The guys are bouncing a light beam from a laser to a mirror on the moon and back to a parabolic receiver which is sitting behind the laser on the roof of their apartment building. This requires that both the laser and the parabolic receiver be pointed at the same angle at the moon in the sky, but the laser is set at a much lower angle than the receiver is, so one of them cannot be pointed at the moon.
When Sheldon is toasting the English muffins using the Cylon toaster, there is no Cylon marking as happens when he toasts the bread in "The Cornhusker Vortex"
When Leonard opens the elevator door, it can be mistakenly believed the back of the staircase set is shown and not a dark elevator shaft. However, the staircase wall is brown/rust-colored bricks, while the back of the elevator shaft is grey bricks and noticeably closer.
Leonard tosses his bottle down the elevator shaft and calculates the distance as 30 feet. This is either too small or too large.
If the car is above (as the previous episode showed Leonard pressing Up to call it when it broke), this is 10 feet per floor for 3 flights below the two apartments, which is barely believable if not for the pit required below every elevator, a height of 4-6 feet. This could reduce the height per flight as low as only 8 feet.
If the car is below (if the elevator fell in the previous episode) the bottle would have smashed on the roof of the elevator car, which would be just below the second floor, 2 flights away, or 15 feet per floor, or floors close to 3 times the height of Leonard or Howard.
If the car is above (as the previous episode showed Leonard pressing Up to call it when it broke), this is 10 feet per floor for 3 flights below the two apartments, which is barely believable if not for the pit required below every elevator, a height of 4-6 feet. This could reduce the height per flight as low as only 8 feet.
If the car is below (if the elevator fell in the previous episode) the bottle would have smashed on the roof of the elevator car, which would be just below the second floor, 2 flights away, or 15 feet per floor, or floors close to 3 times the height of Leonard or Howard.
Sheldon tells Zack that Einstein hoped his research work on lasers would produce a device that would be "bitchin'". This is clearly a sarcastic remark. Sheldon famously doesn't understand sarcasm and wouldn't make such a remark.