huge difference between blitz and rapid rating

While I agree with much of what toastypostion said I will like to point out a misconception on the ease of climbing as a new player. While you can get an easy 200 points for winning the first game the rate at which you win points will decrease and keep in mind that should you lose the same amount points will be lost. Look at those GMs who chose to create a new account and climb to high ratings without ever losing it still takes a lot of games to go higher

^^^^That argument doesn't hold water. Ratings here are calculated based on several hundred thousand active players. Unless a strong player has literally hundreds of accounts they won't be taking enough points out of the ratings pool to have a significant effect on the whole pool.

PS You don't look like you're any better at this game than I am. Why worry about the difference between being in the 80th percentile vs the 85th?

The basic reason could be that You are better at Calculation than Instinct. In longer time control games you have time to calculate deeply but in blitz you have to rely on instinct after sometime. You would like to do more tactics and study positional concepts many times, to many positions into your pattern recognition mechanism for quicker decision making.

Very well explained #2

That's why you start at 1200 on this site and your rating moves around with smaller swings as you play more games and the system has more knowledge of the strength at which you are playing.

I would assume so. And so what? Unless they sandbag it takes 10 or so games to find their bracket. If the 1200 player is known by the system s/he would lose 8 pts when they lose. The unknown new player would gain 100+ pts if that was their first game as the system tries to set their rating accurately.

If you understand Uni level math, look up the Glicko rating system for chess (or any game)

That's not how the system works unless both players are new. If one player has an established rating but the other one is playing their first game, the ratings change is big for the virgin, but the established player only has a change in line with what change would have occurred against a known opponent.

You can test it. Set up a new account and play a game against someone with plenty of games played. Look at how the ratings change for both accounts afterwards.

I often see one speed improving while another gets work. I think it is best to play a mix of time controls. But obviously longer=better for improvement purposes

Blitz is a lot of memorizing of all openings. If you are not very familiar with all the openings, you will end up losing in blitz. 

Same thing happens to me. I'm over 1900 in rapid but can't seem to get past 1600 in blitz. Although I think it's more down to me making massive blunders I wouldn't otherwise make when I have more time to think. 

yeah its really strange, I  can easily get around 2000 on rapid, but I've been trying really hard to get higher on blitz but my highest is like 1850. Its hard not to make blunders and also not get into time trouble, but the players in blitz are definitely a lot stronger. 

I think for the same rating, player in blitz is simply stronger.  In general, I think the player pool for blitz is just stronger than the player pool for rapid.  I play both and is easily 200 points lower than blitz.  Sure I play a bit worse (5/5 vs 10 minutes), but in analysis, my opponent in blitz (at least the 5/5 game) is playing at higher average accuracy than in 10 minutes game.

I’m 1504 in bullet and only 960 in blitz. Is that strange? I do feel blitz players here are very good or maybe I’m just so bad at blitz.

I've also noticed this recently

I'm a relatively new player and i'm 700-800 in 10 min rapid and only 400-500 in blitz at the moment and the players are much better than 400-500 10 min players and many more know openings than the same level in 10 min 

I have noticed that people who are good at rapid aren't able to improve rapidly at other formats but I would prefer you to stuck at rapid because it would help you a lot at OTB Chess.

Blitz is the ultimate mix of calculation and speed. I  would assume you're taking too long to find the best of the best, instead of finding simple, sound moves. For example, instead of calculating the endless tactical possibilities, try doing something like "I play Rg1, get the open file" or "Nd5, taking an outpost in the center." Very simple, very effective.

Blitz is also testing more of how fast you can think, not only how well you can think. That might be the reason why you have a lower rating in blitz. Also, rapid ratings tend to be higher than blitz ratings, so a 1400 in blitz would be better than a 1400 in rapid.