How long universe last

Register or Log In. The Magazine Shop. Login Register Stay Curious Subscribe. The Sciences. Eventually, black holes will be the last remaining matter in the universe.

Newsletter Sign up for our email newsletter for the latest science news. Sign Up. Already a subscriber? Want more? If probabilities are to work in a multiverse, there must be actual cutoffs that bring various universes to their ends, study leader Bousso says.

According to the formulas used to calculate cutoffs, a universe that is For most people, the idea that a mathematical tool could be elevated to a real-world event might seem strange, but there are precedents for it in physics. For example, Tufts University's Olum said, there was a time when many physicists resisted the idea that protons—subatomic particles with positive charges—are themselves made up of smaller particles called quarks.

Mathematically, quarks help explain the so-called strong force in the nucleus of an atom—and in the real world they now help account for the "zoo" of strange particles that's been discovered in accelerators. Nowadays, though, everybody believes quarks are real fundamental particles. Along the same vein, if theorists believe in eternal inflation, they either need to believe that cutoffs are not valid techniques for computing probabilities—or that cutoffs are real events that predict the end of time, Bousso and colleagues say.

What a real-world cutoff would look like and what form the end of time would take are unclear, the team says. If it happens, it would probably be sudden and unexpected. And even if humans could see a cutoff coming, we almost certainly wouldn't be viewing it from Earth. Scientists think our sun—now a middle-age star at about 4. At that point in time, the sun will run out of fuel in its core and will start to shed its outer layers of gas, inflating to become a red giant and ultimately a planetary nebula.

Earth's exact fate during this event is unclear , but few scientists would argue that life on the planet could survive the sun's death. Although Australian National University's Lineweaver agrees that calculating probabilities in an eternal multiverse is problematic, he doesn't think predicting a real-world cutoff is the solution.

Tufts University's Olum also doesn't think physicists should accept the end of time as inevitable. To me, these things are on equal footing," he said. Inflation aside, there are many theories in physics for how the cosmos might end.

In a "big crunch," for example, the universe would reverse its current expansion and shrink into a black hole. Then there's the "heat death" theory, in which the universe expands forever until it reaches a state of thermal equilibrium, in which nothing can happen. The remaining stars and planets will explode. Finally, the last atoms will be ripped apart. The final doomsday scenario that Mack describes is extremely unlikely: vacuum decay.

That might happen if, say, a black hole evaporates in just the wrong way. Such a bubble would expand at the speed of light, destroying everything, until it cancels the universe. Vacuum decay might already have begun in some distant place. Not to worry, though. News 09 NOV Research Highlight 05 NOV News 04 NOV News 17 SEP Obituary 06 AUG Article 10 NOV By measuring how bright it appears to us on Earth, and knowing light dims as a function of distance, it provides a precise way of measuring the distance to stars.

Read more about how Henrietta Leavitt changed our view of the Universe. Freedman and her team were the first to use Cepheid variables in neighbouring galaxies to our own to measure the Hubble constant using data from the Hubble Space Telescope.

Since then, the value from studying local galaxies has hovered around the same point. If these measurements are correct, then it suggests that the Universe might be inflating faster than theories under the Standard Model of Cosmology allow. It could mean this model — and with it our best attempt at describing the fundamental nature of the Universe — needs to be updated.

At present, the answer is not certain, but if it proves to be the case, then the implications could be profound. If the Standard Model is wrong, one thing it could mean is our models of what the Universe is made up of, the relative amounts of baryonic or "normal" matter, dark matter, dark energy and radiation, are not quite right.

And if the Universe is really expanding faster than we thought, it might be much younger than the currently accepted An alternative explanation for the discrepancy is the part of the Universe we live in is somehow different or special compared to the rest of the Universe, and that difference is distorting the measurements. But astronomers think they are getting close to pinpointing what the Hubble Constant is and which of the measurements is correct.

One is the ESA's space observatory Gaia, which launched in and has been measuring the positions of around one billion stars to a high degree of accuracy. Scientists are using this to work out the distances to the stars with a technique called parallax.

As Gaia orbits the sun its vantage point in space changes, much like if you close one eye and look at an object, then look with the other eye it appears in a slightly different place.

So, by studying objects at different times of the year during its orbit, Gaia will enable scientists to accurately work how fast stars are moving away from our own Solar System. Another facility that will help answer the question of what the Hubble Constant's value is the James Webb Space Telescope, which is due to be launched late in