Is Phobos Doomed?

What fate awaits Phobos, one of the moons of Mars?

Follow us on Twitter: @universetoday

Team:
Fraser Cain - @fcain
Jason Harmer - @jasoncharmer
Susie Murph - @susiemmurph
Brian Koberlein - @briankoberlein
Kevin Gill - @kevinmgill

Created by:
Fraser Cain and Jason Harmer

Edited by:
Chad Weber

Music:
Left Spine Down - “X-Ray”

“All these worlds are yours except Europa, attempt no landing there.”

As much as I love Arthur C. Clarke and his books, I've got to disagree with his judgement on which moons we should be avoiding.

Europa is awesome. It’s probably got a vast liquid ocean underneath its icy surface. There might even be life swimming down there, ready to be discovered.

Giant freaky Europa whales or some kind of alien sharknado.

Oh man, I just had the BEST idea for a movie.

So yea, Europa’s fine. The place we should really be avoiding is the Martian Moon Phobos.

Why? What’s wrong with Phobos? Have I become some kind of Phobo...phobe?

Is there any good reason to avoid this place?

Well first, its name tells us all we need to know.

Phobos is named for the Greek god of Horror, and I don’t mean like the usual gods of horror as in Clive Barker, John Carpenter or Wes Craven, I mean that Phobos is the actual personification of Fear… possibly with a freaky lion’s head.

And… there’s also the fact that Phobos is doomed.

Literally doomed. Living on borrowed time. Its days are numbered. It’s been poisoned and there’s no antidote. It’s got metal shards in its heart and the battery on it’s electro-magnet is starting to brown out.

More specifically, in a few million years, the asteroid-like rock is going to get torn apart by the Martian gravity and then get smashed onto the planet.

It all comes down to tidal forces.

Our Moon takes about 27 days to complete an orbit, and our planet takes around 24 hours to complete one rotation on its axis.

Our Moon is pulling unevenly on the Earth and slowing its rotation down.

To compensate, the Moon is slowly drifting away from us. We did a whole episode about this which we’ll link at the end of the episode.

On Mars, Phobos only takes 8 hours to complete an orbit around the planet. While the planet takes almost 25 hours to complete one rotation on its axis.

So Phobos travels three times around the planet for every Martian day.

And this is a problem.

It’s actually speeding up Mars’ rotation. And in exchange, it’s getting closer and closer to Mars with every orbit.

The current deadpool gives the best odds on Phobos taking 30 to 50 million years to finally crash into the planet.

The orbit will get lower and lower until it reaches a level known as the Roche Limit.

This is the point where the tidal forces between the near and far sides of the moon are so different that it gets torn apart.

Then Mars will have a bunch of teeny moons from the former Phobos.

And then good news! Those adorable moonlets will get further pulverized until Mars has a ring.

But then bad news… that ring will crash onto the planet in a cascade of destruction to be described as “the least fun balloon drop of all time”.

So, you probably wouldn't want to live on Mars then either.

Count yourself lucky. What were the chances that we would exist in the Solar System at a time that Phobos was a thing, and not a string of impacts on the surface of Mars.

Enjoy Phobos while you can, but remember that real estate there is temporary. Might I suggest somewhere in the alien sharknado infested waters of Europa instead?

What do you think. Did Arthur C Clarke have it wrong? Should we explore Europa?

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[billc.riemers]

Arthur C Clark had it correct.  In 2010 we were told to stay away from Europa, not because it wasn't interesting, but because that is where new life was still evolving.  Basically, we were prohibited from interfering with younger alien races, like a prime directive.   Europa is the most likely object in our solar system to also support a thriving eco-system, so he got that part right.

[tarogue]

The main reason to avoid Phobos is that it is the setting of the DOOM franchise.

[jcwilder]

one reason to not avoid it is to figure out what that "Monolith" thing is on it

[GirliqueMe]

And Deimos means terror, what a fun pair of moons they are 😊

[emlonewolf]

This was a great video.  Wonderful explanation... I never really understood why our moon and phobos wouldn't share the same fate until now, thanks.

[cigarboxguitar]

The reason the aliens in 2001 SO said we should not attempt to land their was to protect the life there. It was that life for which they created a mini sun out of Jupiter.

[BDBK]

I hope in millions of years, we will be at least a type 1 civilization, Mars will look more like Earth, and Phobos won't be an issue. We'll just put the little guy in a better orbit, or get rid of it.

[davidshafer]

I think we should land a rocket onto Phobos and push it into Mars orbit sooner so that it will impact as a bigger chunk. That way future inhabitants won't have to deal with deadly showers of meteorites.

[WayneMcCracken]

I think AC Clarke's prohibition for Europa was BECAUSE there is life (in the story), and that life is to be protected and allowed to develop undisturbed.

Phobos on the other hand must have devastating earthquakes due to the tidal forces. Likely a dangerous place to be.

Go to Europa !!! Hopefully they are friendly ;-)

[NorthernChev]

This is one of your best yet, Fraser. Hilarious. Great job!

[PrincessTS]

WE CAN JUST MOVE PHOBOS TO A HIGHER ORBIT USING A LOT OF POWER FROM EXTREMELY MASSIVE ROCKETS

[all]

Is it bad that I fucking cackled so loud I woke up my entire family at 2am when he said phobophobe

[undiecover]

Howabout before Phobos crashes we just launch its materials into orbit with a railgun and then use those materials to build some actually useful space stations

[demetricklouis]

I've seen The Europa Report. If life on Europa is anything like that, then Arther C. Clarke hit the nail on the head.

[IRONMANAustralia]

Phobophobe?  Meaning you fear fear itself?

No problem.  Set up your colony there, wait for Phobos to break up into more manageable pieces, then move those around or blow them up as necessary, let the smaller chunks hit the thicker newly terraformed atmosphere.  Fix'd.

[MilTacticsandStuff]

They should crash it into the surface just so we can watch.

[BlueUncia]

If we're still around by then, chances are we'll have terraformed Mars. Add an ocean into the equation, and what will happen to Phobos then?

[mattosnap]

I thought i was alone dreaming about alien whales under the icy shell of Europa

[cdanea]

Arthurc C. Clarke wants us to avoid Europa PRECISELY because it might sustain life. So, it sounds like even if intended as a pun, you used it in the wrong context. 
Other than that, you're great! Keep up the great work.

[grimcity]

It's kind've infuriating to know that we haven't explored Europa to a greater extent yet. 

I mean, I'm glad we're studying Mars, and I appreciate that we're getting some fantastic science from it, but bodies like Europa and Enceladus are significantly more dynamic and appear to be the most likely to harbor *current* life as we know it. 

It seems like if the US had maintained the political will that it had during the space race, we'd have already done the very things that now seem decades away from accomplishing. Hell, I'm almost 40 and the last manned visit to the moon was before I was born, and we aren't even equipped to do that right now.

Not taking away from all the good stuff we're doing, but it's frustrating to know that we could have already done so much more if we'd had the political incentive to spend the money and push NASA/JPL to get out and do more near-impossible missions.