian universes filled with alien civilizations) and locally (we're going to wipe ourselves out, and soon) it is perhaps understandable given our current progress towards reproducing the conditions of the greatest extinction event in earth's history.
That last link (reprinting a New York Times opinion piece) cites the "Great Dying" of 90% of all land-based life in 252 million B.C., which is believed to have been triggered by "gigantic emissions of carbon dioxide from volcanoes that erupted across a vast swath of Siberia." But if we're not headed to the same inexorable doom, that raises an inevitable follow-up question.

If intelligence-driven extinction doesn't explain this great cosmic silence, then what does? Why hasn't our species heard from other intelligent civilizations elsewhere in the universe?

Comments

TIME is V A S T

[redelm]

Not only is space incomprehensibly vast, but so is time. 16 billion years sounds easy to say, but if an intelligent species only broadcasts "clear", identifiable uncompressed unencrypted radio for ~100 years, then we have only 1 in 160 million chances of finding them with something like SETI.

Galactic internet vs crystal radios

[John Jorsett]

For all we know, the universe is all chatting with each other via quantum entanglement or something even more advanced, and we're off in the corner thwacking our electromagnetic equipment on the side saying, "Is this thing on? Where is everybody?"

We could prevent the Great Dying

[Solandri]

cites the "Great Dying" of 90% of all land-based life in 252 million B.C., which is believed to have been triggered by "gigantic emissions of carbon dioxide from volcanoes that erupted across a vast swath of Siberia.

Our technology is to the point where we could prevent a recurrence of the Great Dying. All you have to do is unshackle your mind from the popular notion that the only solution to CO2 emissions is passive (reducing emissions via renewable energy sources).

CO2 (and water) are popular end-products for exothermic chemical processes (e.g. burning gasoline, cellular respiration) because it sits at an extremely low energy potential. That is, chemical processes which result in CO2 give off a lot of energy. To reverse the process, you have to put a lot of energy into the CO2 to break apart the carbon and oxygen atoms.

If you have sufficient energy, you can actively drive that reverse process. Plants do it via photosynthesis, driving it with energy from sunlight. We could do it with nuclear power - generating massive quantities of electricity (more than can reasonably be obtained from solar, wind, hydro) to decompose CO2. Generating sufficient power to offset volcanic emissions of CO2 would be incredibly expensive, but given the alternative (extinction) we're technologically capable of doing it.

The same is true if this push for renewables as the only solution to global warming fails. If renewables can't be developed quickly enough to supplant fossil fuel energy sources and CO2 levels continue to rise, at some point we concede that renewables aren't arresting CO2 levels quickly enough. Then we'll be forced to switch to nuclear power to buy ourselves more time. This is why shuttering operational nuclear plants as Germany is doing is extremely short-sighted. Nuclear is our ultimate trump card. We want to keep it ready in our back pocket as a hedge in case renewable energy can't be rolled out quickly enough.