Can white castle?

Some of you may have seen this before so you will know the answer but for people who haven't, can white castle?

White can castle kingside or queenside in that position, providing the king and the rook he wants to castle with haven't previously moved.

What am I missing?  Why couldn't he castle?

If there was a white pawn on d2, he certainly wouldn't want to castle long... it would be a mate in 1 if he did.

And yes, the position is possible.  White can castle long or short.

1. d4 d5 2. Qd3 Qd6 3. Qf5 Bxf5 4. a4 a5 5. Nc3 g5 6. g4 Bxg4 7. Nf3 Bxf3
8. Bf4 Nc6 9. Bxd6 Bh6 10. Bg3 g4 11. Bh3 Bg5 12. Bf4 Bh6 13. Bxh6 Nxh6 14. Bxg4 Nxg4 15. Nxd5 Ra6 16. Nf6+ Kd8 17. Nxg4 Rb6 18. Ne5 Rb4 19. Nxf3 Rxa4 20. Ne5 Rxd4 21. Nxc6+ Ke8 22. Nb8 Rd8 23. Nc6 Ra8 24. Nxa5 Rb8 25. Nc4 Ra8 26. Nb6 Rb8 27. Na8 Rxa8

If you think white can castle what was his last move?

It's listed in the pgn I provided.  I gave the entire game.  Na8 was White's last move.  Then Black captured the knight on a8.

he just needs to have had black have taken a piece of his for his last move, mr ed there kindly posted a sequence of moves that ends just so.

Can't see wgy he would want to. Better to just take the rook. :)

as long as r. has not moved.....white can castle either way.

make that both rooks :P

True.

Yes, you can tell by examining the FEN string - it clearly shows castling possible for both sides which means the king & rooks havn't previously moved and there's no legal reason why not. 

White can't castle on queenside because the rook at a8 is attacking the one at a1. Castling on kingside is possible if the King doesn't move yet. :)

1.Rxa8+ skewered the King and rook. 

Not true - the fact that the rook is under attack doesn't matter. Castling is illegal if the king is in check or moves through an attacked square.

You can always look here:-

http://www.chess.com/learn-how-to-play-chess.html

Yeah because castling is always superior to winning 2 rooks.

Theoretically, white can castle either side.

Practically, even the worst patzer on earth would play 1.Rxa8+...

However if white can castle on either side, black cannot, and vice versa.

Only if black's rooks where moved would casling be illegal (Or if he moved his king or either rook before) 

You need to brush up on the rules of chess!  The fact the Black is attacking the rook at a1 is irrelevant.

Why does white want to castle if there is a free rook smart!