17 pictures that show how mind-bogglingly large the Universe is

[BlueGreenLady]

https://bigthink.com/starts-with-a-bang/how-large-universe/

[secondwind]

1. Fascinating stuff! Bookmarked for later enjoyment.

[progree]

2. If the distance to the sun was scaled down to just one inch --

Last edited Wed Jun 1, 2022, 04:05 AM - Edit history (1)

A light year would be one mile away

The distance to the nearest star (Proxima Centuari) would be 4.25 miles away

The distance to the nearest galaxy (Andromeda Galaxy) would be 2.54 million miles away

And we've only just begun

https://slate.com/technology/2012/06/bafact-math-give-him-an-inch-and-he-ll-take-a-light-year.html

[Cheezoholic]

3. 42 n/t

[renate]

4. Wow, that article was amazing!

Thank you so much for sharing it!!

[IcyPeas]

5. My brain cannot even imagine....

The size of our visible Universe (yellow), along with the amount we can reach (magenta). The limit of the visible Universe is 46.1 billion light-years, as that’s the limit of how far away an object that emitted light that would just be reaching us today would be after expanding away from us for 13.8 billion years. However, beyond about 18 billion light-years, we can never access a galaxy even if we traveled towards it at the speed of light. Beyond the limits of the observable Universe lies more Universe, up until the limits imposed by wherever inflation didn’t end at the same time it did where our hot Big Bang occurred. That limit, if it exists, has not been discovered.

[Easterncedar]

6. Thanks!

I love starting the day with my mind blown!

[Irish_Dem]

7. Doesn't seem possible that we are the only sentient life.

When you look at the size of the universe.

[CloudWatcher]

12. It's likely that we're alone

If we're not alone, then where are all the aliens? Why hasn't SETI found anything?

This is likely way more than you wanted to read, but I loved this paper that (I believe) did a great job explaining why we're not overrun with aliens. Some math, but nothing too explosive if you've had some statistics.

Dissolving the Fermi Paradox: https://arxiv.org/pdf/1806.02404.pdf

Abstract

The Fermi paradox is the conflict between an expectation of a high ex ante probability of intelligent life elsewhere in the universe and the apparently lifeless universe we in fact observe.

The expectation that the universe should be teeming with intelligent life is linked to models like the Drake equation, which suggest that even if the probability of intelligent life developing at a given site is small, the sheer multitude of possible sites should nonetheless yield a large number of potentially observable civilizations.

We show that this conflict arises from the use of Drake-like equations, which implicitly assume certainty regarding highly uncertain parameters. We examine these parameters, incorporating models of chemical and genetic transitions on paths to the origin of life, and show that extant scientific knowledge corresponds to uncertainties that span multiple orders of magnitude. This makes a stark difference.

When the model is recast to represent realistic distributions of uncertainty, we find a substantial ex ante probability of there being no other intelligent life in our observable universe, and thus that there should be little surprise when we fail to detect any signs of it.

This result dissolves the Fermi paradox, and in doing so removes any need to invoke speculative mechanisms by which civilizations would inevitably fail to have observable effects upon the universe.

[Irish_Dem]

13. The Fermi paradox is not resolved?

https://forum.effectivealtruism.org/posts/kvZshdx5FzTPjyhxG/the-fermi-paradox-has-not-been-dissolved

Conclusion
In this essay I have argued that the analysis presented by Sandberg et al. concerning the dissolution of the Fermi paradox is multiply flawed. First, the approach of multiplying many parameter intervals with an upper bound at one, but no corresponding lower bound, predisposes the resulting distribution of the number of alien civilisations to exhibit a very long negative tail, which drives the reported result. Second, the method used to estimate the distribution of the parameter fl is insufficiently justified, and the main result of the paper disappears if this parameter is modelled in the same way as the other parameters. Furthermore, the very low estimates of fl and fi reported in the literature review as supporting evidence are mostly misstated from their sources, and are based on vague speculation rather than specific scientific evidence. Third, an alternative modelling approach which incorporates the evidence of the early emergence of life on Earth, and also makes slightly different assumptions regarding the other parameters of the Drake equation, finds a much lower probability that Earth is unique in the Milky Way, and a negligible chance of being alone in the universe. Overall, while Sandberg et al. have made a significant contribution to the study of the Fermi Paradox and the Drake equation by illustrating how computational methods can be used to construct distributions for the probability of various numbers of alien civilisations, I do not believe they have succeeded in showing that the probability of Earth being alone is sufficiently high so as to dissolve the Fermi paradox. Indeed, I present two different set of parameters which yield a negligible probability of Earth being alone in the universe, and hence insomuch as the estimated number of alien civilisations depends crucially on the chosen modelling assumptions, the Fermi Paradox remains very much an open question.

[Irish_Dem]

14. PS

In addition to the math problems in Sandberg et al, there are some questionable assumptions.

1. What is their definition of intelligent life?
Perhaps their use of chemical and genetic markers of life are incorrect for life on other planets.

2. How do we know that other life has not visited this planet? We can assume they would be highly intelligent if they can conduct interstellar travel. Therefore they would recognize Earth's inhabitants as highly primitive, ignorant, intolerant of others and violent. Why in the heck would they announce their presence? Would be foolish of them.

3. On a personal note, I am a military brat, grew up in the Air Force with a Dad who flew combat in three wars. Pilots since WWII have been reporting seeing mysterious aircraft not flying in ways possible with current technology.

[hlthe2b]

8. Yes. And how relatively small is earth. I reealized that for the first time after tracking the miles

I have walked (at least those that I have tracked on Fitbit since 2014) =14,285 miles. The earth's circumference is approximately 24, 901 miles, so I have more than walked halfway around the earth. That's amazing to me. I hope to make the whole thing.

[niyad]

9. KNR and bookmarking. For later.

[Blue Owl]

10. The pale blue dot...

It's such a miracle that this planet and the life on it even exists...

And so depressing to consider the smallness of the minds that wrestle for control of its destiny...

[CloudWatcher]

11. Zooming about the universe

If you like this, you might like these:

The (original?) Powers of Ten short from 1977:

And an updated version by CPG Grey (2021)