Hi all. It’s been a while I’m ashamed to admit. I’ve been working on a new Facebook group to raise the profile of my channel. It’s been fun. Here is the link (hint: join the group!)
Here is my newest video. A basic breakdown of what exactly the Goldilocks (or circumstellar habitable) zone is, and it’s importance to life on Earth. If you like the channel please subscribe!
I’ve also provided the script/transcript for my upcoming episode of “Astro-Biological:”, which introduces us to the concept of the Goldilocks Zone….
G’day! Welcome to Astro-biological:!
Ben what the heck are you talking about? What’s the connection?
Let’s go check out THE GOLDILOCKS ZONE!!!!
Life, as I like to remind you, is really special. Here on earth, life exists only because certain conditions are met. Today, we’ll consider water. Everything needs it, but it only exists as a liquid at the surface here on Earth.
So? Big deal right?
Well it is actually!
Check out the sun. Giver of life! Driver of climate! Pumping out some pretty respectable energy. How much?
1 yottawatt equals 10 with 26 zeroes after it!
Brutal! And the sun is a pretty average star! Nothing special about it!So there’s plenty of sunlight for everyone!
Could other planets benefit from the sun’s golden goodness the way we do? Let’s take a look at the inner planets. They’re the only ones that really matter in all this…
Let’s see…Mercury, Venus, Earth and Mars. The rocky planets. The so called “Terrestrial Planets”.
Mercury is 58 million kilometres from the sun. That’s really close. This close proximity has turned Mercury’s surface into an oven, where liquid water couldn’t possibly last.
Let’s visit the next in line: Venus. Venus is similar to Earth in composition, gravity and size. Long ago Venus might have had oceans just like Earth, but again the planets closeness to the sun and other factors saw all that water disappear into space. Venus is now the hottest place in the solar system. Definitely no liquid water there anymore!
Wanna know more about what happened to Earth’s twin? This guy I know made a video!
Earth! Beautiful Earth. Our home. Every thing’s home actually. Eighty per cent of earth’s surface is covered by liquid water. There’s so much spare water here that our bodies are mostly made up of it! It’s absolutely everywhere, even locked up deep in the earth’s crust! Enough of earth. We’ve all been there.
Next planet out:
Mars. The cool planet. Every one wants to go here. Pity it’s so cold! Liquid water may exist here in tiny amounts, but most of the red planet’s water is locked up as ice or permafrost just below it’s surface. Plenty there for future colonists to use, but nothing readily available for biological processes. Pity. It’s a beautiful planet. Just ask Matt Damon!
So what is the Goldilocks Zone then?
Here’s the inner solar system. Mercury, Venus, Earth and Mars. Let’s visit a special guest who can explain the Goldilocks Zone for us…
ChefBenbit. (Watch the video when it’s up!)
Nice work Chef! So, if Earth was a bowl of porridge it would be the one Goldilocks ate: the one that was just right! it’s that simple! Earth is lucky enough to be at the perfect distance from the sun, where water likes to slosh around in liquid form. Things would be a lot different here if that wasn’t the case.
So that’s it for now! A simple but important piece of information. The Goldilocks Zone!
How am I going so far?
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Thanks for watching astrobiological. Giving you the universe in plain human. Ciao!
So. We exist here on our rock, as it flies around our medium size main sequence star, and slowly but surely begin to realise that we are not quite as special as we think. Sure, we’ve come a long way. This isn’t necessarily a good thing. Progress is literally a moving forward. By this rationale the human race has made astonishing progress in the last two hundred years. I won’t rattle off the myriad achievements we’ve ticked off the sentient species bucket list, but we’ve done a lot- let’s just leave it at that. The mobile device or computer you’re reading this post on is one tiny part of that progress.
But one piece of wisdom we have gained in the midst of all this gadgetry is this:
We are not the centre of the Universe.
There. I said it.
Ever since Copernicus, Gallileo et al realised that Earth revolves around the Sun, much human progress and thinking has revolved around the fact that no, we are not the focal point of creation, life has gone on before us (and will carry on long after we’re gone), and that our very planet is turning out to be not quite as unique as we thought.
It seems like every second week a new exoplanet is being discovered and added to a growing bestiary of worlds. Most of those worlds are nothing like earth: but I believe it’s only a matter of time. In our own solar system water; that miracle ingredient for the appearance of life is turning up everywhere we look.
Water is a bit of a superstar. I won’t espouse it’s virtues here, but suffice to say, absolutely no life (as we know it) can exist without it. Water is turning up everywhere it seems. Here are a few examples. I will begin this tour with with the inner planets of the Solar System. For the sake of brevity I will only glance on each location. At this point in time current thinking is focused on certain moons in the outer solar system: “outer” meaning beyond the asteroid belt. Water appears to be abundant as we head outward, but I think it fair that the terrestrial planets get some love too. After all, should humanity ever sort out its myriad problems and eventually stops just dipping it’s toes in the water, one of these worlds might just be a new home for our species. The presence of water would be highly advantageous.
Let’s put together a little list of locales in the Inner solar system where water is thought to exist. I will include Earth here as the first obvious example.
Home to over 7 billion talking monkeys, loads of beetles, bacteria and a whole pile of other beasties all jostling about on the Tree of Life. A middle aged planet, third from it’s parent sun in a non-descript solar system moving quietly through the Orion Arm of the Milky Way Galaxy. There’s a lot of water here, about 1,260.000,000,000,000,000,000 litres. That’s 1260 million trillion litres.
Now, obviously that sounds like a lot, but if you want to really get an idea of how much water this is, just ponder this. Of all water on earth, 96% is saline. Four percent exists as freshwater. Of this four percent, sixty eight percent is locked up in ice and glaciers. Thirty percent of the remaining freshwater is groundwater, and thus not accessible to all and sundry.
About 0.006 of this four percent exists in rivers and lakes.
This tiny sliver of the total global water pie keeps all of us talking monkeys alive.
So, where is this going?
There are vast amounts of water on Earth. But Earth is only one of 8 other planets in the solar system. There are also five dwarf planets, of which Ceres and Pluto are the most famous examples, and 182 moons orbiting various objects and bodies throughout the solar system.
Say again?, you ask. “Ben, are you out of your gourd? Isn’t the Sun that great big hot thing at the centre of the solar system? You know, that really hot thing that is so hot we can feel it’s heat here, from 93 million kilometres away?”
Yes, Dear Reader, the sun is that big hot thing. But researchers have demonstrated the existence of water vapour in the central cooler regions of sunspots. Apparently, so the science goes, these regions are just cool enough that hydrogen and oxygen can get all chummy and form water. Now, liquid water (and obviously ice) are out of the question, but there you go. There is water on the sun. Next.
Poor old Mercury has never had a good trot. The closest planet to the sun, Mercury got baked clean millennia ago. No atmosphere worth mentioning exists, and so you’d think that’d be it. It’s just a barren hellish wasteland. Right?
Like all of the inner planets, Mercury has taken a thrashing from impacts over it’s sad history. It skims around the sun pocked with craters. Some of these happen to sit right on the Mercurian Terminator. A terminator is not a killer robot with poor acting skills. A terminator is simply the demarcation where the planet’s daytime side meets the night time side.
This means that some of these craters contain regions draped permanently in shadow. Similar craters exist on our very own Moon, and yes, water ice has been observed in them! These ice filled craters are being touted as a bit of a sweetener for permanent human habitation on ol’ Luna.
Alas, Mercury doesn’t have much else going for it. It completely lacks a magnetic field, and lost whatever atmosphere it ever had long before Eukaryotes began crawling around.
Say you were an alien visitor to our solar system. Imagine yourself flying in: past the gas giants (what’s with that big red spot?), past all those pesky asteroids (that weird metal asteroid warrants a second look!), even past that blue green marble, with all the chatter pouring out on the electromagnetic spectrum. You keep on flying. It’s been a long flight, but there are two more planets to look at. This next one looks liks a big deal!
As you approach Sol 2 you’re thinking this place seems like Sol 3. Gravity is pretty similar , and it’s about the same size. There are even clouds here: lots of them!
Oh. It’s time to stop using your eyes and switch on some of that fantastic alien technology of yours.
Sol 2 isn’t so nice after all. In fact it’s downright awful. Some sort of disaster has befallen this planet. No magnetic field, atmospheric pressure that will crush your delicate little space gazelle should you ever choose to land and temperatures that can bake cakes.
There is water here though! Thick choking clouds of carbon dioxide and sulfur enshroud the planet, but there are traces of water in the atmosphere! It’s only 0.002 percent to be sure, but it’s there.
Your space gazelle (translation: extremely sleek and advanced spaceship) has beauty AND brains. Scans show hydrogen and oxygen ions trailing out behind the planet, and you realise that water loss is an ongoing issue for Sol 2. Solar winds have been slowly stripping Sol 2 of water for a long time; maybe billions of years, leaving this hellish dessicated planet behind. It’s a pity, you figure. Sol 2 would have been nice once. Sol 3 beckons as a potential home sometime, but the natives are barking mad. Looks like rolling in and blowing stuff up might be the only way after all. All that water!
Sol 3 has been studied to death, so you decide to swing around and take a look at the Red Planet.
Dry as a bone. Peaceful to be sure, but this planet is dead. Weighing in at roughly one third the size of Earth, Sol 4 may have struggled to hold onto any atmosphere it may have had.
Of course, being a little guy isn’t the be all and end all. Titan is the largest moon of Saturn. Somewhat smaller than Mars, yet fifty percent larger than our own moon, Titan sports an impressively thick atmosphere: thicker in fact than our own. Unfortunately Titan can be shunned from this article: it posesses oceans…..of liquid methane. No water here folks. I include Titan to demonstrate that smaller worlds can possess respectable atmospheres.
Mars, like Venus, is missing a key component here. Earth is the proverbial bowl of perfect porridge; just right. Many features of Earth are conducive to life, but perhaps one of the most important is the presence of an active core. This one feature prevents harmful cosmic rays from degrading DNA so badly that life mutates itself to death. It also prevents said rays from stripping away our water and atmosphere. This appears to have happened on Mars and it’s happening on Venus as we speak.
Does it, doesn’t it?
Mars is turning out to be a slippery customer. Evidence for erstwhile liquid water on the red planet seems to be piling up. It’s heading toward consensus that Mars once was much warmer and wetter than it is today.
NASA’s Curiosity rover is the closest we’ll get to visiting Mars for some time yet, and it has captured some pure Martian magic on it’s sojourns across the dead and lifeless face of possibly humanity’s first true stepping stone to the stars.
Possibly the greatest aspect of Curiosity is that it is a quintessentially human mission. Human eyes see the surface of Mars, beamed across vast distances and tease out information about this place. One simple photo can convey a lot if you know where to look and what to look for:
Essentially the general thrust of new discoveries these days is that it’s more likely for water to be somewhere than unlikely. I will end this blog post with new insights into water back here on Earth. As mentioned previously, several moons in the outer solar system are posited to possess vast quantities of water in the form of sub surface briny oceans.
However, it turns out Earth has a few surprises still up it’s sleeve. A diamond ejected around 90 million years ago from a volcano in Juina, Brazil contains imperfections, that, like a seemingly trivial clue in some glossy crime investigation show, point the way to to the one time existence of a subsurface ocean deep in earth’s crust. In fact, this ocean was (is?) posited to have descended nearly a third of the way to the edge of Earth’s core. These clues come in the form of hydroxyl ions, which normally only come from water. More evidence is arising, pointing toward water’s earlier appearance on Earth than expected. I will write about this and similar topics as I am able.
More posts on water in the solar system will be up as soon as I find time to write more. Keep on looking up! The Universe is there. See you next time, and thanks for reading.