Monthly Archives: January 2016

astrobiology, extra-terrestrial life

It’s Hard out there for an Alien

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No Calls From ETs?  They Might Be Extinct

parkes telescope looks for alien life signals
CSIRO Parkes radio telescope searches for alien signals. Courtesy CSIRO/Wayne England.

I know it’s a tough call for the alien fans out there (and I have to confess, I DO think that there’s life out there somewhere), but a group of astrobiologists led by Dr. Aditya Chopra and Professor Charley Lineweaver (at Australian National University) has predicted that life on distant worlds isn’t being found because it’s likely to be extinct already. If what they’re saying is true, then the galaxy could be a pretty sparsely populated place indeed.

Extinction seems like a tough fate, but think about where life typically is expected to arise: newborn planets. Such places are not tranquil neighborhoods where happy little baby microbes flourish and evolve to become multi-celled life, and eventually grow up to build Starbucks franchises everywhere.

No, these infant worlds are harsh places. Really harsh. They get blasted by their stars (which themselves are young and feisty). Their atmospheres are toxic to most (if not all) forms of life.  They might lose their magnetic fields, and then their atmospheres. Or, they might suffer incredible impacts that melt the surface over and over again. Whatever happens, when conditions do settle down and allow the formation of simple microbes, things can change through rapid global cooling and heating. These episodes can easily wipe out any simple one-celled life forms before they have a chance to take the first step up the evolutionary ladder. These early life forms can be quite fragile, and may not evolve quickly enough to ride out the swift changes on their home worlds.

Worlds and  Alien Life

The science of astrobiology looks at the conditions needed to make a world welcome (or at least less-hostile) to life. A habitable world needs warmth, water, and some sort of food for the life to eat (and that can take many forms). It also has to have some way to regulate the greenhouse gases in its atmosphere to keep the surface relatively temperate so life can take hold and spread. That’s tough to do when the early atmospheres are so unstable. Yet, Earth managed to do it — albeit with a few mass extinctions along the way. Life still took hold and thrives today.

Smacking Down Life in our Solar System

The “perfect” places for life to arise do exist in the galaxy. Wet, rocky planets are out there. Many have the “stuff” needed to created and sustain life. It certainly worked on Earth, but our planet may have gotten lucky. And, the fact that we just haven’t gotten any signals from life forms whose microbial and multi-celled ancestors survived the turbulent early years of their planets, has raised questions for years.

Look at the other planets that formed in our neighborhood: Venus and Mars. They had the same ‘starting assets’ as Earth, but Venus took a wrong turn and now it’s a hellish volcanic planet smothered in heavy CO2 clouds and sulfuric acid rains. Mars went the other way, lost its magnetic field, then its atmosphere, and froze. No life has been found on either world, although it’s possible we might find remains of ancient microbial life on Mars. If it did exist there, it didn’t adapt fast enough or work to stabilize its environment. Life did help stabilize Earth’s early climate, and that helped make it much more habitable for the life forms that did evolve.

Cutting the Signal from Alien Life Before it Starts

If it’s true that infant planets don’t provide a good place for life, or that the life that does manage to rise up can’t survive the unstable climate changes on those baby worlds, then this might explain why we haven’t gotten any hint of intelligent life “out there”. It may not have actually have had time to arise, or its predecessors were snuffed out. Researchers have called this problem the “Gaian Bottleneck”, which is a colorful term for early extinction on nearly all young planets.

If this bottleneck really is occurring, then when and if we DO get to other worlds (Mars and beyond), we may well find a lot of fossils of extinct microbes. That’s because life forms such as humans, dogs, cats, cows, horses, whales, flowering plants, trees, insects, and so on, take millions of years to evolve. If their predecessors rise up on a planet with an inhospitable, rapidly changing environment, there just isn’t going to be enough time for intelligent life to evolve.

It’s an interesting idea, this Gaian Bottleneck. The longer we go without a signal or trace of life elsewhere in the universe, the more scientists may have to admit that time is not on the side of intelligent life that can send signals out to announce its presence. And, as someone who things that there probably IS out there, this theory may explain that — even if there ARE aliens out there — they may be much rarer than we hoped.

astronomy, astronomy news, dwarf planets, Kuiper Belt, planetary science, planets, Pluto

Ninth Planet!!! Well….possibly….

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Computer Models Predict a Massive World beyond Neptune

Planet "Nine"
This artistic rendering shows the distant view from Planet Nine back towards the sun. The planet could be be gaseous, similar to Uranus and Neptune. Hypothetical lightning lights up the night side.
Credit: Caltech/R. Hurt (IPAC)

The big news today involves a new world in the outer region of the solar system called the Kuiper Belt. Although it hasn’t actually been seen yet, planetary scientists at California Institute of Technology (CalTech) announced that they’ve found evidence for what may be a giant planet on a weird orbit out in the far reaches of our own solar system. Let that sink in for a moment.

If it turns out this object really exists, then it would be a candidate for planet-hood. Not only that, but it would help fill in a gap in early solar system history. It’s quite possible that this world formed as one of five planetary “cores”. Four of them ended up as Jupiter, Saturn, Uranus, and Neptune. “Core 5” could have gotten too close to one of the other gas giants early in the solar system’s history, and gotten gravitationally kicked out to its present orbit in the far reaches of the Kuiper Belt. This is all very exciting news, even if this world hasn’t quite been seen through telescopes yet.

The Skinny on “Planet Nine”

Here’s what happened. Two planetary scientists at CalTech — Konstatin Batygin and Mike Brown (who has discovered several worlds in the Kuiper Belt and is famous for claiming to have “killed” Pluto) — deduced the existence of this world by using mathematical models and computer simulations based on observational data of other worlds in the Kuiper Belt. It’s so massive they’ve nicknamed it “Fatty” (although the official “unofficial” name in their paper is “Planet Nine”). It could be the remnant of a “super-Earth” that formed early in the solar system’s history. The object has a mass about 10 times that of Earth. It orbits about 20 times farther from the Sun on average than Neptune does, andwould take between 10,000 and 20,000 years to go once around the Sun.

Finding Fatty

p9_kbo_orbits_labeled_1_
The six most distant known objects in the solar system with orbits exclusively beyond Neptune (magenta) all mysteriously line up in a single direction. Also, when viewed in three dimensions, they tilt nearly identically away from the plane of the solar system. Batygin and Brown show that a planet with 10 times the mass of the earth in a distant eccentric orbit anti-aligned with the other six objects (orange) is required to maintain this configuration. Caltech/R.Hurt (IPAC). Diagram created using Worldwide Telescope.

The road to Fatty’s discovery began when Brown noticed a peculiar effect that showed up in the orbits of 13 Kuiper Belt objects. At first, he and others who had seen this effect suspected that there was another smaller object orbiting farther out that was putting the kink in the orbits of other worlds. So, Brown and Batygin began working on computer simulations of what could be causing the effect.

To give you an idea of what’s happening, think about the orbits of the known planets. All of them move more or less in the plane of the solar system. Pluto does not — it’s on a highly elliptical and eccentric orbit (meaning it’s orbiting through the plane, not quite perpendicular). That indicates it may have been “kicked out” of its original formation region by the combined action of Jupiter or Neptune, early in solar system history.

Things get weird when you get out to the Kuiper Belt, the region where Pluto, Eris, Makemake, and other dwarf planets orbit. Six very distant KBO worlds observed by astronomers Chad Trujillo and Scott Shepherd all have elliptical orbits, which most planets do. However, those orbits “point” in the same direction, as if they all lined up together. They’re also tilted in the same direction and point about 30 degrees downward from the plane of the solar system. They’re perpendicular to the plane. The chances of both orbital “quirks” are pretty small and point to the idea that something farther out is shaping those orbits.

The concept of distant objects messing with the orbits of closer-in worlds isn’t a new one. Before Pluto was discovered, the idea of a “Planet X” sent astronomers looking for something beyond Neptune, and Clyde Tombaugh found Pluto through this search. The idea of predicting a planet’s existence with mathematics isn’t new either. Neptune was also predicted mathematically in 1846 by Urbain Le Verrier. It turned out Neptune was observed earlier, but no one realized it was a planet. In the case of this new world, if it exists, it seems to be having a gravitational impact on the six worlds closer in. So, Brown, Batygin and others are following in some hallowed and very scientific footsteps with their mathematics and computer models.

The next step was to figure out what was doing the influencing. One idea was that several distant Kuiper Belt objects (as yet unseen or undiscovered) could have enough mass and gravitational pull to mess with the orbits of the “distant six”. That idea didn’t work out because it would require quite a bit more mass in the Kuiper Belt than actually exist. About 100 times more, to be exact. So, the two scientists decidd to try doing computer simulations of the orbits using a giant world as the perturber. It worked, and they came pretty close to mimicking the weird orbits.

If this world exists, it not only explains the weirdness of the six orbits it influences, but also may be the reason why Sedna and 2012 VP (another Sedna-like world) have orbits that are a bit extraordinary as well. These and others do NOT follow orbits that would be expected of Kuiper Belt objects that were “kicked out” by gravitational interactions with Neptune early in the solar system’s history. Instead, some are quite perpendicular to the plane of the solar system, and that is likely to happen if they’re being influenced by a large, distant world.

The story is still unfolding, folks. As I’ve said several times here, this world hasn’t been observed, yet. Until it’s actually seen, we can’t even be sure it’s a planet. By IAU standards it must be self-rounded by its own gravity, orbit the Sun AND have cleared its orbit of debris. We kow it orbits the Sun. The other two aspects need to be proven.

But, its effects on the orbits of other worlds has certainly indicated something is “out there”. And that’s enough to start people looking along the path of the supposed orbit of this world to see if what’s really there. So, stay tuned! Our perception and understanding of the solar system are about to change again!

Caveat WhackJob

Now, before all the N*ancy-bots and Nibiru-huggers start spamming me with cosmic reassurances that they’ve already seen this thing coming and it’s populated with aliens with wiggly tongues or something, I want to point out again: this world has NOT been observed, yet. So, you can’t claim to have spotted it either. NO ONE has seen this world. But, trained astronomers have seen its gravitational effects on the orbits of other worlds, and eventually it will be observed. This is completely, scientifically normal and nothing to start writing conspiracy theories about.