1. A helmet protector used in combination with a conventional helmet having a hard helmet outer layer adapted to be exposed to the atmosphere and configured to directly contact with another hard helmet outer layer of another helmet or another helmet protector when being worn by a user, the helmet protector comprising: a helmet protector cover, the helmet protector cover comprising a hard helmet protector layer, the helmet protector cover surrounding at least a portion of the helmet and defining an air space extending between the hard helmet protector cover layer and the hard helmet outer layer when the helmet protector is installed onto the helmet, the helmet protector cover having at least one opening providing an air passageway from the air space to the atmosphere located outside the helmet protector; and a plurality of spacers separating the helmet protector cover away from the helmet when the helmet protector is installed directly on the hard helmet outer layer of the conventional helmet, each of the plurality of spacers being separate discrete spacers spaced apart from each other and located at different positions on the helmet protector cover, and bridging the helmet and helmet protector cover through the air space when the helmet protector is installed on the helmet, wherein the air space surrounds the spacers and is unobstructed between the hard layer of the helmet protector cover and the hard helmet outer layer when the helmet protector is installed on the helmet to allow for propagation of waves generated by an impact to the hard outer layer of the helmet protector cover through the unobstructed air space to the hard helmet outer layer of the helmet, which reflects the waves back through the unobstructed air space and then exiting through the at least one passageway of the helmet protector to the outside atmosphere to dissipate energy from the impact to the helmet protector.
2. The helmet protector according to claim 1 , wherein the at least one air passageway is a plurality of openings.
3. The helmet protector according to claim 2 , wherein each spacer is located between a pair of adjacent openings through the helmet cover.
4. The helmet protector according to claim 2 , wherein the plurality of openings are spaced apart on the helmet cover.
5. The helmet protector according to claim 4 , wherein the plurality of openings are arranged in a pattern on the helmet cover.
6. The helmet protector according to claim 5 , wherein the plurality of openings are arranged in a matrix pattern on the helmet cover.
7. The helmet protector according to claim 6 , wherein each spacer is located between four openings in a square arrangement of the matrix pattern on the helmet cover.
8. The helmet protector according to claim 1 , wherein the at least one air passageway is a round through hole in the helmet cover.
9. The helmet protector according to claim 1 , wherein the at least one opening air passageway is configured to allow a shock wave to exit the air space through the helmet cover.
10. The helmet protector according to claim 1 , wherein the hard outer layer of the helmet cover is a single layer made of the hard material.
11. The helmet protector according to claim 10 , wherein the at least one connector is configured to removably connect the helmet protector to the helmet.
12. The helmet protector according to claim 1 , further comprising at least one connector for connecting the helmet protector to the helmet.
13. The helmet protector according to claim 12 , wherein the at least one connector is configured to grip a lower edge of the helmet to retain the helmet protector onto the helmet.
14. The helmet protector according to claim 1 , wherein the at least one connector is a plurality of connectors.
15. The helmet protector according to claim 14 , wherein the plurality of connectors comprise a pair of side connectors and a front connector and a rear connector.
16. The helmet protector according to claim 1 , wherein the helmet protector is configured so that the helmet nests within the helmet protector.
17. The helmet protector according to claim 16 , wherein the air space and spacers separate the entire helmet cover from the helmet when the helmet cover is installed on the helmet.
18. The helmet protector according to claim 1 , wherein at least one spacer is located adjacent to a front edge of the helmet protector.
19. The helmet protector according to claim 1 , wherein at least one spacer holds the helmet cover off or away from an outer surface of the helmet to provide a side opening between the air space and atmosphere.
20. The helmet protector according to claim 1 , wherein each spacer is attached inside the helmet protector.
21. A helmet protector comprising the conventional helmet and the helmet protector according to claim 1 , the helmet protector being fitted onto the conventional helmet.
22. The helmet protector according to claim 1 , wherein the spacers are circular-shaped and the air space surrounds round sides of the spacers within the air space.
23. A helmet protector used in combination with a conventional helmet having a hard helmet outer layer adapted to be exposed to the atmosphere and configured to directly contact with another hard helmet outer layer of a helmet or another helmet protector when being worn by a user, the helmet protector comprising: a helmet protector cover, the helmet protector cover comprising a hard helmet protector cover layer, the helmet protector cover surrounding at least a portion of the helmet and defining an air space extending between the hard helmet protector cover layer and the hard helmet outer layer when the helmet protector is installed onto the helmet, the helmet protector cover comprising a plurality of openings defined by through holes providing a plurality of air passageways from the air space to the atmosphere located outside the helmet protector; and a plurality of spacers separating the helmet protector cover from the helmet when the helmet protector is installed directly on the hard helmet outer layer of the conventional helmet, each of the plurality of spacers being separate discrete spacers spaced apart from each other and located at different positions on the helmet protector cover, and bridging the helmet and the helmet protector cover through the air space when the helmet protector is installed on the helmet, the plurality of spacers being located at different positions on the helmet protector cover relative to locations of the through holes, wherein the air space surrounds the spacers and is unobstructed between the hard helmet protector cover and the hard helmet outer layer when the helmet protector is installed on the helmet to allow for propagation of waves generated by an impact to the helmet protector cover through the unobstructed air space to the hard helmet outer layer, which reflects the waves back through the unobstructed air space and then exiting through the plurality of openings of the helmet protector cover to dissipate energy from the impact to the helmet protector.