Wanna get dirty with me?
From star stuff to microscopic fluff to skin cells that slough while you’re in the buff, the universe of dust is curious enough to turn your mind into a cream puff.
May this week’s episode spread like dust on the wind.
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Our Atmosphere is Escaping!
Oh gahd! Quick! Take a deep breath!! Someone save Minute Earth!!!
What’s that? Oh … we have nothing to worry about? It’s only losing hydrogen and helium? And it will take billions of years to lose that stuff? Whew.
Bonus: Check out my YouTube vid about just how small (and shared) our atmosphere really is.
Time for a science-tastic, carboniferous Episode Extra™ to accompany my latest YouTube vid!
In the most recent episode of It’s Okay To Be Smart on YouTube, about how we all share the same air, the #1 question from People Who Are Watching was about a number I mentioned in the beginning: We hoomanz are emitting 33-34 billion tons of CO2 a year. If the atmosphere is so dang big, is that amount of CO2 a lot?
A few people were subsequently all “Wait a sec, is Joe referencing climate change here?! Rabble rabble rabble!!!" Congrats. You caught me. Guilty as charged. But there’s science on my side, and you know what they say about science:
Where the carbon comes from: the primary people-caused CO2 sources are fossil fuels, deforestation, and cement production. Since 1850, over one thousand billion (AKA “a trillion”) tons of CO2 have been added to the atmosphere. We put about 34 billion tons of CO2 into atmosphere in 2011, the latest year I could find data. These are not debatable facts, minus a few decimals of statistical error. We can measure them, we have the technology.
Where does it go? Only 55% of this is removed by the oceans (dissolved CO2 and photosynthetic organisms) and the plants in our jungles and forests. Fifty years ago, as much as 60% of that CO2 would have been removed by oceans and plants. That means that not only are we increasing the amount of CO2 we emit every year, but plants and oceans (the carbon “sinks”) can’t keep up with the rate that we are adding it to the atmosphere.
Sure, as more carbon is put into atmosphere, plants and plankton can reproduce and take more of it up. But if we pump it out faster than they proliferate, it’s still a net loss. Oceans might actually be less able to absorb CO2 as the world warms (it’s simple chemistry, think about warm carbonated soda).
Then we get to the warming part. CO2 makes up less than one tenth of one percent of Earth’s atmosphere. So it can’t be that big of a deal to increase that by like 0.01% right? Wrong. Sure, for every million molecules of air, only ~391 of them will be CO2, but carbon dioxide is an amazingly powerful molecular mirror for solar energy, reflecting it back down to Earth and heating our planet. The math is complex, but tenths of tenths of percent changes in CO2 concentrations can lead to full degree changes in global temperatures. This doesn’t even include the effects of methane, which is almost 1,000 times less abundant as CO2, but contributes a whopping 1/5th of greenhouse gas effects.
For more: A paper in PNAS about carbon emissions and carbon sinks. A summary of emissions, warming and greenhouse gases from NOAA. Finally, you might need this: How to talk to a climate skeptic.
Your long wait is over … the new episode of It’s Okay To Be Smart is up! Whose air do we share?
I had a random thought while out jogging recently: With all of the deep breaths I take every day, how much of Earth’s atmosphere do I breathe in and out during a lifetime? Could I be sharing air molecules with Albert Einstein or Charles Darwin or Cleopatra?
And how big IS the atmosphere to begin with? I decided to calculate how many air molecules we might all share. It really makes you think about what we’re putting in the atmosphere, eh?
Thanks for watching, and stay curious! Share with your friends, click here to subscribe, and check out the rest of my science videos on YouTube!
A Quadruple Lunar Halo Over Spain (and How!)
Moonlight is beautiful all on its own, but every once in a while the interactions between our atmosphere and lunar light really take it to the next level. You know I rarely give you a beautiful picture without trying to tell you something sciencey about it :)
Inside of this beautiful photo by Dani Caxete, we can see four unique atmospheric “halos”. Microscopic ice crystals in our atmosphere take on certain shapes as they freeze, and those shapes refract light at very particular angles, like icy prisms.
We get 22˚ and 46˚ halos (because of the shape of the ice crystals and the special angles at which they refract light), and two arcs growing off of those halos. It’s all the result of moonlight bending through falling ice crystals, randomly oriented throughout the night sky, a few of them beaming light toward the camera. Here’s an annotated version of the above photo, with all the halos labeled:
Want to learn more about these amazing refractory effects that we often see around the sun and moon? Check out my earlier post about a beautiful set of halos in Greenland, and Atmospheric Optics has the definitive encyclopedia of halo phenomena.
Aerosols, clouds of microscopic particles suspended in air, are key players in the health of our atmosphere and climate. They also happen to make really pretty sunsets. Aerosols can scatter sunlight back into space, which can cool the planet, or seed dangerous chemical reactions like those that destroy ozone. Understanding how different types of aerosols move and react in our atmosphere is crucial to smart climate science.
The image above is a NASA supercomputer simulation of different aerosols moving around Earth. It sort of looks like someone painted Earth and then swirled the colors around before they dried, doesn’t it?
Dust is red (remember that half the Amazon gets its nutrients from African aerosols!), smoke from fires is green, volcanic eruptions are white, and sea salt is blue.
See the beautiful hi-res version of the image here. Phil Plait has more explanation at Bad Astronomy (now at Slate!)
If you loved this visualization, revisit NASA’s Van Gogh-esque Perpetual Ocean current simulation. Beautiful stuff.
Capturing a Heavenly Halo at Greenland’s Summit Station
It’s easy to see a photo like this, pause for a moment, let out an “ooh” or an “ahh” or two, then continue on about your business. But that takes all the fun out of it!
Let’s stop for a moment, and really appreciate what’s going on in this picture. What is the science behind such atmospheric phenomena?
- Almost every optical phenomenon in the daylight sky, whether it’s a rainbow or a halo or a “sun dog”, occurs due to light bending through water that’s suspended in the atmosphere. That water could be liquid (like rainbows) or crystallized ice (like above), but it acts as a prism all the same.
- Start with the inner ring around the Sun. This is a solar halo. To be precise, it’s probably a 22˚ halo. This ring occurs when hexagonal ice crystals, randomly distributed and aligned in the atmosphere, refract light coming from the Sun back to the eye of the viewer. While every crystal of ice in the air is bending the light that hits it, only the hexagon-shaped crystals that happen to be sitting at exactly 22˚ away from the Sun AND oriented just right are able to bend light straight back at your eye. This is because of their particular six-sided geometry. Someone standing 50 feet to your right would see the same halo, but from a completely different set of randomly aligned ice crystals!
- What about those two orbs of concentrated light to the left and right of the Sun? Those are called "sun dogs". Aristotle used to refer to them as “mock suns”, chasing the real Sun through the sky. They usually are only seen when the Sun is low in the sky, and always at the same elevation as the Sun itself. What causes these? The same ice crystals as the 22˚ halo! You see, as the hexagonal crystals sink down to Earth, they begin to align. It’s the same thing that happens to a falling dart: the air resistance makes them stand up straight. Remember how the 22˚ halo was formed by whatever crystals just happened to be pointing our way? The sun dogs appear brighter because there’s simply more “ice prisms” pointing in the right direction to send light into your eyes. You can even see a red-to-blue prism effect at work, since different wavelengths of light get bent at slightly different angles.
- And that blob at the top of the halo? That’s an upper tangent arc. It’s origin lies in the same alignment of ice crystals that form the sun dogs, but instead of falling vertically, they are arranged horizontally. If you look closely ou can even see the far edges arcing down like wings, suspending the orb of light in mid-air. The arm of light reaching upwards like a solar pillar is the result of simple reflected sunlight off of the icy faces of suspended crystals.
- The outer ring is perhaps the most rare. I’m pretty sure that’s a 46˚ halo. The same hexagonal ice crystals are at play, but instead of bending light through their six-sided faces, they are bending it through their base. That particular geometry of refraction gives bends light at a wider angle, meaning the halo is larger. It’s fainter, because there are fewer ice crystals randomly oriented that way, and can only be seen when the Sun is low and the air is clouded with frozen water.
There’s definitely more in there that I’m not mentioning, but wow … right? Sights such as these would be carry plenty of beauty without further explanation, but a little knowledge certainly enriches nature’s grandeur, no?
(via Alan Boyle, photo by Ed Stockard)
You may have heard about radioactive sulfur being analyzed in California recently, sulfur that had migrated across the Pacific. What does that have to do with coal?
Well, what we learn from the sulfur that migrated over the Pacific might help us understand what to expect from China’s expansion of dirty coal plants and how they might affect the global climate. Maggie Koerth-Baker has more at the link.
(via Boing Boing)
Source: Boing Boing
We live on an amazing planet, and it is quite different at its outer edge than it is from its inner reaches.
When you click-through that picture up there (and trust me, you want to click through) you will be treated to a nice tour of the many layers of our planet, top to bottom. You will also want to thank me for not actually posting that picture on your dashboard.