Question

Explain what the two teams of astronomers found in the 1990s. What question did their discovery create?

Answer 1

Two teams of astronomers discovered in the 1990s that the universe is not only expanding but doing so at an accelerated rate, which led to the hypothesis of dark energy and questions about the universe's eventual fate.

Step-by-step explanation:

In the 1990s, two teams of astronomers made a groundbreaking discovery that the universe is expanding. Using innovative techniques to analyze the light from supernovae, they were able to measure distances to galaxies far away and found that these galaxies were accelerating away from each other, implying not just expansion, but an accelerated expansion. This discovery led to the concept of dark energy, a mysterious force that is driving this acceleration, and raised questions about the future of the universe and the ultimate fate of its expansion.

This significant finding was made possible by advancements in technology and collaboration among astronomers. By meticulously studying the spectra of distant supernovae, they could identify key features indicating redshift, which means the light from those celestial bodies is being stretched, or shifted towards the red end of the spectrum, due to them moving away from us. These observations endorse the Big Bang theory, suggesting that the universe was once concentrated in a small area and has been expanding ever since. The unexpected twist was that this expansion was not slowing down, as had been presumed, but instead was speeding up.

The question posed by this discovery is what could be causing this accelerated expansion. The leading hypothesis is the existence of dark energy, an invisible energy that permeates all of space and exerts a repulsive force, which may account for up to 68% of the total energy content of the universe. The discovery of the universe's accelerated expansion was so monumental that it earned the leaders of these two research teams, Saul Perlmutter, Brian P. Schmidt, and Adam G. Riess, the Nobel Prize in Physics in 2011.

Answer 2

There were many discoveries in the 1990's, one of them was carried out by two independent research teams: the Supernova Cosmology Project and the High-Z Supernova Search (This discovery made them win the Nobel Prize in Physics).

Until that moment, the astronomers, including these two teams mentioned before, believed that the expansion of the universe was slowing down, but in their search of supernovas to measure this expansion over time, they discovered that they were wrong: The expansion of the universe was accelerating. But this created another question: What force is driving this behavior in the universe?