A Close Encounter Of The Stellar Kind 19
Beowulf_Boy writes "Acording to the APOD on July 7th, The star in this image known as Gliese (Gl) 710 (currently 63 lightyears away), will be only 1 Lightyear from Sol in 1.5 million years. Currently, it is much to faint to be seen by the naked eye, but, in 1,502,000 A.D. it will be at .6 magnitude, rivaling the current bright star of Antares. Although Gliese 710 will not apparently present any major dangers, it could possibly scatter debris out of the Oort cloud, cause many more comets and meteors than usual.
This future stellar encounter was discovered by researchers Joan Garcia-Sanchez and Robert Preston (JPL), and collaborators while studying stars in the solar neighborhood using data from the Hipparcos Astrometry Satellite."
This isn't hazard-detection work. (Score:2)
The purpose of this research was almost certainly not to find threats to Earth - it was to get a better map of dim stars in our area, which lets us check some of our models of star formation and celestial dynamics in our area of the galaxy.
It also provides another data point for planetary system models (by giving us a better idea of how frequent close stellar encounters are, which certainly affect sytem formation), and (if they're finding stars in addition to just measuring their courses) a better estimate for the amount of normal matter in the universe (there has been debate over how much of it is bound up in dim stars and sub-stellar objects like brown dwarfs).
What most likely happened here is someone noticed that this star in their survey would come close to earth, and said "hey, neat, free publicity for our project".
Most astronomy is pure research - there won't *be* an application for most of it.
Not "Return" (Score:1)
What is "shockingly similar" between a hypothesized orbiting star and one which happens to pass nearby?
Re:Accuracy? (Score:2)
Re:Return of the Death Star (Score:2)
Behold the start of a glorious day:
Divine Retribution is on its long way.
Through the deep void it never does stray:
Divine Retribution is on its long way.
It does not stray, but it tarries a bit --
Divine Retribution is a long way away --
And our Lord God shall throw a great fit
On Divine Retribution's late Day.
It takes its time, there is no big rush,
On this Divine Retribution's late way.
Penitents desperate, through the church doors do push,
In hopes Retribution to sway.
Yet in some dark, foul smelling quarter,
The Fiend of Heaven doth say,
"What is the fuss? What is the matter?
Divine Retribution's a million years away!
"And if this dread threat truly doth come,
As Divine Retribution well may,
Profit! Loss! Check ye the sum!
And Divine Retribution thus weigh!
"The punishment fits, and would deter --
Let Divine Retribution have its say --
And were I immortal, true, I would prefer
To avoid Retribution's dread way.
"But a million years is a long time ahead,
And I too have something to say:
Most, in a hundred year's time, will already be dead
And for Divine Retribution can't stay.
"And fear not some Divine resurrection:
Such is not Divine Retribution's Good way,
But sleep safe in sweet Death's good protection,
And let Divine Retribution have its day.
"For what sort of Divine Unknowable
Would make this Divine Retribution's way
Such to steal from the earth, as if with a shovel,
Just to punish on Divine Retribution's dark day?
"T'would needs be a Divine most Retributive
To send such Retribution this way,
And to such blasphemy is Nature prohibitive
And would make Divine Retribution thus stray."
Re:Return of the Death Star (Score:1)
This thing is 65 light-years away. Now, I haven't run the numbers through Kepler's Third Law, but my intuition is that anything that far out, and in an actual orbit, would have an orbital period in the billions of years-plus area. Not a mere 30 million years or so.
The space.com page you linked to contains this diagram [space.com] which shows the predicted orbital range for Nemesis to be in the 1- to 3-lightyear separation range. This seems plausible, and I'll bet the astronomers who came up with it have run the numbers through the Third Law and liked what they saw.
Even with a highly eliptical orbit, it doesn't gel that the star would be 65 light-years away and due to arrive in a mere 1.5 million years (out of a 30 year cycle.) That would mean that it's been swinging around for a long while and is "almost here." How far away would it have to swing, 700 light-years? With that sort of range, we'd never have a regular period for it of 30 million years. Other stars would capture it, or otherwise screw up its orbit, as it swung by.
So, intruiging, but I believe, wrong.
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Whoa Dude! (Score:1)
get ready to watch it... (Score:2)
So what time does it start?
Return of the Dread Error is more like it... (Score:2)
And those are just a couple of the most glaring errors -- his short page is littered with them. There ain't no physics there.
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Gliesemageddon (Score:1)
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"Passion Rules Reason." Blood of the Fold
Re:Correction to the correction (Score:1)
Re:Accuracy? (Score:1)
Stars in the solar neighborhood are gravitationally isolated, because of the great distances between them (even one light year is a *huge* distance, from a gravitational point of view). So, a star's path is far less complicated than, say, an asteroid's orbit in the solar system.
In any case, the astronomers undoubtedly estimated their uncertainty in the measurement, but as is often the case, the error bars don't make it in the press release.
Correction (Score:2)
Sirius is the brightest star with an apparent magnitude of -1.46. Antares is about the 15th brightest star with an apparent magnitude of 0.96.
Re:The orbit explained (Score:1)
With reguard to the paper you linked to. First off, it was a letter to the editor, which while not quite the same thing as a letter to the editor of say Discover, is a little bit differnet than a typical paper (In my experience). They typically reperesent an opposing or unrepresented view point. That said, the writer certainly has an interesting and legitimate point of veiw (ie the subjective choice of the researchers concerned with proving their points might create a pattern more agreeable with their arguments). I would argue that their conclusion, the period for mass extinctions is every 2.8 million years as opposed to ~28 million, is likewise flawed. They don't do a lot of justification for what they consider the threshold where a die off become a mass extinction. But the various researchers involved aren't looking for just any mass extinction, they're looking for a specific kind. One that kills nearly everything, everywhere caused by an extraterrestrial object. So while the periodic extinctions they find, may well have a greater significance, or stand out more than those chosen by proponants of the "galactic carousel" or Nemesis, but they really don't address the point of those proponants. Essentially they say, this period for our much larger set of mass extinctions is more statistically convincing, than this subset, which may not have a causal relation. When they do look at the impact crater data, they find that those who came before Muller, Alvarezet al introduced, unwittingly, a significant bias into the data. The writer interestingly implies in their conclusion that this introduction of human bias into the data has totally corrupted it and made it of nominal value. And like all letters to the editor, it's really just an excuse to bust out the asbestos skivvies and shout, "Flame On!"
The individual who wrote the paper doesn't acctually test any of the models. He just tests the data, determines that it has been tainted to some degree, accidently, then takes his ball and goes home. Ok. But in the end that says very little about the merits of Nemesis, or one of its competitors "the galactic carousel" (our solar system moving in basically a sinusoidal manner through the galactic plane). Again, that's probably why its in the letters section. It's an interesting addition, but really says very little about these models, and more than anything admonishes people to remember where the data they're relying on came from. As long as I'm wandering, I'd just like to say, science journal flames are the best. It also goes to show that what journals print is at least in part determined by who the paper is sent to and if they agree with you. Fermi's paper to Nature on the nature of neutrino's gets regected because everyone knows neutrinos aren't real, they're a bookkeeping method. And I'm pretty sure Ponds and Fleishman(sp?) fired off at least one paper on cold fusion which got accepted. How you get a PhD in Chemistry without knowing about convection will forever escape me. Science journals are like every other human endevour, prone to human error. So while a paper submitted to a peer reviewed journal might garner more of my respect than say a newspaper article, on its face it garners no more than another paper. After all, have not both been peer reviewed? A short anecdote about data. One lab I did way back, hit exactly the predicted value, but the catch was it was +/- 50% of that value. Oops. I took the point of view that we coincidently hit the "book" value, but would could say little if anything due to the unreliability of the data. Turns out the TA's disagreed, while you might not want to build a bridge relying on such data, you can speak about probable trends. Its just one of those things that sticks with you.
As far as divine retribution goes, that was my lame play off Nemesis the Greek Goddess of just retribution. I'm not going to comment on the state of the art in 1 million AD, and I probably couldn't accurately predict 10 years ahead. But that said, it's not going to be one comet from the Oort cloud on an earth crossing trajectory. It will be many many heading towards the sun. Who knows, maybe thousands. This would certainly complicate matters a little. But still, I get your point :).
But if Nemesis does exist, I'll certainly offer it a toast, after all without it, we'd still be rodents foraging for seeds in the brush. Then there is the whole thing about being able to appreciate the vulnerability of yourself, your tribe, whatever with respect to the void, forces of chaos etc, predict the probable form of armeggedon, and quite another to be able to circle Judgement day on your calander.
Steal this book.... (Score:1)
I certainly considering odd that a faint star should happen to be about a light year from our sun at the same time a hypothesized faint star is expected to be about a light year from our sun. But that's me. I can see how these nearly identical predictions could seem unrelated to some people. Just an observation now. But I didn't suggest that the people who found it thought that it might be, or even considered it could be Nemesis. In fact, considering that's not what it's named, I'm willing to bet they didn't. I did however highlight the similarity of this star to the aforementioned Nemesis, and provide what I thought were some interesting links about that star.
The obvious question is, given some true statements about a star, why would it be unreasonable to assume that there are true statements about that same star which are not initially given and cannot be derived?
Return of the Death Star (Score:4)
What NASA says about Nemesis. [nasa.gov]
An excellent overview from IndiaWorld. [indiaworld.co.in]
Why Nemesis isn't a wacked out theory, and might even be expected. [aplg.com]
A fairly detailed account at space.com [space.com]
We can see our clock ticking. Divine retribution seems to be a million years away But the animal smaller than dogs can take solace, as IIRC this might be Nemesis' last fly by, so they will inherit the earth for an indeterminate period of time.
The orbit explained (Score:2)
According to the links, the star is in an highly excentric elliptical orbit. A pretty good image can also be seen on the space.com link you give. This means, the orbit should be similar to long-period comets. Some graphs showing the orbit of the Hale-Bopp comet can be seen here [nasa.gov].
There are also some scientist who think the claimed 30 million year periodicity is not real, but a result of impact crater data rounded to nearest round millions of years. You can get the artcile by entering the number 9701104 in the field here [lanl.gov]. The paper has been published in an international refereed astronomical journal, Astronomy and Astrophysics [springer.de]
My personal opinion is that Nemesis is propably not lurking out there, but I think it would be worthwhile to check it.
Divine retribution seems to be a million years away
I think that in one million year, out tech can stop the comets that this star might drop from the Oort cloud. Even with present tech, we get a good early warning. A 'killer comet' would probably be detected at least half a year before the possible impact. I'd be much more worried about the Near-Earth Asteroids - they may remain undetected until a few weeks before D-day.
Re:get ready to watch it... (Score:1)
Accuracy? (Score:3)
How do they organize this work? (Score:2)