A Beginner's Guide to the Universe

 

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Early Universe Had Slower Time

A phenomenon called cosmological time dilation means that events taking place in the early universe seem to evolve slower than those today.

Time seems to have ticked more slowly when the universe was young, according to observations of ancient astronomical objects that appear to evolve at a fifth of the rate we see today.

The idea that time appears to be slower in the past sounds odd, but it is a direct consequence of the expansion of the universe since the big bang. This expansion means that light from ancient cosmic events must travel increasingly longer distances to reach Earth, and therefore takes more time to arrive. 

As a result, cosmic events that are extremely distant or far back in time appear to unfold more slowly compared to the same event happening nearby, right now. 

That isn’t to say the early universe was in slow motion, however – anyone present billions of years ago would have seen time evolving normally. Source: New Scientist (for registered users) TO READ MORE, CLICK HERE...

Alien Fragments

In 2014, an interstellar object – thought to be from another star system – streaked across Earth’s skies as a meteor, then crashed into the Pacific Ocean near Papua New Guinea. 

Harvard astronomer Avi Loeb is now leading a sea-going search, combing the ocean floor with what’s essentially a large magnet, hoping to pick up fragments of that object. He’s found bits of wire, tiny aluminum shards and volcanic ash. 

And this week (June 21, 2023), Loeb reported that his team has found tiny metallic spherules whose composition suggests an unearthly origin.

Loeb posted the news in his onboard diary, which is published at Medium. He included a photo of a few of the odd objects, which are minuscule, only about 0.3 mm (about one-hundredth of an inch) in size. And he added a couple of more photos in his latest post on June 22.

Becky Ferreira also wrote about the discovery for Vice on the same day.

Loeb likens the search to “finding a needle in the ocean.”   READ MORE...

Exoplant Clouds

Using data from multiple telescopes, scientists have detected clouds on a gas giant exoplanet some 520 light-years from Earth. So detailed were the observations, they even discerned the altitude of the clouds and the structure of the upper atmosphere, with the greatest precision yet.

It's work that will help us better understand exoplanet atmospheres – and look for worlds that may have conditions hospitable to life, or biosignatures in their spectra. We're also getting closer to making weather reports for distant alien worlds.

The exoplanet in question is WASP-127b, discovered in 2016. It's a hot and therefore puffy beast, orbiting so close to its star that its year is just 4.2 days. The exoplanet clocks in at 1.3 times the size of Jupiter, but only 0.16 times Jupiter's mass.

This means that its atmosphere is somewhat thin and tenuous – perfect for trying to analyze its contents based on the light that streams through it from the exoplanet's host star.

To do this, a team of researchers led by astronomer Romain Allart of the Université de Montréal in Canada combined infrared data from the space-based Hubble Space Telescope, and optical data from the ESPRESSO instrument on the ground-based Very Large Telescope, to peer into different altitudes of WASP-127b's atmosphere.

"First, as found before in this type of planet, we detected the presence of sodium, but at a much lower altitude than we were expecting," Allart said.  TO READ MORE, CLICK HERE...

Planet Vulcan

In 1846, astronomer and mathematician Urbain Le Verrier sat down and attempted to locate a planet that had never been seen before by humans. Uranus (grow up) had been moving in unexpected ways, as predicted by the Newtonian theory of gravity.

Though the discrepancies were small, there was a difference between the observed orbit of Uranus and the way Newtonian physics predicted its orbit to be. In July, Le Verrier proposed that the difference could be explained by another planet beyond Uranus, and made predictions as to the orbit of this previously unknown body.

Being a mathematician first and an astronomer second, he wasn't really interested in finding it with a telescope now that he'd found it in maths, and the task of searching for it was left to German astronomer Johann Gottfried Galle. On September 23, 1846, Galle looked at the spot Le Verrier had predicted the planet would be, and found to within 1 degree of the spot... the planet Neptune.

So, having discovered a new planet by looking at the orbit of another, Le Verrier was called upon to take a look at a planet whose name doesn't also mean butt hole: Mercury. Mercury, being so close to the Sun, is the most difficult planet in our Solar System to observe (assuming there is no Planet Nine out there). Le Verrier was tasked with plotting Mercury's orbit using Newtonian physics.

But he couldn't. No matter how much he tried, Mercury's eccentric orbit didn't make any sense. According to Newtonian theory, the planets move in elliptical orbits around the Sun, but observations showed that Mercury's orbit wobbles more than could be accounted for by the gravity exerted by the other known planets.  TO READ MORE, CLICK HERE...