What is the Triangle Light on the Altimeter For?

[SteveD80]

The altimeter at the top of the screen has lots of buttons and information on it.  The abort button, an atmospheric pressure gauge a vertical speedometer, the lights button, the gear button, the brakes button, the crashing indicator and a little light up triangle that sits at the top between the altitude and vertical speed gauge.  What is the mystery triangle for?

[Leeman]

if the triangle is lit green, you are safe to recover the vehicle and go back to the space center.. if the triangle is blue you can only go back to the space center

[Reactordrone]

It has different colours in different situations. Green when you're landed on kerbin, unlit when you're in flight in an atmosphere, blue when you're in space and orange when you're accelerating in space.

[N_Molson]

I always considered it as some equivalent of the "Contact Light" they had on the LM.

[bewing]

Or orange when you are landed on another celestial body. It's fun for Kerbonauts running across the Mun ... blue/orange/blue/orange -- every time they take a step and leap into the "air" again.