Uploaded December 2020 | Updated September 2026, 36 minutes ago
According to the big bang model of the universe, astronomers believed that the expansion of our universe might continue forever, or eventually decrease over time given that there was enough mass and therefore enough self-gravity in the universe to be able to reverse and cause a Big Crunch. But most cosmologists rejected the idea of the big crunch since data-supported evidence for an expanding universe at an ever-slowing rate.
But in 1929, Edwin Hubble made a groundbreaking discovery about our universe. He observed that the wavelength of light emitted by distant galaxies shifted to the red end of the electromagnetic spectrum as it travels through space. He found that the further away a galaxy was from Earth the larger the redshift in its wavelength. This implied that our universe was not slowing down at all. In fact, it was accelerating. The redshift in further away galaxies shows that the wavelength of light must be stretched by the expansion of space itself. So, what was causing space to expand? Well, scientists think that there might be a mysterious force behind it called ‘dark energy’. Let us look at what we know about dark energy so far.
According to the big bang model of the universe, astronomers believed that the expansion of our universe might continue forever, or eventually decrease over time given that there was enough mass and therefore enough self-gravity in the universe to be able to reverse and cause a Big Crunch. But most cosmologists rejected the idea of the big crunch since data-supported evidence for an expanding universe at an ever-slowing rate.
But in 1929, Edwin Hubble made a groundbreaking discovery about our universe. He observed that the wavelength of light emitted by distant galaxies shifted to the red end of the electromagnetic spectrum as it travels through space. He found that the further away a galaxy was from Earth the larger the redshift in its wavelength. This implied that our universe was not slowing down at all. In fact, it was accelerating. The redshift in further away galaxies shows that the wavelength of light must be stretched by the expansion of space itself. So, what was causing space to expand? Well, scientists think that there might be a mysterious force behind it called ‘dark energy’. Let us look at what we know about dark energy so far.
