The Galaxy is a Crowded Place – A Series

[Irishman]

The Galaxy is a Crowded Place – A Series

One of the things that mankind’s search for exoplanets – planets located outside our own solar system – has shown us is that there are a lot more of them out there than we initially thought.

As of this morning, we've found 1,774 exoplanets, a good chunk of them (962) found by the Kepler mission! They have a backlog of about 3,845 planet candidates for it to work through. Way back in 1989, we found the first exoplanet – HD114762 b (nicknamed Latham’s Planet, after its discoverer) – because of its great mass (10.98 Jupiter masses). That mass causes it to exert a small tug on its star due to its radial velocity, making the star “wobble”. HD114762 b is situated 128.7 light years from Earth, with a surface temperature of about 487K.

So, I thought it would be fascinating to explore our galactic neighborhood, beginning with those closest to us, working our way further into the galaxy.

Of course, as many of us know, that means we’ll start with Alpha Centauri B b:

For long-time Star Trek fans, it probably won’t come as a surprise that we found a planet around the closest star to us. They probably will be surprised by how recently that discovery happened – two years ago in 2012! Alpha Centauri B b is interesting because it’s an Earth-mass planet (1.13 Earth masses) extremely close to its star (only .0400 AU) away. That means it whips around its star (1.227 solar masses), with a very short year (3.23 days)! It makes sense that we found this planet by the same radial velocity “wobble” indicator as referenced above. Alpha Centauri B b is 4.37 light years from Earth, and is, so far, the only planet in its system.

Well, that’s it for this time! A huge part of my decision to keep the series going will be reader feedback. If it’s something you find useful, entertaining, or informative, please let me know here in the thread! If noone’s digging it but me, I’ll get that message quickly.

 

[Adam]

I'm digging it.

 

[connieflyer]

This would be an interesting topic. Can't know too much about what is around us. I am interested.

 

[agarwalro]

Re: The Galaxy is a Crowded Place – A Series

Great idea!

Ars Technica did a short writeup on the discovery of the most, potentially, Earth like exoplanet yet, Kepler-186f. http://arstechnica.com/science/2014/04/habitable-exoplanets-are-bad-news-for-humanity/

The writeup touches on the concept of the Great Filter (technological civilizations may have a tendency to fail before advancing to the point of alien contact) and Fermi Paradox (why have we not made contact with extra terrestrials even though the odds are overwhelmingly in favor of there being countless alien lifeforms). The reader comments are also with reading.

 

[connieflyer]

Very interesting reading, like the idea of the great filter. Wonder where we are, looks like on the road to extinction sometimes.

 

[Irishman]

The Galaxy is a Crowded Place – A Series (Part 2)

Welcome back. As of today, we’re up to 1,776 exoplanets, and next on our list for the series is epsilon Eridani b:

Epsilon Eridani b orbits its gas giant star about 10.44 light years from Earth, at a distance of 3.39 AUs from that host star, and has a 2,502-day year. Its surface temperature is 111.8 K. As of right now, it’s the only known planet in its system, and was discovered quite recently in 2000. It was found using the same radial velocity technique as was Alpha Centauri B b, as it was measured exerting a gravitational tug on Epsilon Eridani, a K2 V-type star.

As far as supporting life, due to its distance from its type of star (3.39 AU), it is well beyond the “Goldilocks Zone” there – which is between .65 – 1.21 AU from the star. Sadly, this means no life as we know it can exist on Epsilon Eridani b.

Thanks so much for the feedback thus far! It’s clear that you guys are enjoying it as much as I am, so I’ll soldier on with the series.

 

[rnatalli]

I can't help but think about the Fermi paradox. For those of you that are unfamiliar, the basic gist is this: Mathematically, there's likely tons of life even in our local area of the universe; however, with this in mind, we should have seen evidence of it by now.

Here's a solution to this paradox and a horrifying thought. What if we're the first? Someone has to be and if it's us, I feel bad for the poor bastards we come across.

 

[agarwalro]

I believe we are being left alone because of some intergalactic Prime Directive equivalent. Humanity is too petty and immature to deal with the implications of intelligent extraterrestrial life, because, the first thought will be, how can we weaponize this situation/technology/being... or somehow profit from it.

IMO, with habitable (in human terms) planets being an order of magnitude further out than our transmissions, it is only a matter of time, even if it is a million years from now.

 

[shadyJ]

As far as extraterrestrial life goes, since it isn't known exactly how life formed in the first place, it's difficult to determine how common it would be, although I have seen some attempts at mathematical calculations. I am not a biologist , but from what I have read, scientists know the necessary ingredients for life and likely catalyzing agents, but the odds of the spark of life occurring is still unclear. Seems like a "100 monkeys in a room banging away at typewriters, how long before one of them inadvertently writes Hamlet" type scenario.

And that is just for the mere formation of life. What about complex life? Remember single celled organisms were the only form of life for a large majority of Earth's history. It took something on the order of 2 billions years just for Prokaryotes to give rise to Eukaryotes, and a billion years after that before multicellular life rose. Life is just fine in a simpler state, and whatever has to happen to light the fuse of evolution is clearly an extremely infrequent event.

Furthermore, let's say the unlikely event of complex life has been kickstarted; well, it took Earth well over 500 million years for sentient life to form after that. From that fact I would say sentience and intelligence are definitely not an inevitability, indeed, and it looks like it is an improbability.

So what are the odds of intelligent life arising, even under ideal conditions? It isn't good. But last year there was a estimate that in the Milky Way Galaxy there are 8.8 billion planets that resemble Earth in that their orbital distance from their star doesn't prohibit life, and also have a gravitational mass which does not prohibit life. If I had to bet on it, I would bet on some life in the Milky Way, if only very simple microorganisms. The Milky Way is just one of 100 billion to perhaps 500 billion galaxies, although it is a bit larger than average, so multiply 8,800,000,000 by 100,000,000,000 to 500,000,000,000, and divide that by the average size of galaxies to get Earth-esque planets in the universe (yes, I realize it is not that simple). I am not a biologist, but I would bet that there is at least one other intelligent life form out there in the universe if I had to.

On the other hand, I would bet we will never hear from them or know of their existence, nor will they know of ours. I'm not a physicist, but it looks like the speed of light is the hard limit on how fast anything can travel. It's fast, but given that the Milky Way is over 100,000 light years in diameter, it is still very slow on a cosmic scale. The odds of any life, let alone intelligent life, being within any practical range of radio signals is infinitesimal. We are, for all practical purposes, alone in the universe.

 

[herbu]

Humanity is too...immature

Bingo!

1. How much time/effort do you expend trying to communicate with the colony of ants in your yard?
2. If you could communicate, what useful thing could you tell them?
3. How many millions of light years would you travel to do it?

We are "ants" to a civilization capable of traveling millions of light years.

 

[agarwalro]

This article talks about the most well known attempt to quantify probability of us encountering a technological lifeform, the Drake Equation and a newer proposal.

http://io9.com/what-a-brand-new-equation-reveals-about-our-odds-of-fin-531575395

 

[Chu Gai]

Bingo!

1. How much time/effort do you expend trying to communicate with the colony of ants in your yard?
2. If you could communicate, what useful thing could you tell them?
3. How many millions of light years would you travel to do it?

We are "ants" to a civilization capable of traveling millions of light years.

A civilization capable of traversing tens, thousands, or millions of light years would take far longer in terms of time to do so. Long enough to realize that whatever knowledge or information they gleaned would never make it back to where they originated from. Just as our planet can be destroyed by some unforeseen cosmic event, so can theirs. If not, assuming their original planet and inhabitants are alive, they would not even come close to resembling the explorers. Further, faced with the real limits of lifespan, I can't see anything that even resembled some sort of organic life form being able to make such a long journey. Hence, IMO, it would have to be some sort of robotic device capable of advanced intelligence and repair. Something that I think we on Earth are not that far from.

I think the primary reason a civilization would undertake such a journey would be for the purpose of looking to ensure their species' survival. Perhaps by encoding or somehow preserving what passes for their genetic makeup for such a long journey that would then be reconstituted where they landed. I also don't think that such a place would send out just one vessel. Just like us and probably more so, they have the ability to identify planets and make measurements of things like temperature and even chemical makeup of worlds. So, just like spiders do, I would think they'd send out multiple probes over many years with the hopes that one day, one of them would strike gold. And if it happen ended they'd somehow discovered ways to circumvent the speed of light barrier, well, who knows. Me, I'm putting my bets that there's some sort of life on one of Jupiter's or Saturn's moons.

 

[Chu Gai]

Fermi Paradox article.

The Fermi Paradox: Where the Hell Are the Other Earths?

 

[Irishman]

This time we’ll be taking a slight detour on our trip through the galaxy, on our search for exoplanets, in what is proving to be a very crowded galaxy. Just a week ago, I would have been making a very different kind of post in my series to highlight the exoplanets that are the closest to our star. But due to the rapid advance of science, a new discovery was announced just a few days ago that has changed that.

What is it?

The answer is Kapteyn b. Kapteyn’s star is named – as is tradition – after its discover, the Dutch astronomer Jacobus Kapteyn. There are several qualities about Kapteyn b that make it special: 1) Its proximity to Earth, which is 12.75 light years, and 2) Its age, which is roughly 11 billion years old. To put it into perspective, the Earth is about 5 billion years old. Life on Kapteyn b has had twice as long to evolve, 3) Its mass is 4.8 Earth masses, which puts it into the category of super-earths, 4) Its orbit around its M1.0 type star is 48.62 days, which puts it within its Goldilocks zone of .07-.15 AUs. This delicate combination of qualities make Kapteyn b a place which should keep our attention for a long time to come.

Kapteyn b isn’t alone in its system. We have - so far - found a second planet, called Kapteyn c, another super earth that is 7.0 Earth masses, orbits further away – 121 days - from its host star, and thus, too far outside of its habitable zone to support life as we know it.

Both Kapteyn b and Kapteyn c were found in 2014 using the tried and true radial velocity method.

Here is a good starter link to more of the methodology of how we learned what we know about these planets. Oldest Known Potentially Habitable Exoplanet Found - Planetary Habitability Laboratory @ UPR Arecibo

 

[GO-NAD!]

What a coincidence! I just watched this program yesterday: Planet Hunters - The Nature of Things

It outlines the search for exoplanets, from the moment technology became sufficiently advanced to enable such a search, up to present day efforts. And, it explains the methodology used to determine a planet's existence, as well as its characteristics. Unfortunately, I don't think it can be viewed outside Canada.

 

[Adam]

What a coincidence!

No kidding! Hardly anybody is talking about exoplanets these days.

 

[3db]

I believe we are being left alone because of some intergalactic Prime Directive equivalent. Humanity is too petty and immature to deal with the implications of intelligent extraterrestrial life, because, the first thought will be, how can we weaponize this situation/technology/being... or somehow profit from it.

I agree....Humanity as a whole is selfish, cruel, and opportunistic.