''Our solar system is not as unique as we might have thought.''

[Octafish]

That kind of talk boggled a lot of minds a generation ago.



New Instrument Reveals Recipe for Other Earths

Harvard-Smithsonian Center for Astrophysics
Release No.: 2015-03
For Release: Monday, January 5, 2015 - 1:15pm

Cambridge, MA - How do you make an Earth-like planet? The "test kitchen" of Earth has given us a detailed recipe, but it wasn't clear whether other planetary systems would follow the same formula. Now, astronomers have found evidence that the recipe for Earth also applies to terrestrial exoplanets orbiting distant stars.

"Our solar system is not as unique as we might have thought," says lead author Courtney Dressing of the Harvard-Smithsonian Center for Astrophysics (CfA). "It looks like rocky exoplanets use the same basic ingredients."

Dressing presented the research today in a press conference at a meeting of the American Astronomical Society.

The key to the discovery was the HARPS-North instrument on the 3.6-meter Telescopio Nazionale Galileo in the Canary Islands. (HARPS stands for High-Accuracy Radial velocity Planet Searcher.) It is designed to accurately measure the masses of small, Earth-sized worlds. Those measurements are crucial to determine densities and therefore compositions.

"Our strategy for using HARPS-North over the past year has been to focus on planets less than two times the diameter of Earth and to study a few planets really well," explains Harvard astronomer David Charbonneau (CfA), who currently heads up the HARPS-North Science Team.

Most recently the team targeted Kepler-93b, a planet 1.5 times the size of Earth in a tight, 4.7-day orbit around its star. The mass and composition of this world were uncertain. HARPS-North nailed the mass at 4.02 times Earth, meaning that the planet has a rocky composition.

The researchers then compared all ten known exoplanets with a diameter less than 2.7 times Earth's that had accurately measured masses. They found that the five planets with diameters smaller than 1.6 times Earth showed a tight relationship between mass and size. Moreover, Venus and Earth fit onto the same line, suggesting that all these worlds have similar rock-iron compositions.

As for the larger and more massive exoplanets, their densities proved to be significantly lower, meaning that they include a large fraction of water or other volatiles, hydrogen and/or helium. They also showed more diverse compositions rather than fitting into a single group like the smaller terrestrial worlds.

The team also noted that not all planets less than six times the mass of Earth are rocky. Some low-mass worlds with very low densities are known (such as the planets in the Kepler-11 system). But for typical close-in small planets, the chances are high that they share an Earth-like composition.

"To find a truly Earth-like world, we should focus on planets less than 1.6 times the size of Earth, because those are the rocky worlds," recommends Dressing.

The paper presenting this work has been accepted for publication in The Astrophysical Journal.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

SOURCE: http://www.cfa.harvard.edu/news/2015-03

Additional info: http://www.dailygalaxy.com/my_weblog/2015/01/our-solar-system-not-as-unique-as-we-thought-center-for-astrophysics.html

The image above shows the "Pillars of Creation," a star forming region in our galaxy first photographed in startling detail by the Hubble Space Telescope in 1995.

[Mnemosyne]

1. That photo always takes my breath away.

[Octafish]

2. Me, too, Mnemosyne! Hubble team has made it better...

ETA: Amazing, the things we know in 2015.



Hubble Goes High Def to Revisit the Iconic 'Pillars of Creation'

News Release Number: STScI-2015-01

JANUARY 5, 2015: Although NASA's Hubble Space Telescope has taken many breathtaking images of the universe, one snapshot stands out from the rest: the iconic view of the so-called "Pillars of Creation." The jaw-dropping photo, taken in 1995, revealed never-before-seen details of three giant columns of cold gas bathed in the scorching ultraviolet light from a cluster of young, massive stars in a small region of the Eagle Nebula, or M16.

Though such butte-like features are common in star-forming regions, the M16 structures are by far the most photogenic and evocative. The Hubble image is so popular that it has appeared in movies and television shows, on tee-shirts and pillows, and even on a postage stamp. And now, in celebration of its 25th anniversary, Hubble has revisited the famous pillars, providing astronomers with a sharper and wider view, shown in the right-hand image. For comparison, the original 1995 Hubble image of the gaseous towers appears in the left-hand view. Streamers of gas can be seen bleeding off pillars as the intense radiation heats and evaporates it into space. Stars are being born deep inside the pillars.

SOURCE: http://hubblesite.org/newscenter/archive/releases/2015/01

[Mnemosyne]

22. Awestruck is another good description! nt

[kentauros]

14. Yesterday's "Astronomy Picture of the Day"

took my breath away and I'd call it competition for the pillars-image

100 Million Stars in the Andromeda Galaxy

Image Credit: NASA, ESA, J. Dalcanton, B. F. Williams, L. C. Johnson (U. Washington), PHAT team, R. Gendler

Explanation: What stars compose the Andromeda galaxy? To better understand, a group of researchers studied the nearby spiral by composing the largest image ever taken with the Hubble Space Telescope. The result, called the Panchromatic Hubble Andromeda Treasury (PHAT), involved thousands of observations, hundreds of fields, spanned about a third of the galaxy, and resolved over 100 million stars. In the featured composite image, the central part of the galaxy is seen on the far left, while a blue spiral arm is prominent on the right. The brightest stars, scattered over the frame, are actually Milky Way foreground stars. The PHAT data is being analyzed to better understand where and how stars have formed in M31 in contrast to our Milky Way Galaxy, and to identify and characterize Andromeda's stellar clusters and obscuring dust.

It's a huge image and probably best viewed on the APOD site

[Mnemosyne]

23. It makes me feel very minute and extremely vast in the same moment. What is an APOD

site, btw?

[kentauros]

31. APOD means "Astronomy Picture of the Day"

and is a NASA site. Here's today's APOD, and link
(I love the color of this one, too.)

Stars and Dust in Corona Australis
Image Credit & Copyright: CHART32 Team, Processing - Johannes Schedler

Explanation: Cosmic dust clouds and young, energetic stars inhabit this telescopic vista, less than 500 light-years away toward the northern boundary of Corona Australis, the Southern Crown. The dust clouds effectively block light from more distant background stars in the Milky Way. But the striking complex of reflection nebulae cataloged as NGC 6726, 6727, and IC 4812 produce a characteristic blue color as light from the region's young hot stars is reflected by the cosmic dust. The dust also obscures from view stars still in the process of formation. At the left, smaller yellowish nebula NGC 6729 bends around young variable star R Coronae Australis. Just below it, glowing arcs and loops shocked by outflows from embedded newborn stars are identified as Herbig-Haro objects. On the sky this field of view spans about 1 degree. That corresponds to almost 9 light-years at the estimated distance of the nearby star forming region.

If you click on the Archive link at the bottom of each page, you'll get a page listing all of the previous APODs. There are some fine terrestrial photographs there as well

[chrisa]

18. Even more interesting is that the pillars might not even exist anymore.

Some think that they were destroyed by a super nova 6000 years ago, and we'll be able to see this happen when the light reaches us in 1000 years.

[Mnemosyne]

24. Damn, don't think I'll last long enough to see that, but am willing to try.

[chrisa]

25. You could always freeze yourself like Fry on Futurama.

[kentauros]

32. Or just your head!

Albert Arnold Gore, Jr.

[SheilaT]

3. My oldest son is finishing his bachelor's in physics, and

wants to go on and get a PhD in astrophysics. So he is my go-to guy about things like this. If I understand what that son has told me, at the present we can't really detect planets as small as our Earth, but there's good reason to think they're out there. He also tells me that (at least so far as he understands it) they can't yet detect things like an atmosphere around a planet that is otherwise earth-like.

As an inveterate reader of science fiction, when I read about a rocky planet with a mass four times that of Earth, I'm thinking the gravity of that planet will be a lot stronger -- four times our gravity? Which means that not only could we not really go visit that planet very safely, or at least not stay on the surface very long, but the evolution of plants and animals would be shaped by that stronger gravity.

The life that is out there -- and almost definitely there is life out there -- is going to be so very different from ours that it takes my breath away. It's just a shame that the distances are so great that we probably won't be able to visit. Certainly not in my lifetime, and perhaps not ever.

[navarth]

4. Let's hope our species survives long enough to explore.

Science Fiction aficionado of long standing here. I wish I could live long enough to see what the future will bring. Will we make it to the stars? Seems to me the key is that we wise up enough to not make everything extinct.

[AngryDem001]

5. And we have to stop sucking at the teat of WAR.

I really do think that hope for space exploration lies in companies like Space X.

NASA is being held back by Repukes who choose religion over science.

[zeemike]

6. I have never understood the thinking that we are the only one.

But that idea has clung on despite the mathematics of it...billions of stars billions of galaxies and infinite time...it had to have happened more than once.
And now we know there are other planets around stars and perhaps most stars have them.

I seems more like a defense of ego to me...we must be special.

[hedda_foil]

11. Me either ... from a very early age.

I remember thinking that the idea was the one and only planet, or even the only place where life existed was ridiculously simplistic in elementary school in the fifties.

[edhopper]

27. Life could be widespread

intelligent life, at least technology users, seem to be rare.

[zeemike]

30. Well they are rare on this earth.

But as we know, life on this planet is everywhere...in the deepest depths of the sea to the top of mountains and so diverse it boggles the mind.
And so the odds are that we are an average planet and in the universe there are probably millions that have what we have and more.

[edhopper]

33. I agree that based on what we observe here

life can be prevalent.

But even here intelligent life is very recent and very random. It needed lots of enviormental disasters to get going.

And even other intelligent life might not use technology.

Based on the fact that we haven't caught any radio signals I think the very narrow category of technologically advanced intelligent life is rare.

[zeemike]

36. Well that too can be debated.

We really don't know as much as we think we do about life on this earth...there could have been many that used tools and technology that became extinct for one reason or the other...we assume we were the only ones because we know so little about history beyond what is written about.
And Radio signals are old technology that could have been abandon as communication millions of years ago like we abandoned the telegraph when there were better ways.
There could be a planet right next to us that communicated with fiber optics or light and we would never know it...and radio is by no means a necessary step in development of higher civilizations.

So I don't assume anything about the universe...not with the little knowledge we have to work with.

[edhopper]

37. When I say radio

I mean the radio-electronic spectrum.

I know it can be debated. It's just my educated guess based on the some of the premisses I mentioned.
We have no information on life outside of Earth, so we can only speculate.
My opinion is no better than another well-informed one.

I also think that there can be plenty of intelligent life that just doesn't use technology, so finding them would be near impossible.

[zeemike]

38. I like to speculate...I think there are things to be learned by it.

But even hear on earth the radio spectrum is obsoleate...we are communicating right now on a beam of light, mad possible by the microchip and digital techknology...and it is undetectable in the radio spectrum.
And you think that in the space of 100 years we went from AM radio in the kilohertz to digital that is in the giga Hertz in frequency and we have not reached the limit yet.
Think of what a thousand years could bring...if we don't exterminate ourselves that is.

But the universe is a vast mystery and we have only scratched the surface in our understanding.

[edhopper]

41. Good points

[G_j]

7. great article

thanks Octafish!

[malokvale77]

8. Thank you Octafish

I love your posts. Always informative.

[Zorra]

9. We simply can't be the only life form in the universe that is capable of deliberately

destroying a planet.

[dissentient]

10. Yep, and my opinion is the universe is full of other intelligent life, and probably

most of 'em are much more advanced than we are. They may even know about us too.

[Jim Lane]

12. That still leaves us with the Fermi Paradox: "Where is everybody?"

It seems plausible that there should be many other intelligent species just in this galaxy, but we haven't detected any evidence of their existence (radio waves being a more plausible candidate than flying saucer visits).

The Wikipedia article begins: "The Fermi paradox (or Fermi's paradox) is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilization and humanity's lack of contact with, or evidence for, such civilizations."

Fermi raised the point in 1950 and it's still a good questin.

[sammythecat]

15. I think Fermi might have been joking

because, if he was serious, it seems like a dumb question to me. I say that in all humility. Fermi was a genius. I'm just a regular average guy. An armchair astronomer with absolutely no expertise or training in the field of astrophysics.

Any extrosolar planets in the galaxy are light years away. 5-50,000 light years away. We've been searching within a narrow band of the spectrum for what, 50 years or so. That's a ridiculously small area and time frame to come to the conclusion of "nope, nobody there". Plus, these "people" could easily be millions of years ahead of us and the idea of them searching the heavens listening for radio signals might seem as quaint to them as looking for smoke signals would be to us. And radio waves do dissipate with distance, even in space. ETs on the other side of the galaxy won't be able to pick up original broadcasts of "I Love Lucy".

The galaxy could be teeming with life looking for other life but the likelihood of us detecting others, or others detecting us, with radio signals within the past 50 years, is exceedingly small.

[Jim Lane]

16. Fermi was serious, although it wasn't a subject of any formal research of his.

The whole thing grew out of a lunchtime discussion among several physicists, including Fermi and Herbert York. According to the Wikipedia article:

York writes that Enrico Fermi "followed up with a series of calculations on the probability of earth-like planets, the probability of life given an earth, the probability of humans given life, the likely rise and duration of high technology, and so on. He concluded on the basis of such calculations that we ought to have been visited long ago and many times over."

That's why the question is now known under that name, even though others have done much more work on it than Fermi did.

What you suggest in explanation has been argued by people who do have "expertise or training in the field of astrophysics." There are many other possibilities, too.

[sammythecat]

17. If life is common throughout the universe, and if,

and this is a very big if, they have figured out practical means of interstellar and even intergalactic travel, then I'd have little doubt that we might "have been visited long ago and many times over." That we would know nothing of these visits doesn't surprise me at all. It would, however, surprise me if they decided to communicate with us. They would be ridiculously more advanced than us and could learn all they wanted about us by observation. There'd be a lot to learn about us maybe, but little or nothing to learn from us. They'd certainly consider us primitive and likely even dangerous.

I know Fermi said this long before we found out how apparently commonplace planets are. And I know that even with a zillion planets, it's a very extreme long shot for any given planet to have bacteria let alone any kind of intelligent life. But those two facts and the fact there is no evidence of any present or prior visits do not seem (to me anyway) reason enough to conclude it never happened and likely never will.

My own thoughts on this are that I think it more likely than not there is other intelligent life in the universe and I used to think it was likely we'd been visited or observed. I now think the visit/observed part is unlikely. Other than maybe making an extraordinary effort to visit a couple of the nearest stars, I fear interstellar travel might be forever out of our reach. Hell, I don't think it's a safe bet this planet will even have a functioning modern civilization a thousand years from now.

[chrisa]

35. Part of the problem is that, overall, humans aren't overly bright.

An animal more intelligent than us would have abandoned war long ago because it's the most logical and efficient thing to do. They would also work together rather than trying to constantly hurt each other, and not focus on shortsighted things like riches, status, and power.

Without any of the stupid things we do, humanity would be at least centuries more advanced than it is now.

[dissentient]

19. Maybe they don't want to officially make contact with us

maybe in their eyes, we are still on the level of Neanderthals, and they will only be interested in contacting us when we advance much more than we are currently at.

That is, assuming we don't destroy ourselves first.

[sammythecat]

21. My thoughts as well,

and if they are, or have been, here, then I'm much more inclined to think there is a LOT of intelligent life out there and much of it far more interesting than us. Just the fact they are capable of interstellar travel tells me they are way, way more advanced we are. What in the world would we have to teach them? I'm guessing, but I don't think we've had deodorant for much more than a hundred years.

Plus, not only are we a danger to ourselves as you said, but nearly every other living creature on this planet as well. If I was them, I'd look but I wouldn't touch.

[chrisa]

34. It's possible that our planet is so ordinary that no one has bothered to visit it.

Our usage of radio waves and technology may also be so laughably primitive to alien life that they see us like we see ants.

Also, we haven't been able to send radio waves out for a long time in the grand scheme of things (a sliver of a sliver in human history, let alone the history of the universe) that it's possible that no one contacted us yet. The universe is massive in scale - mind-meltingly so. Maybe there are more interesting civilizations out there, and we just aren't worth visiting.

Also, given human behavior, maybe they think we're obnoxious, psychotic apes that are looking to kill everything in sight. I wouldn't want to visit us either.

[sammythecat]

13. Something to give one perspective to what we're seeing there,

or maybe take away all perspective and render it totally incomprehensible:

That "pillar" on the left is 4 light years long from bottom to top. That's 23,520,000,000,000 miles. 23.5 quadrillion miles. A spaceship traveling at 1 million mph would take 2,685 years to travel its length!

I'd love to know how far away you'd be to see a view like that from the bridge of the starship Enterprise.

As far as I know, I don't think there is any serious research being done as to how to practically travel such distances. I don't think anyone even has an idea of how, or what direction to take, in order to figure out that problem. The possibility, indeed even the probability, is that we will never be able to physically explore things like this. Look, but never touch.

[Avalux]

20. Well DUH!

Human being are so egocentric, at one time we thought the earth was flat, and the center of everything we could see in the sky, and yes, that our solar system is somehow superior or different from all other possible solar systems out there.

The universe - or multiverse - is vast and much of it beyond explanation. Yet, the ball of yarn is being unraveled, leading us to discover that other intelligent life forms exist.

That is, if we don't destroy ourselves first.

[nichomachus]

26. Let's do the math

There are 170 billion solar systems just in our galaxy and 170 billion galaxies in the observable universe. I'm guessing there's going to be more than a few just like ours.

[immoderate]

28. I don't think a civilization can survive capitalism.

I think it's a natural barrier.

--imm

[dembotoz]

29. but i am still fond of this one

no plans to move

[True Blue Door]

39. The ingredients may be standard, but the permutations are likely vast.

The biggest variable in Earth-mass planets would be geology - plate tectonics vs. catastrophic volcanism vs. dead interior. That determines atmospheric chemistry, which can radically alter atmospheric temperature relative to the same amount of sunlight. Earth with a different gas profile could be either like Mars or a milder version of Venus - or things entirely out of our experience, like waterworlds that look like blank balls of white water cloud.

[Judi Lynn]

40. Thank you! Rec. n/t

[greytdemocrat]

42. Thanks Octafish

That's a great photo, love it.