@Background Pony #0F2C  
Lol, okay, let me clear up some misconceptions;
 
#1. This is kind of a forced-perspective shot. The hydrogen tanks are a good deal further away than it looks from here.
 
#2. The engineers have designed it so “everything is going to be fine”. For some perspective, the orange fuel tank of the Space Shuttle is holding some several hundred tons of “liquified hydrogen - flammable gas”, and it’s a lot closer to all the vibrations and heat than that tank is.
 
#3. This probably isn’t STS-51L - the infamous Challenger disintegration.
 
As for its cause, it was determined to be due to freezing weather the previous night stiffening one of the O-rings in one of the solid rocket boosters. So when the booster heated up and things expanded, instead of expanding and plugging any gaps like the O-ring is meant to, it either failed to expand or cracked, letting some of the SRB’s internal gasses out.
 
It’s very noteworthy that some engineers actually advised aborting the launch due to the cold temperatures of the previous night. Someone in the command line didn’t heed their warnings, though - at this point NASA had gotten very used to uneventful, successful launches, and had kind of forgotten what a dangerous business this is.
 
Anyways, the O-ring didn’t expand properly and fill the gap. As a result, combustion gasses could escape out the side. Giant fiery plume under rocket nozzle? Okay. Good. Supposed to work that way. Little jet of flame out the side of the booster? Very bad.
 

 
This caused heating in the orange external tank. The shuttle uses liquid hydrogen fuel - it boils at -423 °F, -253°C, so it boiled and overpressurized the tank, causing it to rupture.
 
(As a result of this, the pressure readings on the MPS display must’ve gone wildly off just a second or so before the break-up. So the astronauts actually saw a problem come up just a second or so before it happened.)
 
From there, everything happened in less than a second. This was at a point in the flight when aerodynamic stresses were enormous. Compromised, the structure of the tank could no longer take it and it broke up. This caused the shuttle to pitch violently and impact the oncoming air - during this time of enormous aerodynamic stresses - at an angle it wasn’t meant to, causing it to break up.
 
The boosters actually kept on going, leading to the characteristic two fingers off the explosion cloud.
 

 
Seen from another angle:  

 
It’s kind of creepy and surreal how their internal guidance systems (I think?) kept them going on the launch trajectory, obliviously unaware of the fact that the craft they were boosting had completely broken up and was no longer attached. Notice how their paths turn - that means the explosions and such kicked them off-course, but their guidance systems corrected it and re-pointed them in the right direction.
 
The Solid Rocket Boosters (SRB’s) carry “range safety” explosives meant for this exact kind of event - they could actually reach a number of cities in the area if they went the wrong direction, so the range safety devices were activated and the boosters destroyed. Though they weren’t going in a dangerous direction (launches are East, over the ocean for this reason), they would’ve just launched up, re-entered too steep or too fast and been destroyed on re-entry later, anyways, so this was safer - and this way they wouldn’t have to worry about them while they tried to sort out what was going on with the orbiter - the “plane” part of the space shuttle.

so thats why the Challenger exploded….

@Tk3997  
Wow, you’re a duck.

I like this image macro trend, I would like to see more as well.

Lol. Kranz is rolling in his grave.

Ooooh nooooo. Don’t do that OP. Otherwise, Twlight won’t post on the site.

I’m a bad person, but I cannot stop laughing.

@Tk3997  
We should switch this meme from disasters to movie posters of things like Star Wars The Phantom Menace and The Last Airbender.

@Tk3997  
You should do it anyways.  
I shall send you a virtual cookie if you do.

@WatermelonRat  
It’s about time, the older the tragedy, the easier it is to make light of it. Challenger can still be a sore spot for some even if it happened nearly thirty years ago and I don’t even want to touch the Halocaust

@WatermelonRat  
LOGIC!
 
Also I’m really tempted now to make one of like an Iraqi invasion map just to see how much rage it causes… still I’m not quite THAT big of a troll.

@Lard Of Dorkness  
A thousand people on the Titanic is fine but seven astronauts are too much?

Gonna show age, saw that explosion.

Pff it was decades ago and killed less then ten people, let’s have some perspective here guys. Compared to other crap we joke about this is nothing.

@Background Pony  
Why the heck are you providing him ideas?

This kind of stuff is gonna get old pretty fast.

I think you are crossing a certain line here.

I know, let’s make one about the HOLOCAUST!

What next? Wtc?

Wow dude. Just…wow.