When asked for your age, it’s likely you won’t slip with the exception of a recent birthday mistake. But for the sprawling sphere we call home, age is a much trickier matter. Before so-called radiometric dating, Earth’s age was anybody’s guess. Our planet was pegged at a youthful few thousand years old by Bible readers by counting all the “begats” since Adam as late as the end of the 19th century, with physicist Lord Kelvin providing another nascent estimate of million years. Kelvin defended this calculation throughout his life, even disputing Darwin’s explanations of evolution as impossible in that time period. In , Marie Curie discovered the phenomenon of radioactivity, in which unstable atoms lose energy, or decay, by emitting radiation in the form of particles or electromagnetic waves.
Uranium dating suggests new age of universe
The same was long true of the cosmos. The ancient Greeks Eratosthenes and Aristarchus measured the size of the Earth and Moon, but could not begin to understand how old they were. With space telescopes, we can now even measure the distances to stars thousands of light-years away using parallax, the same geometric technique proposed by Aristarchus, but no new technology can overcome the fundamental mismatch between the human lifespan and the timescales of the Earth, stars, and universe itself.
Despite this, we now know the ages of the Earth and the universe to much better than 1 percent, and are beginning to date individual stars. Our ability to measure ages, to place ourselves in time as well as in space, stands as one of the greatest achievements of the last one hundred years. In the Western world, the key to the age of the Earth was long assumed to be the Bible and its account of creation.
Read chapter The age of the universe, dark matter, and structure formation: (NAS with stellar evolution and radioactive dating as age-determination methods.
We’ve all lost track of time at one point or another, but astronomers really go all in. Recent studies show they may have overestimated the age of the universe by more than a billion years — a surprising realization that is forcing them to rethink key parts of the scientific story of how we got from the Big Bang to today. The lost time is especially vexing because, in a universe full of mysteries , its age has been viewed as one of the few near-certainties. By , the European Planck space telescope’s detailed measurements of cosmic radiation seemed to have yielded the final answer: All that was left to do was to verify that number using independent observations of bright stars in other galaxies.
Instead of confirming Planck’s measurements, they started getting a distinctly different result. He estimates that his results, taken at face value, indicate a universe that is only At first, the common assumption was that Riess and the other galaxy-watchers had made a mistake. But as their observations continued to come in, the results didn’t budge.
Reanalysis of the Planck data didn’t show any problems, either. If all the numbers are correct, then the problem must run deeper. It must lie in our interpretation of those numbers — that is, in our fundamental models of how the universe works.
How Old is the Universe?
Most astronomers agree that the observable universe is somewhere between 13 billion and 14 billion years old. Astronomers use several different methods to date the universe. In recent years, results from these differing methods have been coming into closer agreement. One method of determining the universe’s age involves finding the oldest stars and deciphering their ages based on knowledge of how stars are born, evolve, and die.
White dwarf stars are particularly good candidates for these studies.
Scientists use a technique known as radiometric dating. The nuclear age taught us how to blow up stuff real good, but it also helped understand.
Until recently, astronomers estimated that the Big Bang occurred between 12 and 14 billion years ago. To put this in perspective, the Solar System is thought to be 4. Astronomers estimate the age of the universe in two ways: 1 by looking for the oldest stars; and 2 by measuring the rate of expansion of the universe and extrapolating back to the Big Bang; just as crime detectives can trace the origin of a bullet from the holes in a wall.
Astronomers can place a lower limit to the age of the universe by studying globular clusters. Globular clusters are a dense collection of roughly a million stars. Stellar densities near the center of the globular cluster are enormous. If we lived near the center of one, there would be several hundred thousand stars closer to us than Proxima Centauri, the star nearest to the Sun. Text Link to the HST press release describing this image. The life cycle of a star depends upon its mass.
High mass stars are much brighter than low mass stars, thus 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.
Study: Universe Might Be 1.2 Billion Years Younger
Over the past century, astronomers have deduced several ways to estimate the age of the universe. To find the Hubble constant, astronomers observe distant galaxies and measure their distances by using Cepheid variable stars or other objects of known intrinsic brightness as well as how fast they recede from Earth. But there was a problem.
Since astronomers at that time did not yet know the universe was expanding (and Einstein himself was philosophically unwilling to accept a.
You may have heard that the Earth is 4. This was calculated by taking precise measurements of things in the dirt and in meteorites and using the principles of radioactive decay to determine an age. This page will show you how that was done. Radioactive nuclides decay with a half-life. If the half-life of a material is years and you have 1 kg of it, years from now you will only have 0. The rest will have decayed into a different nuclide called a daughter nuclide.
Several radioactive nuclides exist in nature with half-lives long enough to be useful for geologic dating. This nuclide decays to Strontium Sr87 with a half-life of
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September 12, The universe is looking younger every day, it seems. New calculations suggest the universe could be a couple billion years younger than scientists now estimate, and even younger than suggested by two other calculations published this year that trimmed hundreds of millions of years from the age of the cosmos.
Most astronomers would agree that the age of the Universe – the time elapsed since This method works in a way similar to the well-known Carbon dating in.
Thank you for registering If you’d like to change your details at any time, please visit My account. The first measurement of uranium outside our solar system suggests that the universe is at least Just as the radioactive decay of carbon is used for dating archaeological remains, astronomers are using the decay of uranium, which has a half-life of 4. By measuring the uranium line in the spectrum of a star and comparing it to the amount of other stable elements, it is possible to calculate the age of the star.
This benchmark is interesting to astronomers because it is independent of models of stellar evolution. In the past, this method has not been possible because the amount of uranium in stars is tiny and its spectral lines are hidden by emission from more abundant elements. The results give an age of
How are the ages of the Earth and universe calculated?
In a study published in the Astronomical Journal , researchers used empirical data, in this case observable measurements on the distance from Earth of 50 galaxies, to tweak a year-old computational tool called the Hubble constant to measure the expansion of the universe. The idea is to compute how long it would take all objects to travel backward to the beginning. A more recent technique uses observations of leftover radiation from the Big Bang. It maps echoes in spacetime, known as the cosmic microwave background, and reflects conditions in the early universe as set by the Hubble constant.
These dating techniques, which are firmly grounded in physics and are the age of the Universe (based on the recession of distant galaxies).
Creationist’s Blind Dates. The standard scientific estimate is that the universe is about 15 billion years old, the earth about 4. It is important to recognize from the start that there are independent procedures for obtaining each of these estimates, and that the procedures yield ranges of values that overlap. In the case of the universe, estimates can be obtained from astronomical methods or considerations of nuclear reactions.
Astrophysicists can measure the rate at which galaxies are receding and use these measurements to compute the time needed for the universe to expand to its present size. A second, independent, astronomical method is to use standard techniques to measure some parameters of stars mass, luminosity, compositor, and surface temperature , from which a well-confirmed theory of the life histories of stars enables physicists to compute their.
Finally, considerations of radioactive decay make it possible to calculate the time at which certain heavy elements were formed.