unlocked puzzles of science

 Introduction For as long as humans have been grazing at the night sky, the question of how far can see into it has fascinated astronomers. The revolutionary observations made by Edwin Hubble in the late 1920s were the first direct evidence that the universe was not static. The systematically increasing spectroscopic redshift observed in increasingly distant galaxies was a clear sign that the universe expands. Because the universe is expanding, the sphere of what we can see is not defined simply by the age of the universe multiplied by the speed of the light. This is because the universe is expanding ;the distance between every point of the fabric of spacetime is forever increasing, a growth that affects the paths of photons. For a long time this expansion was believed to be slowing down due to the combined gravitational pull exerted by all the matter in the universe. However, at the end of the 1990s the measured dimming of Type la supernovae with increasing redshifts revealed that...