Why Astronomers Are Not Looking for Yellow Planets 

The sad fact is physics has us locked in an unhelpful light cone. Due to the time delay for light to cross the abyss between star systems, we're only ever able to see things as they were several thousand or million years ago. Think about how Earth was in that time frame; we'd look like an empty planet to any other extra-solar civilization, and they'd look much the same to us, presumably.

I forget which recent video I watched (edit: it was Mark Rober's video about his Octopus Maze), but it discussed octopuses (octopi?) being the closest thing to aliens on our planet. The premise is that they broke off from the evolutionary path so long ago, that their level of intelligence and physical abilities are unique compared to all other members of the animal kingdom. To be clear, no one is saying that they are actually aliens, just that they are so incredibly different in every way.

We dont often talk about the effects of gravity on life. I wonder how life would have evolved here under different gravity conditions. Since we are looking for life on other planets with potentially very different gravity we should take into account how gravity affects life and evolution. Life on alien worlds could look so different that we may hardly recognise them as lifeforms.

When i first learned that Terra used to (likely) be purple, i laughed so hard. I think it was some years ago and for some reason i couldn't help but associate it with Grimace (way before the shake craze).

The comment section taught me just as much as the video did, yall are smart af

7:55 to me that is something akin to actual magic! I've always wondered and pondered on the fact we make VitD from sunlight and thought that THAT could be straight out of a SciFi novella!

So, I’ve always loved your videos but last month or so your videos have stepped up a new level of awesome. I’m enjoying the more detailed science! 🤗🤗

Once i learned about Bacteriophages, I couldn't help but be curious about them. Phages are the most abundant thing on earth. They are viruses that transfer info into bacteria. They look like nanotechnology. Something straight out of a sci-fi movie. It makes me wonder, what if certain things are capable of being in different places around space? If not, if they started here, could they transfer to other areas in space? Do they & other viruses play a role in life evolving and adapting?

Thanks so much for creating and sharing this informative video. Great job. Keep it up.

Really enjoying the new videos, been watching since covid but there’s a clear step up with y’all’s recent uploads, well done lol

I wonder at what point the balance of methane and oxygen in the earths atmosphere was just right to light the entire atmosphere on fire

When people tell me the universe was literally DESIGNED for life... I often remind them how hard it is to even get to our own moon. EVERYTHING wants us dead.

❤❤❤ thanks for your wonderful insights and soothing voice

Absolutely brilliant stuff. There is so much to learn.

If I was an intergalactic alien tasked with looking for signs of life? I'd go right to the heart: Sag A* is visible from most points in the Milky Way Galaxy in some way or another, so it seems like a natural rallying point or hub, at least a few light years out.

Astrum you should do a video on abiogensis, like the RNA world hypothese or the panspermia hypothesis

Thank you, Alex! 🦠

Yet another superb video

Amazing content 👌

Great video!! I can't help but giggle about the idea of purple planets though, my silly side just had to ask me: "So are there purple people eaters?" These are really fascinating possibilities. The Nautilus and HabEx are both super exciting too, and I also hope they get approval. We've been wanting - NEEDING - to get some kind of array in place that lets us have an effective "mirror" bigger than the Earth itself, for decades. I'm interested to hear more about Nautilus in particular, I'd imagine that they're going to need some very clever ideas to handle energy needs - an array like that probably wants adjustment to maintain position FAR more frequently than Hubble or Webb. Ion engines might get them into place, but I don't think those are so good for fine adjustment, correct? So there would need to be rocket thrusters of some sort? Which then implies the need for a mass of fuel, and the further problem of running OUT of fuel at some future point. But I wonder if we finally have something other than rockets for that task (that is also cost effective and sturdy). So much to be excited about!

This has never been a puzzle to anyone, even remotely intelligent. It is obvious that the egg came first. The chicken evolved from a dinosaur, THAT LAID EGGS.

Super explanation.

Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” - Arthur C Clerk.

I couldn't resist . At 01:20 "Is There Anybody Out There". Pink, maybe? ;-)

Please could you do a video on radiosynthesis and the possibility of life utilising this outside of earth. Your video's are amazing, thank you.

The problem with halophilic archaea is that independent of their astonishing ability to survive under extreme conditions like space, they need a warm liquid brine pool (~35°C), usually on the 4°C cold seafloor, to thrive on chemosynthesis (hydrogen sulfide, methane). Higher eukaryotes like deep sea molluscs live in symbiosis with the halophilic archaea exclusively on the border of the brine pool whose alkaline water is deadly for any aerobic lifeform.

My daughter is six and when she overheard me starting this video she told me she loved this channel ☺️ what's not to love?

I hope HabEx gets approved. Would be cool to have a giant sunflower in the sky.

Amazing video, as always, complete and clear. Great channel!

That sponsor eight sleep sounds amazing, I'm always too hot or too cold at night. Wishing you all a cool pillow tonight 😊

Astrum has quickly become one of my favorite channels! I love science!

Oh I can't believe I overlooked this video! I know it'll be interesting and properly informative. I'm glad this channel hasn't gone through the crazy changes like some other channels I USED to love watching.

I would be excited too if I got to try a 3.5k mattress cover. I'd love to know how it does in summer and does it have °C or just imperial units?

I wonder if I would still be alive when space tourism is as accessible as owning a car.

Good to know I'm not the only one who took one look at that last proposed satellite CG image, and thought "That one is called the 'Sunflower' for sure." I love the look of that one, and aside from Nautilus (which looks too demanding on energy reserves for their needed coordination precision without some sort of posable magnetic frame) I really would love to see these all approved, too.

i am intrigued by what a company selling heated mattress toppers can offer to a video about exoplanets? do you suspect these planets may use them?

At the point where I’m excited for new uploads - Probably watched the last 3 hour video 2 dozen times+ now (always dozing off, perfect sleep vid)

Really interesting topic and beautiful ilustrations Astrum, thank you Alex! Our life here on planet Earth probably originated somewhere else in space. Today we know that the fundamental building blocks of life arrived in the inner circle of the solar system about four billion years ago via comets and asteroids. Then they settled on Mars, Venus and Ceres - conditions on Earth weren't exactly the best due to the geological activity and toxic environment. Mars in particular was a paradise for emerging life and even today we can still find a few mysterious traces on the surface of our red neighboring planet... ​

Right in time for my bed time

Best space channel on youtube!

7:30 - 9:30 This puts Purple Rain into a whole new perspective O.o

There are so many variables..but also life is so adaptable. Look at Tardigrades. We just don't know enough. We can't even define where the parameters are for the possibility of life. Can Silicone lifeforms exist and what bio sign would such a thing create if any?

I’ve honestly wondered if life on planets is rare enough that we are hundreds of millions of years after the last sentient species or even just complex life evolved on a distant planet and hundreds of millions of years still until the next.

Curioius about the "industrial" complex-compounds supposedly found. Have they been verified and what are your thoughts. Thanks!

One (possibly critical) question that always bothers me, but I've never heard answered: "did the extremophile life forms we find on Earth evolve in those extreme environments - or did they evolve in a much more benign environment and then adapt to survive in more difficult situations?" The answer to this question has a massive impact on where we look for signs of life, because, if these life forms evolved in a benign environment and then mutated, it reduces the places we need to look greatly - to just one, rather narrow, range of possibles. Personally, I think the uniqueness of Earth (especially having such a large satellite) so unlikely to have occurred more than once, that, even given the almost infinite scale of the universe, it seems likely that life has probably only evolved a very few times, possibly only once. If you factor in the huge distances between us and the observable stars, with 'distance' = 'time', and reduce the visible universe down to the tiny part that is actually close enough to us to be considered 'real' (ie that it has a reasonable chance to still exist, and be roughly in the state that we observe), this seriously increases the likelihood of Earth's uniqueness, and therefore the chance of life evolving elsewhere, to practically zero.

I LOVE LEAN!!!!!!!! 💜💜💜💜💜💜💜💜💜

Prince would have loved this Purple Rain 🌂 🌧 💜 ☂️ ☔️ of Purple exo-Planets! 🎉 🎤 🎸

Whoa! I have 8 sleep pod. Highly recommend!!!!!!!!

We are lifeforms interested in finding other lifeforms on other planets, but at the present rate of environmental destruction soon there will not be any lifeforms on earth able to study if there are any other lifeforms on other planets in the universe. - Pierrot Armanno, writer.

Does anyone have any other science channels to recommend? I love this channel and would love to watch videos of a similar quality and validity. I've been trying to find some more but there are so many AI channels in the science genre. Thank you in advance

Purple Earth is a great band name...

"Because they are prettier! 🌎💜✨" Should be enough of a reason.

When you said "home" at 3:27, the hairs on the back of my neck stood on end. 😨 (👽?)

I wonder if some day we could see what is floating around distance planets. We humans have put a lot of space junk into space and it now orbits the Earth, that should reflect/block some star light, I would think? And we also need to find a way to clean up that space junk as well.....

should look into the Purple Dawn of creation theory

Purple happens to be my favorite color

_“How rare and beautiful it truly is that we exist.”_ _- Sleeping at Last (Saturn)_

Have you ever played the game, No Man's Sky. I would be interested in what you think of the Galaxy/Star/planet types that the game has.

Space pioneering is the future!

I think it's smart to use our planet as a way to find CARBON based life, where as finding any life would be kind of challenging since life could form in almost any planet with an atmosphere and a magnetic field.

Are there extremophiles on earth, that could survive venus? And if not, could we engineer them l?

I love how you say purple

One word of caution - extremophiles on earth have *adapted* to those conditions. It doesn’t follow that life could *arise* in those conditions.

Prince would be thrilled.

I have dreamed for years that someone would find life on another planet or celestial body, even if it is primitive, that would be enough to open up the whole universe.

Is “seeding” Mars with life viable in the far future?

MAKE LONGER VIDEOS!!!

Surely being many light years away from these planets you look for a planet with more primitive like atmosphere?

Are extremophiles really the things we should be studying as an example for what life could be like on exoplanets? I feel like extremophiles exist on earth because earth is otherwise an extremely welcome place for life. This allows for extremophiles to slowly encroach and evolve to fit their extreme environments. But for all the reasons that extreme environments are extreme, so are the reasons that those environments probably wouldn't give rise to life.

More than intersesting, thought provoking and informative, your videos are always beautiful in visual appeal as well !! Thank you for yet another great!! ❤

Shoutout David Talbot

In NMS we call those planets "Dissonant" 😏

Could you please make longer videos. It's just not enough time for me to fall asleep. I'm just watching the damn thing.

The universe has only given us humans one planet to survive on and when we destroy it that’s it! Yes I do believe and agree that there is other planets that exist for life but it’s not our planets it belongs to other life forms!

Wait, why did you show tardigrades when talking about extremophiles? I don’t think that they are…

❤

That sleep pod looks genuinely amazing but £2,095 is more than I take home in a month 🤣 I'm glad there's some rich folk out there getting some sweet sleep though. I'll just make do with my £50 mattress topper from Factory Outlet I guess 🤷

Gosh! Nothing can survive in a vacuum In the song "turn the page" From the band Rush was wrong....Ghhhhh...

Humans don’t even recognise other intelligent life on Earth, and what we’ve done to life we do recognise as intelligent……... We better hope and pray that we are alone in the universe because the BEST possible scenario is that we are found delicious enough to farm.

I must be an extremephile bcus i love me some heavymetal

THE WINE DARK SEA!

Considering how quickly life on Earth formed, how hardy said life was and how many worlds there are out there with conditions roughly in the range that the most resilient extremeness on Earth can handle, it would be REALLY strange for us to NOT find microbial life everywhere in the galaxy. Complex, or even intelligent life though might be a lot less common because of the series of events that need to occur and the amount of time with stable conditions required. Earth had simple microbial life pretty much since the frist solidified, but as far as we can tell multicellular life only came about around 600 million years ago (out of over 4 billion years), and intelligent life (humans) only came on the scene a few tens of thousands of years ago. We've only been blasting radio transmissions into space for about a hundred years. So if I had to put money on it, I'd say we have a good chance of finding microbial alien life within the next twenty years, maybe sooner. Finding technologically advanced life is probably going to take a loooot longer.

Because they have touristic value; I'd totally go live on one.

EXPOSE-R is kind of a funny name for an experiment apparatus. I hope the bacteria gave consent 😂

I clicked cos I was honestly curious what it is about yellow planets... did I just miss the part where the video answers the question in its own title

The planet Sha ka Re from Star trek😜

I wanted a like, but i don't know what to comment

Commenting for the algorithm…….

Hallo my fellow friends

My personal theory is that you have one life bearing planet per spiral galaxy. Everything from a supermassive black hole to sufficient phosphorus is required. There is a reason for our existence. We are not the result of random chance. Probability analysis of the necessary chemical reactions is shocking. One in 4.5 x 10^300 or once every 13 billion years chance of a ribosome occuring. To the 4100 power if you want a cell spontaneously forming. This assumes all amino acids, chemicals, and necessary conditions are evenly distributed throughout the universe. Theres no cheating and no getting around these facts.

"Look at how much more water Mars, Encelidus, Triton, etc, etc has than Earth." Poor Earth. Always getting water shamed. 😢

If we start finding purple worlds with basic forms of life, I think we should call them Noble Worlds. Borrowing a bit from our old symbolism of exepsive purple dyes.

Planets with unicorns ! Yes please ! ❤️

Would all water oceans be salty on other planets??

heartiest

I think this question is a bit more new ones than me. Think it is, but also there's a rational thing. Where thinking cause we don't know what? Came before the chicken to make the chicken. Hence the chicken and the egg problem which came first I don't think we're looking at the proper way we should love you looking at the accuracies have the chicken who made the first chicken?

What puzzles me is this. Earth life evolved to fit in with the conditions here on earth. Those conditions were not designed for us to live in, but evolved, and life was a part of that process. Why then do we continually look for life that is fundamentally like ours, in an ‘off earth’ environment that is totally alien to us. Shouldn’t we be thinking in terms of ‘off earth’ life having evolved to exist in off earth conditions. But we continually look for planets that have the ‘building blocks’ of life. Our life! Which can’t exist off earth. If aliens do exist, won’t they have evolved to fit in with the reality of space, and so be TOTALLY different from our earth form of life? So different that we wouldn’t recognise it as life even if we saw it?

I would like to know how the Earth had water oceans on it with no oxygen in the atmosphere, back then? As the water evaporates it would break down into its individual components, right? So, the atmosphere would have some oxygen in it?

We want something to be out there so bad we'll destory ourselves before we accept that we might just be an: accident.

I remember over 50 years ago the scientists used all say we need a planet with oxygen, water and a similar climate to Earth. Not anymore, I’m sure many scientists realise that life will exist in some very extraordinary environments.