71–80 of 142 posts
Earlier quoted context omitted.
The fossil record. There is little evidence of very complex animal life before about 541 million years ago, which is when the Cambrian explosion begun.
When you say very little, do you mean none, or there is some questionable evidence? I'm genuinely curious
Suppose a planet like this had non intelligent megafauna life. How could we detect this?
That spectrum is so noisy. How can they infer the blue fit from the (noisy) white points? The data look almost consistent with flat (no detection). And even if there is a detection, it looks like many other models could potentially fit the data...
By having a detailed model, and modern probabilistic techniques:
The planet’s terminator is modelled as a plane-parallel atmosphere in hydrostatic equilibrium, with uniform chemical composition. The chemical abundances and pressure-temperature (P-T) profile are free parameters in the model. The retrieval framework follows a free chemistry approach, whereby the individual mixing ratio of each chemical species is a free parameter.... Our canonical model comprises of 22 free parameters overall: 11 corresponding to the individual mixing ra- tios of the above chemical species, 6 for the P-T profile, 4 for the clouds/hazes and 1 for the reference pressure Pref , defined as the pressure at a fixed planetary radius of 2.61 R⊕. The Bayesian inference and parameter estimation is conducted using the MultiNest nested sam- pling algorithm (Feroz et al. 2009) implemented through PyMultiNest.
(Sections 2.4 and 3.1 from https://stsci-opo.org/STScI-01HA2G716KS9YGAGVY1WBVFJ8Y.pdf)
> And even if there is a detection, it looks like many other models could potentially fit the data...
Name three.
Earlier quoted context omitted.
What's also crazy is if we did send a rover over there to hunt for life, and they found it, we'd have to wait 125 years to hear the result. We all sit around knowing to listen to the skies sometime in October of 2185 to hear if the rover found life within the first month of its landing. If we ever send a team to live there, we'd hear broadcasts of their lives from 125 years prior. A real portal in time - so cool.
Even worse if we are still limited by Newtonian dynamics it will take thousands of years for a probe to reach there. The rocket equation is a harsh mistress. In practical terms we will never visit that world without completely upending physics as we know it.
120 light years away. Time to get the ufo tech out already.
is Faster Than Light travel even possible? I'm asking in a serious way. I have always read that its impossible, at least within our current knowledge. the only semi-plausible theory I've ever heard is that Blackholes might one day yield some way of traveling quickly across the universe but nobody has shown anything substantiated around that or anything else.
120 light years away. Time to get the ufo tech out already.
is Faster Than Light travel even possible? I'm asking in a serious way. I have always read that its impossible, at least within our current knowledge. the only semi-plausible theory I've ever heard is that Blackholes might one day yield some way of traveling quickly across the universe but nobody has shown anything substantiated around that or anything else.
Earlier quoted context omitted.
is Faster Than Light travel even possible? I'm asking in a serious way. I have always read that its impossible, at least within our current knowledge. the only semi-plausible theory I've ever heard is that Blackholes might one day yield some way of traveling quickly across the universe but nobody has shown anything substantiated around that or anything else.
The ufos have to come from somewhere, right?
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Not certain at all, it’s based on last universal common ancestor estimates(LUCA) and supported by (lack of) fossil record.
> it’s based on last universal common ancestor estimates(LUCA) and supported by (lack of) fossil record. I thought the Cambrian Explosion's fossil record was pretty sizeable - in fact, it's named after the place where the fossil layer was first discovered. I didn't know it was related to a common ancestor. Are you thinking of something else or am I missing something major?
What sort of observation or measurement would allow us to identify life on an exoplanet?
Earlier quoted context omitted.
What's also crazy is if we did send a rover over there to hunt for life, and they found it, we'd have to wait 125 years to hear the result. We all sit around knowing to listen to the skies sometime in October of 2185 to hear if the rover found life within the first month of its landing. If we ever send a team to live there, we'd hear broadcasts of their lives from 125 years prior. A real portal in time - so cool.
How do you get the rover there? It would take thousands of years. Or maybe millions of years? With the current tech