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If we’re going to send people to Mars someday, we’re going to need to be very conscious of the challenges presented in this endeavor. And at the top of that list is the ferocious nature of dust on the barren planet.

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[♪ INTRO] If we're going to send people to Mars one day, there are a lot of challenges we need to prepare for.   The planet is cold, barren, and  suffocating... the list goes on.   But one challenge that might not be at  the top of everyone's list is dust.   The Red Planet is basically one big desert  with wind whipping up dust all the time.   Some storms grow so large that  dust fills the entire atmosphere,   plunging the planet into darkness.

But a bunch of kicked up Martian   dust does more than turn day into night. It also causes planet-wide temperature swings.   And if we're gonna to spend some time there,

we’d better learn more about how that works.   One of the first spacecraft to  investigate how Mars’s dust   affects the planet's temperature  was an Indian spacecraft   called the Mars Orbiter  Mission…also known as MOM.   MOM entered Mars’s orbit back in September  of 2014, and it was outfitted with   five instruments designed to study  the planet’s atmosphere and surface.   Lucky for MOM, it didn’t have to  wait long to start science-ing.   The very next month, it spotted  a small-scale dust storm   forming in a northern region  known as Lunae Planum.   Scientists watched the storm  grow over the course of a week,   move southward toward the equator,

and then disappear a week later,   leaving behind a haze of floating dust.

Due to the lack of rain, lower gravity,   and a much thinner atmosphere,

Mars’s dust can hang in the air   for way longer than Earth’s usually does. The team tracked this dust and its effects   over a whole year

and then published   their findings in a 2018 paper. The MOM data showed that once dust   drifted over the equator,

rising air swept it up into   the higher layers of the atmosphere.

Ultimately, the dust reached altitudes of   up to 20 kilometers above the surface,

and despite all these particles partly   blocking the Sun, the atmosphere

in this region got warmer…as much as   10 degrees Celsius warmer. Not only that,   but temperatures rose significantly

faster than they did before the storm, too.   As odd as that might sound, scientists  weren’t entirely surprised.   Because any time a bunch of dust gets  thrown up in the air, it can mess with a   planet’s climate in one of two ways: It  can cool things down or warm things up.   Which way things go all comes down to

the properties of the dust and how   it interacts with sunlight. Basically, whenever you have tiny   particles floating in the air, known as aerosols,

they will both absorb and reflect different   amounts of the Sun’s light.

The light that reflects off of them   generally just bounces back into space. Since it never reaches the surface,   that causes a drop in temperature. But not all sunlight gets bounced away.   Some gets absorbed, and eventually  re-radiated by whatever particles   did the absorbing…either into the atmosphere or

towards the ground, heating things up.   In fact, this part is a lot like  how greenhouse gases work.   A lot of times, Martian dust reflects  light right back into space,   which causes a cooling effect.

But when the particles are big   enough or dark enough in color, they can absorb

a decent amount of sunlight and then re-radiate   it, causing a warming effect. Dust also interferes   with the radiation leaving Mars. Since Mars’s atmosphere is so thin,   it doesn’t act much like a blanket,

trapping heat the way Earth’s does.   Normally, its heat really easily  radiates back out into space,   but when there’s a bunch of dust in the  air, it can act more like a blanket.   Other factors play a role too,  like the altitude of the dust   and its location on the  night or day side of Mars.   In the end, the overall warming or cooling effect

depends on how all these factors stack up.   Now we don’t know exactly which factors  caused the warming that MOM observed.   But its results illustrate how  complex this phenomenon can be,   and how drastically dust  can affect Mars’s climate.   Now, this isn’t a completely  unfamiliar phenomenon.   We get aerosol cooling and  heating on Earth, too.   Ash from a single volcano can make  temperatures drop around the world.   And dust over the Sahara can heat  up the air over the desert.   But the dust storms that tinker  with our climate don’t have   effects on the same scale as those on Mars.

Earth doesn’t get the planet-wide   dust clouds that

blanket the atmosphere   for weeks or months at a time. And on Mars, there’s a kind   of positive feedback loop. As the dust stays in the atmosphere,   heating up the air,

that can build up   the temperature difference between

the different regions of the planet   and between the ground and the air.

That difference then causes more wind   that stirs up more dust,

and the cycle continues.   Eventually, enough sunlight gets blocked that

the temperatures do start dropping,   which brings the storm to an end. But the dust can still spend   enough time in the air

to affect the climate for   an extended period of time. What’s fascinating about   all this is that Mars has been

barren and dry for billions of years.   It doesn’t have a water cycle or thick  atmosphere to drive dynamic changes.   Instead, its dust rides the  drafts, moves energy around,   and creates new winds that are constantly  reshaping the planet’s surface.   So this dust can tell us a lot about  how Mars’s surface and atmosphere   evolve together… and how these tiny  particles shape the whole planet’s climate.   Thanks for watching this SciShow Space video!

It marks the end of our year   exploring the solar system

with the final pin of 2022, featuring MOM.   For the entire month of December, you  can find a MOM pin at the link in   the description down below or even  bundle it with the SciShow pinboard.   In the new year, we will offer a different  pin starting off a whole new theme.   I’m not gonna tell you what it  is, but if you buy the MOM pin,   I’m sure you will rock it. It’s available for order online where you get   all the pins of the month: at [♪ OUTRO]