Dark energy tagged posts

What is the universe made of? This question has driven astronomers for hundreds of years.

For the past quarter of a century, scientists have believed “normal” stuff like atoms and molecules that make up you, me, Earth, and nearly everything we can see only accounts for 5% of the universe. Another 25% is “dark matter”, an unknown substance we can’t see but which we can detect through how it affects normal matter via gravity.

The remaining 70% of the cosmos is made of “dark energy”. Discovered in 1998, this is an unknown form of energy believed to be making the universe expand at an ever-increasing rate.

In a new study soon to be published in the Astronom...

Our universe could be twice as old as current estimates, according to a new study that challenges the dominant cosmological model and sheds new light on the so-called “impossible early galaxy problem.”

“Our newly-devised model stretches the galaxy formation time by a several billion years, making the universe 26.7 billion years old, and not 13.7 as previously estimated,” says author Rajendra Gupta, adjunct professor of physics in the Faculty of Science at the University of Ottawa.

For years, astronomers and physicists have calculated the age of our universe by measuring the time elapsed since the Big Bang and by studying the oldest stars based on the redshift of light coming from distant galaxies...

When Edwin Hubble observed distant galaxies in the 1920s, he made the groundbreaking discovery that the universe is expanding. It was not until 1998, however, that scientists observing Type Ia supernovae further discovered that the universe is not just expanding but has begun a phase of accelerating expansion. “To explain this acceleration, we need a source,” says Joseph Mohr, astrophysicist at LMU...

What happened shortly after the universe was born in the Big Bang and began to expand? Bubbles occurred and a previously unknown phase transition happened, according to particle physicists.

Think of bringing a pot of water to the boil: As the temperature reaches the boiling point, bubbles form in the water, burst and evaporate as the water boils. This continues until there is no more water changing phase from liquid to steam.

This is roughly the idea of what happened in the very early universe, right after the Big Bang, 13.7 billion years ago.

The idea comes from particle physicists Martin S...