aesmael | Entries tagged with galaxies

Originally published at a denizen's entertainment. You can comment here or there.

Last week seems to have been a good week for news in astronomy. At the least of the sorts that capture my especial interest.

From Universe Today, Spot Discovered On Haumea Rich With Organics And Minerals.

Haumea, one of those planets called dwarfs, is notable for its extremely rapid rotation (a bit less than four hours) distorting its shape well out of spherical and its pair of moons (and the origin of those moons being a probable collision early in Haumea's history which stripped much of its mantle and originated the Haumea collision family). I was thrilled to see such a headline, although on further reading of the article it seems a touch premature:

Possible interpretations of the changes in the light curve are that the spot is richer in minerals and organic compounds, or that it contains a higher fraction of crystalline ice.

So although it appears there is a dark patch on Haumea's surface, we won't know its composition until next year at the earliest. Still, I'm excited to learn just about any new details about these worlds.

Via the Extrasolar Planets Encyclopedia (currently 374 planets and counting), a preprint of a paper submitted to The Astrophysical Journal: The Formation Mechanics of Gas Giants on Wide Orbits.

Presently there are two major theories concerning the formation of giant planets. The core accretion model holds that if a planetesimal can accumulate at least ten Earth masses before the gas of the surrounding protostellar disk dissipates, it will be able to rapidly accumulate a massive envelope of gas. Meanwhile the disk instability model proposes giant planets form when part of the disk becomes unstable and collapses in on itself like a version in miniature of how stars form from giant molecular clouds.

For a while now the core accretion model appears to have prevailed, I think largely because the two models produce different sorts of planets with only a bit of overlap, and most of the planets we have been finding so far suit the core accretion model far better. That is, planets with up to a few times the mass of Jupiter, on orbits less than 10 - 20 AU (Astronomical Units) from their host star.

This paper reminds that there are now planets being found which the disk instability model explains far better than the alternatives - more massive planets approaching the realm of brown dwarves, on orbits too distant for core accretion to have produced them in situ, with orbital dynamics suggesting they were unlikely to have arrived there by scattering from interactions with other planets.

After reading it, I would not be surprised of Fomalhaut b did turn out to originate from core accretion and scattering, but I think they are probably right about the planets of HR 8799 and that there are many more such systems to be found. Would be very interested to learn if there are inner planets to these systems yet undiscovered, and what happens when both planetary formation modes are at work in the same system.

Another quick bit from Universe Today: Smallest Exoplanet Yet Has Rocky Surface. CoRoT-7 b may not turn out to be the smallest planet orbiting an actively fusing star yet discovered, but it is the one with the lowest mass we are currently sure of. The article is definitely worth reading, as some of the details about that planet are amazing.

A picture from Astronomy Picture of the Day, the Andromeda galaxy in UV. Was thrilled to note that in the mouseover comparison, the correlation of UV areas with bright blue starforming areas.

From The Planetary Society, "Richard Kowalski is the first person in history to possess a piece of an object that he discovered in space", an asteroid detected in space and tracked to its impact in Sudan last year. I don't know how I managed not to hear of this at the time it happened, but here is an account from shortly after it happened.

Current Mood: curious

Google Reader Shared Items

Thank You Thursdays: Your (Notice I Didn't Say Female) Brain [via gentle_gamer. Comments to the post made me warier of this video. Did she have that brain cut in half to illustrate her point? Am pretty sure most brains I have seen are in a single piece unless cut. Much of her described experience of having a stroke is not unfamiliar to me, if to a greater degree. Not, I stress, identical, but apparently similar to something which can be accessible to me. If I were to release certain brakes, if I could remember how. I have a lot of hostility to the frame in which she presents her thesis, despite finding much recognition or even agreement in the details.

I dislike the way people jumped on ropty's comment ("Non-gendered? Dividing the world into two parts, one is linear, unemotional, calculating and the other about feeling, emotions, timeless oneness. Gee, that sounds rather gendered to me.") because this is a thing which is done, this is a way in which brain functioning is presented and those traits are very gendered in this society. Also that my readings of other writings on neurobiology suggest this is a highly oversimplified perspective on human brain hemisphere functioning, though as this was a talk for a lay audience that may have been deliberate. And it still seems to me her described experiences are very 'on point' even if I am not so fond of her presentation of them.

I wonder if making such experience accessible at will would have the effect on the world Dr Taylor describes.]
Video: Blaser tournament unwisely fits Japanese robots with lasers -- PEW PEW [via soltice. If we intercut this with some footage of people we could make a movie of it.]
New Hubble Images Reveal Plethora of Interacting Galaxies [via soltice. Pretty!]
Young feminists just want to "go wild and pole dance" [via gentle_gamer.]
How To Sing Like A Planet [via gentle_gamer. Wherever there be medium and motion, music. The article makes me angry, with it's talk of 'merely' as if scientific explanation of such magnificent happenings cannot be also magnificent, wondrous or beautiful themselves. I lost a lot of esteem for the writer's prior musings when I read that part.]
Atheism is a condom for your mind [via soltice. The part I disagree with is the phrasing suggestive that removing religious belief is a part and precursor to mental hygiene and health -- I would place taking care of the mind first, and if that leads to the removal of religion then so be it. Someone eventually said so too.]
Equality Through Intimidation? The Houston HRC Dinner Protest [via gentle_gamer.]
Comical Surroundings [via soltice. This is interesting but I think I would not like my furniture to be displaying always the same images and words. After so many repetitions reading, wearying.]
Modular, shape-shifting robots get right back up to creep you out [via soltice. Shiny! Still a ways to go before they are as capable as the version seen in Terminator 2 though.]
Australia to Remove Antigay Discrimination From 100 Laws [via soltice. An improvement, but not enough.]
Maintaining Moore's law with new memristor circuits [via soltice. Fascinating (a thing said when {in this case} interested but uneducated in a subject).]

Scienceblogs

Vaccination doesn't cause autism volume what-are-we-up-to-now? [And yet we see how well the continued lack of evidence substantiating a connection is received. *sigh*]

Current Mood: sleepy

Although the galaxies depicted in Stargate: SG1 and Stargate: Atlantis exhibit a remarkable frequency of terrestrial, habitable planets, it is also notable that such worlds in each galaxy exhibit generally a distinct, consistent terrain.

Specifically, nearly every world on each show is a forest, and the same forest within the show, but a different one between shows. Clearly significant - this researcher thinks the Atlantis forest looks greener and has higher resolution leaves than the SG1 forest, and possibly indicative of seeding by a hitherto unknown precursor species separate to the Ancients, or possibly merely a shift in Ancient aesthetic.

Current Mood: silly
Current Music: Stargate: Atlantis

My oh my, what a thing to find on one's desktop!

A pair of galaxies spied amid the twirl of passionate embrace, drawing ever closer in their romantic dance. Heedless, they cast off streamers of dust and gas, molten stellar droplets flung free and with every pass passing closer they press together, diving into the substance of the other, igniting in their mutual compression fires which blaze across the cosmos for all to see and do not care for they are beautiful.

Current Mood: ecstatic
Current Location: streamside meadow, writing book, windswept hair, distant eyes
Current Music: Dragonstea Din Tei - O-Zone/All My Loving - Jim Sturgess [Across the Universe soundtrack]

    A thought, earlier in the reading than the writing. I have noticed a very strong tendency for readers to only comment on a single aspect of a blog post. Often, indeed, people will remark on the same thing rather than each picking a different topic to follow. I could not say if this is an artefact of following after the first to comment or of a particular part of the post finding better resonance with the readers in general, or to what degree it might be a combination of those (or other?) factors.
    It does tend to make me inclined to separate thoughts into posts rather than paragraphs to better spark discussion (although I also am wary of what I have seen called 'spamming people's friends lists'). Is that bad or good? It is a change in style from my previous unexamined preference. An adaptation to the medium which maybe better accomplishes goals (provoking discussion, sharing ideas, providing learning/enlightenment opportunities for myself), so it may well be good. If I could someday say the state of the world has been improved I might even call it Good but that is rather unrealistic.
    It is a change and on that ground I am inclined to dislike it. Is this because I grew up reading of older modes of discussion and hoped someday to participate in them myself? I think so. I am disappointed but, to refuse to take into account the fact that the world* is changing (I cannot appreciate how much) would be counter-productive. Nor would I know how. Do I write a letter to my friends?
    That blog posts slip away so swiftly is an annoyance. Oh, they are saved and still accessible later but they only hold attention very, very transiently. This might be more a matter of substance than medium. Sometimes when I have written something I am especially pleased with I am tempted to withhold from further posting for a number of days so that it remains more visible, even though anyone who reads what I have to say is using LiveJournal and the flow of their river is little affected by what I do. Should put in a feature request to be able to tag posts into streams of varying priority, then the daily grind can flow on and disappear while topics for discussion remain visible until displaced by more discussion.
    These thoughts are incomplete.

Amusement: Blogging software in a browser with built-in spell-check ability does not recognise 'blog' as a legitimate word.
Further amusement: I suspect I ironically mangled that laughing sentence.

Ami Angelwings Heavenly Comic Rants

Negativity hurts Ami :( [Ami is right. Nominal equality doesn't mean everything is peachy keen now, there is still time needed for (hopefully) social attitudes overall to improve. And spreading negativity, pulling other people down does not seem very helpful to me - I rather thought the idea was to pull people up, so to speak, although if a person is behaving badly/advocating for a harmful position I do thing they should be called on it somehow. Sadly, my opinion is that a large part of this is human nature and not subject to change in the immediate future.]

Ami Angelwings' Heavenly Comic Reviews

Small update :O [*sigh* At least I know where not to spend money]

Astronomy Picture of the Day

Pantheon Earth and Moon [It took me a while to see this as an image of something real.]
3D Face on Mars [I need to make a pair of those red/blue glasses]
Smooth Sections of Asteroid Itokawa [The rubble-pile asteroid collision simulation shown in this link bears passing resemblance to simulations of colliding galaxies. That site looks very interesting. Must revisit. I think this particular APOD is a repeat though, hasn't taken account of the CIA World Factbook move. I am excited to learn what we might discover when Hyabusa returns - we have never brought a sample of an asteroid back to Earth for study before (although there have been some self-deliveries). Note to self: Find out more about these low gravity 'space hopper' probes. Amusement: The Wikipedia article on the 'Brazil Nut Effect' has been edited to mention this picture, since that kind of sorting by size has been proposed as a mechanism to explain the lack of visible craters on the asteroid. I suppose what we need to do now is send another probe to probe its interior with radar.]
A Supply Ship Approaches the Space Station [Just as it says. The blog of one of the astronauts being delivered is here, too bad I did not know about it while it was being written. Photo added to desktop slideshow.]
The Sun in Three Dimensions [Hey! You're missing one!]
Carina Nebula Panorama from Hubble [Eta Carinae is one of my favourite possibly already dead stars. As the article said it did fade dramatically in the 1830s (and if memory serves, had first brightened dramatically). Eta Carinae is one of the most luminous, massive stars we know of. Possibly it is even larger than our theories allow for a star to be - but it is not the most stable of stars, already having blown off an amount of mass equivalent to that of our Sun many times over and producing frequent, enormous eruptions. It is not expected to last long for a star. And it might be a binary! I remember reading a paper in the university library suggesting that a regular variation in X-ray output may be caused by a companion star with a ~5 year orbit, although the amount of dust and gas Eta is giving off, I think, make it impossible for us to observe directly. Eta Carinae's companion might be much smaller than Eta but still be a rare giant among stars - Eta Carinae is in a class of perhaps a dozen out of ~200 million stars in this galaxy. So naturally this is another desktop picture]
Gliese 581 and the Habitable Zone [Yup, they are finally finding these worlds. There will be many, many more to come.]
M81 in Ursa Major [Pretty!]
Young Moon and Sister Stars [I wanted to see this but kept forgetting to look]

Ballastexistenz

And still no blog carnival because... []

But Enough About Me!

Further Ruminations on Girls, Coming of Age, and the Hero's Journey [The often important reminder that, in valuing difference, one must be careful not to devalue the ordinary ('sneering at "the mundanes"'). Read the comments. I want to keep thinking about the topics raised here and they do plenty to keep it going.]
"They didn't want the violence to be real or the truths to be inconvenient." [Refers to this post by Gwyneth Jones|Bold As Love. New word for me: traduce. I am tempted to step away and say I do not have the education or insight to respond to this. Yet, if I do, how will I ever acquire them? I believe I must attempt to engage in order to learn. So I will ponder the first question coming to mind: what else could be considered a success? Is there any other outcome that might be considered a victory for more than immediate visceral gratification? But those questions fail to address the substance of the post. More understanding required. The word grok springs ironically to mind (I get to use that word once more in this post before you are allowed to complain.]

Calvin and Hobbes

2007-04-28 [*smiles* Not that easy]

Devil's Panties

2007-04-28 [:-/ Sure, she's sitting on the mallet, but what is holding the mallet up?]

Dilbert

2007-04-28 [meh]

Order of the Stick

445: A Song for the Departed [I had been trying to wait and see how sad I should be, before Rich Burlew went and had Elan show us.]

Peanuts

2007-04-28 [also meh]

"I hope you see the sun, someday in the darkness"

*The world is humans and their doings, their society? There is more than that, oh yes, but we are all-consuming to ourselves. And this is where we live.

Phil Plait introduces ‘Q & BA', in which he takes questions from readers and produces a video answering some (this week, galaxies). Go check it out! To send in questions of your own, see here.

Phil Plait has a post up about NGC 1316, a galaxy careless enough to let four of its stars go supernova in the space of 26 years, two in the past six months. For comparison the average is one per century (Without more information I would assume this is referring to more massive galaxies with active star formation like our own).

I could go on more, I suppose, but pretty much everything is covered at Bad Astronomy. Well, I can add that a galaxy is a very big place and these two supernovae certainly occurred thousands of light years distant from each other. They would have exploded centuries, perhaps millenia apart in time and it is only coincidence we see them at nearly the same time (same for the other two, too).

Current Mood: excited
Current Music: The Steward of Gondor - Howard Shore & Billy Boyd

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aesmael

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Astronomy News
(no subject)
Geography and ecology across galaxies: a comparison
Galactic sex?
Connexions
Got Any Astronomical Questions?
Okay Galaxy, You Have My Attention

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