Obtaining the best image of the infant universe helps scientists better understand the origins of the universe, how we got to where we are on Earth, where we are going, how the universe may end and when that ending may occur, according to a statement from Stony Brook University. Out of this world: 'Nearby' star may have three Super-Earths. By using observations from the Atacama Cosmology Telescope ACT in Chile, the new findings match the measurements of the Planck satellite data of the same ancient light.
The ACT team estimates the age of the universe by measuring its oldest light. All of the stars in a globular cluster formed at roughly the same time, thus they can serve as cosmic clocks. If a globular cluster is more than 20 million years old, then all of its hydrogen burning stars will be less massive than 10 solar masses.
This implies that no individual hydrogen burning star will be more than times brighter than the Sun. If a globular cluster is more than 2 billion years old, then there will be no hydrogen-burning star more massive than 2 solar masses. The oldest globular clusters contain only stars less massive than 0.
These low mass stars are much dimmer than the Sun. This observation suggests that the oldest globular clusters are between 11 and 18 billion years old. The uncertainty in this estimate is due to the difficulty in determining the exact distance to a globular cluster hence, an uncertainty in the brightness and mass of the stars in the cluster.
Another source of uncertainty in this estimate lies in our ignorance of some of the finer details of stellar evolution. Presumably, the universe itself is at least as old as the oldest globular clusters that reside in it. The Hubble constant is a measure of the current expansion rate of the universe.
Cosmologists use this measurement to extrapolate back to the Big Bang. This extrapolation depends on the history of the expansion rate which in turn depends on the current density of the universe and on the composition of the universe. If the universe is flat and composed mostly of matter, then the age of the universe is. The life of a star depends upon its mass. High mass stars are much brighter than low mass stars; they rapidly burn through their supply of hydrogen fuel.
A star like the Sun has enough fuel in its core to burn at its current brightness for approximately 9 billion years. A star that is twice as massive as the Sun will burn through its fuel supply in only million years. A 10 solar mass star, a star that is 10 times more massive than the Sun, burns nearly a thousand times brighter and has only a 20 million year fuel supply.
Conversely, a star that is half as massive as the Sun burns slowly enough for its fuel to last more than 20 billion years. So if a globular cluster is more than 10 million years old, then all of its hydrogen burning stars will be less massive than 10 solar masses. This implies that no individual hydrogen-burning star will be more than 1, times brighter than the Sun.
If a globular cluster is more than 2 billion years old, then there will be no hydrogen-burning stars more massive than 2 solar masses. The oldest globular clusters contain only stars less massive than 0. These low-mass stars are much dimmer than our Sun. This is extremely close to the However, previous measurements of the motion of galaxies have shown that the universe is expanding faster than this, according to the same statement.
This gives us more confidence in measurements of the universe's oldest light. This work was published Dec. Email Chelsea Gohd at cgohd space.
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