Ridiculous Lava - Is this a glitch?

Hi!
I was mining on a forest world and went quite deep. I then hit this ridiculous perfectly level magma chamber. Is this a glitch? I dug sideways as well and it went on forever. I have a suspicion that I might have hit the core of the planet. Is this possible/true?

 

Yes, that is the limit...did you see any dinosaur's?

 

Actually, you can go deeper by making a tunnel downwards.

 

That's the core, and if you use blocks to cheese yourself even further down you'll die instantly.

 

God dammit lava. Stop being ridiculous :/

Yeah, you've hit the core. If you place 3 x 3 blocks and then mine through it you can keep going though

 

Actually, it's not the core. It's the start of the mantle. Going any deeper would crush even the thickest impervium armor.

 

So I did the impossible? Crazy stuff.

 

Strictly speaking, the bulk of the mantle is still largely solid. It likely has a consistency similar to hot asphalt; slightly plastic and bendable, but still a solid by any meaningful definition; though it'd be extremely hot too of course. The only "completely" liquid part of the Earths interior is the outer core, the inner core is probably a solid; if not a single gigantic crystal

Let's just say it's best not to go to Starbound for accurate geophysics