Astronomers May Have Just Discovered the First Moon Beyond Our Solar System

We have the strongest evidence yet for a moon orbiting a planet outside of our solar system. This moon — if it exists — would be about the size of Neptune, which makes it kind of an oddball. But if there’s one thing we’ve learned about the nearly 4,000 exoplanets we’ve found outside of our solar system so far, it’s that there’s a lot of variation out there. So why not expect some strange exomoons in the bunch?

Playing with Light

This possible exomoon — it still needs to be confirmed — orbits a planet 8,000 light-years away from us. The planet is known as Kepler-1625b, and a paper based on the research was published in the journal Science Advances. How astronomers found its moon is a little complicated.

Often, scientists find distant planets by looking at a pattern of brightening and dimming as the planet passes in front of its star. So how about a moon?

There are two pieces of evidence from the Hubble Space Telescope that suggest a moon is lurking nearby. First is the variation of light. Over 19 long hours, Hubble observed the planet passing across its star. About 3.5 hours after the planet went by, there was a second and smaller dimming. As lead author David Kipping of Columbia University suggested in a statement, this variation suggests “a moon trailing the planet like a dog following its owner on a leash.”

The second piece of evidence deals with the timing of the planetary “transit” (the time when the planet passed across the star), which varied wildly from what astronomers expected. The Kepler space telescope had been watching Kepler-1625b for four years, so the astronomers had a good idea of how it should behave.

Hubble discovered that the planet passed across its parent star about 1.25 hours earlier than scheduled. This often happens when a planet has a moon in orbit around it, because it causes the planet to wobble from its predicted location in space. “An extraterrestrial civilization watching the Earth and moon transit the sun would note similar anomalies in the timing of Earth’s transit,” said Kipping, who is also a well-regarded exoplanet researcher.

The astronomers caution that more evidence is needed to confirm this exomoon. For example, we might be looking not at a moon, but at a second planet in the same star system. But then again, maybe not. After all, the Kepler telescope didn’t find any evidence for a second planet in its four years of work, so why should Hubble in 19 hours?

Artists’ impression of the exoplanet Kepler-1625b transiting the star with the candidate exomoon in tow.

Dan Durda

Artists’ impression of the exoplanet Kepler-1625b with its large hypothesized moon. The pair have similar mass and radius ratio to the Earth-Moon system but scaled up by a factor of 11.

Dan Durda

Why So Big?

This Neptune-sized moon, if it exists, seems unimaginably large. Neptune is an incredible four times larger in diameter than our own planet. Further, Neptune has 13 confirmed moons of its own! How can a distant solar system have a moon so ginormous that it’s the size of a gas-giant planet?

Well, strange planets are nothing new, so we wouldn’t expect less of a distant moon, would we? Other solar systems have “hot Jupiters,” which are Jupiter-sized gas giants that orbit right next to their star. In our solar system, we only have small, rocky worlds in that zone, so it’s a little hard to imagine a planet like Jupiter ending up there. Other solar systems also have exotic exoplanets such as super-Earths, which are rocky worlds bigger than Earth and smaller than Neptune. We don’t know of any super-Earths in our own solar system.

And here’s the other thing to remember: The moon is probably Neptune-sized, but it’s puny compared to the mass of its parent planet. The moon is likely about 1.5 percent the mass of the planet it’s orbiting around. Relatively speaking, that’s the same mass difference between the Earth and our own moon, even though both this exoplanet and this exomoon are much larger.

Could aliens be living on this moon and planet? Sadly, the answer is “unlikely.” The planet and moon do lie inside of the star’s “habitable zone,” where water could exist on a rocky planet’s surface. Unfortunately, the moon is gaseous and way too big to host life as we know it — which means it’s likely the same sad situation for life on the planet.

Still, life or not, this possible exomoon might be one of the top scientific discoveries of 2018. All we need to do is get it confirmed. Shall we get started?

 

Written by Elizabeth Howell October 3, 2018

“How Will the Universe End?”- Possibilities –

There are plenty of ideas as to how the universe began, but how will it end? Chances are it won’t go on existing for eternity. Billions of years after we’re gone (if we’re lucky), what exactly will happen to the stars and galaxies we know? Here are four possibilities — some scarier than others.

ClaudioVentrella / iStock / Getty Images Plus

Closing Time

We know the universe won’t last forever because we can look back in time and see how it’s changed. Because it takes time for light to travel from distant galaxies to our telescopes, the light we receive is already old — billions of years old, in some cases. That means that if those telescopes can reach far enough into the universe, we can see the way the universe was billions of years ago. What we see is that galaxies used to be closer together than they are today, and everything has been moving away from everything else faster and faster as time has gone on.

That’s one piece of evidence that the universe is expanding at an accelerating rate. Scientists aren’t sure what the mysterious force is that’s causing this, but they’ve given it a name: dark energy, which is some sort of substance or field that exerts a sort of reverse gravity. It pushes while gravity pulls. But the universe can’t go on expanding forever. Something’s gotta give, and when it does, it’ll likely happen in one of these ways.

Heat Death

An expanding cloud of smoke eventually dissipates into nothingness, and that’s exactly what will happen to our universe if it succumbs to heat death. If there’s enough dark energy in the universe, it will cause everything to keep moving farther and farther away from everything else. Galaxies will no longer be visible to each other and new stars will stop forming. Eventually, the atomic particles that make up everything will decay into subatomic particles, and those subatomic particles will move so far away from each other that they can no longer interact.

The universe will be dark, cold, and motionless, which is why this scenario is also called “The Big Freeze.” In fact, the “heat” part is solely in reference to the fact that it’s the result of entropy, not the temperature that would result. This is the most likely fate for our universe.

The Big Crunch

We assume that dark energy has pretty much leveled off to become a constant force. But what if it hasn’t? If dark energy were to weaken to a point where it couldn’t counteract the force of gravity, the opposite would happen. In the Big Crunch, the expansion of the universe eventually reverses. Galaxies would get closer and closer together, eventually colliding with each other and collapsing under the force of their own gravity. All of the matter in the universe would fall in on itself until everything went back to the way it began: as a singularity, an infinitely dense speck. Given what we know about dark energy, the chances of a Big Crunch are fortunately slim.

The Big Rip

In the heat death of the universe, dark energy is more or less constant. In the Big Crunch, it weakens. In the Big Rip, dark energy gets stronger over time, making it so galaxies not only move away from each other but start expanding from within. Galaxies, stars, and planets would be ripped apart, and eventually, dark energy would become so powerful that it would tear apart molecules and atoms.

“If the Big Rip is coming, it’s not coming for a very long time,” said theoretical astrophysicist Katie Mack in a talk at the NECSS conference in July. “We have at least 120 billion years before we have to worry about this. So you can rest easy — it’ll be a while.”

Vacuum Decay

While the last three scenarios wouldn’t occur for billions of years, vacuum decay could happen at any moment. It’s based on the nature of something called the Higgs field, which permeates our universe and varies in strength based on its potential. You can think of its potential like water in a waterslide. The higher up the waterslide you go, the more energy the water has. When it reaches the very lowest energy possible — say, into the pool at the bottom — you’d call that the vacuum state. Here’s the problem: There are two possibilities for the vacuum state of the universe. It might be a true vacuum, in which case the energy of the Higgs field really is the lowest it can go. We’re chilling out in the pool at the bottom of the slide. But it also might be a false vacuum, in which case there’s another lower-energy state we don’t know about — the pool happens to have a giant bathtub plug, and pulling it can make all of the water rush into an even lower state.

If an event with enough energy occurs in the universe at any time, it could pull that plug. Even more alarming, it could happen without any prodding at all: Quantum particles have the ability to “tunnel” through a barrier, whether from one side of a wall to another or from one vacuum state to another, so random quantum fluctuations could do this too.

“That would be bad,” Mack said, “because the true vacuum has different constants of nature than the false vacuum. Constants of nature are things like the charge of the electron or the mass of the particles or even the strength of gravity sometimes. So if you take the molecules that you’re made of and put them into a true vacuum state, those molecules don’t hold together anymore. Total destruction.”

All it would take is one lone particle flitting off to somewhere it shouldn’t, and reality would cease to exist. Sweet dreams!

What does dark energy do? https://rumble.com/v4g4w5-s2-ep5-what-does-dark-energy-really-do.html

Written by Ashley Hamer August 3, 2018