TESS Discovers Its First Earth-Sized Planet (mit.edu) 82
A reader shares a report from MIT News: NASA's Transiting Exoplanet Survey Satellite, TESS, has discovered its first Earth-sized exoplanet. The planet, named HD 21749c, is the smallest world outside our solar system that TESS has identified yet. In a paper published today in the journal Astrophysical Journal Letters, an MIT-led team of astronomers reports that the new planet orbits the star HD 21749 -- a very nearby star, just 52 light years from Earth. The star also hosts a second planet -- HD 21749b -- a warm "sub-Neptune" with a longer, 36-day orbit, which the team reported previously and now details further in the current paper.
The new Earth-sized planet is likely a rocky though uninhabitable world, as it circles its star in just 7.8 days -- a relatively tight orbit that would generate surface temperatures on the planet of up to 800 degrees Fahrenheit. The discovery of this Earth-sized world is nevertheless exciting, as it demonstrates TESS' ability to pick out small planets around nearby stars. In the near future, the TESS team expects the probe should reveal even colder planets, with conditions more suitable for hosting life. Slashdot reader RockDoctor shares a link to the paper at Arxiv, adding: The 'b' object in the system (the largest perturbation on the star's light) is estimated at 2.61*Radius_earth, and 22.7*Mass_earth for a surface gravity of 3.332*littleG_Earth. If it has a "surface" in any recognizable sense rather than gradual transitions between gas mixtures, liquid mixtures, and the digested remains of any "metals" (lithium or higher, as the astronomers say).
The 'c' object is more poorly constrained. The authors give a radius (0.892*Radius_earth, derived from the depth of the eclipses), but only put an upper limit on the mass at
The TESS mission has a Science Requirement "of providing 50 transiting planets smaller than 4*Radius_earth with measured masses," and the 'b' planet fits that criterion, but the 'c' planet does not, yet, have a well-enough constrained mass. Keep on catching planets!
The new Earth-sized planet is likely a rocky though uninhabitable world, as it circles its star in just 7.8 days -- a relatively tight orbit that would generate surface temperatures on the planet of up to 800 degrees Fahrenheit. The discovery of this Earth-sized world is nevertheless exciting, as it demonstrates TESS' ability to pick out small planets around nearby stars. In the near future, the TESS team expects the probe should reveal even colder planets, with conditions more suitable for hosting life. Slashdot reader RockDoctor shares a link to the paper at Arxiv, adding: The 'b' object in the system (the largest perturbation on the star's light) is estimated at 2.61*Radius_earth, and 22.7*Mass_earth for a surface gravity of 3.332*littleG_Earth. If it has a "surface" in any recognizable sense rather than gradual transitions between gas mixtures, liquid mixtures, and the digested remains of any "metals" (lithium or higher, as the astronomers say).
The 'c' object is more poorly constrained. The authors give a radius (0.892*Radius_earth, derived from the depth of the eclipses), but only put an upper limit on the mass at
The TESS mission has a Science Requirement "of providing 50 transiting planets smaller than 4*Radius_earth with measured masses," and the 'b' planet fits that criterion, but the 'c' planet does not, yet, have a well-enough constrained mass. Keep on catching planets!
A nice step (Score:3, Interesting)
Even if this hasn't found any "good" planets yet, even just the process of ruling out systems to visit is helpful...
Going to be pretty exciting when we launch our first real interstellar probe with a possibly viable destination planet, even if any return findings would take quite a long time to happen...
Why can't Americans use standard units? (Score:2, Insightful)
Even Celsius would be better than using the awful Fahrenheit for measuring temperature.
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Speaking of morons, if you had been able to read past the first paragraph of your own reference, you would have seen this:
According to a story in Germany, Fahrenheit actually chose the lowest air temperature measured in his hometown Danzig in winter 1708/09 as 0 F, and
only later had the need to be able to make this value reproducible using brine.
The History section also has other interesting info on why the Fahrenheit scale is set up the way it is. You should read it, or maybe you should stick with more appropriate sources of information [dummies.com].
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So unless you lived in Danzig in the early 18th century, it's still not very human centric. The majority of human beings will never really experience 0 F. Sticking your hand in your freezer doesn't count as "really experiencing."
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"The majority of human beings will never really experience 0 F."
0F isn't too bad if theres no wind blowing (or the wind is behind you.)
It was a cold winter this year, One night it got down to -35F (actual temperature, not just wind chill)
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-20 C (basically 0 F) is my usual threshold hold for "does it get cold here." If it regularly gets that cold, you'll probably want to have a block heater on your car. So if people ask "what's that cord coming out from under your hood? Is it an electric car?" then you know it doesn't get cold.
I once had to repair a broken cord on my block heater when it was closing in on -50 C (actual temperature). That was a fun job.
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The majority of human beings will never really experience 0 F.
You obviously live somewhere warmer than I do. It gets at least close to 0F every winter, and often below that. And my brother lives up north, where 0F in January or February is a heatwave.
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I doubt it. But the vast majority of the world's population lives somewhere warmer than either you or I do.
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Erh... no. What Fahrenheit did was to "calibrate" (I'll use the term loosely here) his scale by the freezing point of a saturated solution of ammonium chloride with the goal to avoid negative temperatures because in his time there was no way to artificially create lower temperatures, additionally the freezing point of water as 32 degrees (why 32? Maybe he liked the number, who knows) and the body temperature of a human (at 96, of course). So a human is four times as hot as ice compared to ammonium chloride
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Re:A nice step (Score:5, Insightful)
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Do try to keep up. People are moving towards engineering designs for both spacecraft and "launching lasers" for a ~24 year mission to the Alpha Centauri system. The spacecraft are limited to being around a gram in mass, and I've seen no description (yet) of how to get the data back (I've got ideas myself). In recent history terms, we're in around the position of Goddard in the mid-20s.
The corollary of that analogy i
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Slashdot is read by a bunch of engineers who are entering their "bah humbug" phase of life. They're the ones who like to use the term "space nutter."
I'm not entirely unsympathetic. For someone who lived through the 60s and 70s, the subsequent rise of anti-intellectualism and pseudo-intellectualism must be frustrating.
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Maximum Effort (Score:1)
I hate to break this to you, but we will never visit another star system. Not even with satellites.
And you also though 640k was enough for everyone... it is not I say!
To put things in perspective, after our own sun, Proxima Centauri is the next closest star to us at about 4.3 light years distance. It would take a craft travelling at our maximum velocity over 70,000 years to get there.
I am really curious why you think basically empty space has a maximum speed.
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At least they didn't label this one as "earth like." I really hate when I read that head line to only read the article and see that it is anything but earth like.
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Just 'cause the measuring stick read 10 because you went metric, don't get all cock-y. What matters is the unit, and centimeters ain't inches.
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Metric units? How about proper writing instead of fucking retarded pseudocode like "3.332*littleG_Earth".
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Also, don't carp at me for the editor copy-and-pasting my text after Slashdot rendered it. I carefully included an ampersand-LT-semicolon and the mass limit in my script, but the editor copied the un-matched left-angle-bracket and it went wobbly for a paragraph or several (I can't really tell where in my original comment the editor intended to terminate (comment #1 on submission page [slashdot.org])
There were other bits
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You ought to know by now that anything using remotely special characters is likely to break. It's not TeX, FFS.
Is it too hard to write "roughly a dozen Earth masses" or "a third of the Moon's lactose content" or whatever?
Sorry, your attempt to convince me that you do not totally suck has failed.
Slashdot is really bad today (Score:2)
An interesting science story and it's full of Trump bullshit.
Are undetected planets "dark matter" ? (Score:3)
During my lifespan, we've discovered more and more planets at interstellar distances. They seem to be a common part of most star systems, based on direct observation of nearby stars and based on increasingly consistent models of stellar evolution. This is confirmed by just the kind of planetary survey work in the original article.
But we've also discovered increasing numbers of planets in interstellar space. Some estimates include 100,000 rogue planets in the Milky Way alone. At increasing distances, and especially at extra-galactic distances, they don't radiate enough of anything to detect directly. And the increasing numbers detected hint that many may have a non-stellar origin. If these are mare prevalent than realized, if they are collected matter in the vast spaces between galaxies, would they not fit the very definition of "dark matter" ? Matter that is indetectable by radiating energy, which they would only radiate incredibly weakly in interstellar or intergalactic space where their only energy sources to radiate are from nuclear decay, thermal collapse, and re-radiation of the background 3 degrees K cosmic hiss? If it's dense enough, it might even occlude more distant high energy radiation sources, modifying the very data from which we deduce cosmic red shift and the presence of "dark matter" ?
It's an appealing theory, and requires only a missing understanding of rogue planet formation. It doesn't require obscure and un-measurable re-interpretationsn of physics to invent exotic, non-baryonic matter.
Re:Are undetected planets "dark matter" ? (Score:5, Informative)
Unfortunately for your idea, or any idea that relies upon ordinary baryonic matter to account for the dark matter in galaxies, measurements of the abundances of light elements such as hydrogen, deuterium, helium and lithium, together with models for the nucleosynthesis of these elements in the very early stages of the universe, set limits on the amount of baryonic matter in the universe. Those limits preclude amounts of baryonic matter large enough to produce the gravitational effects which are the basis for dark matter.
Good idea, but strong evidence argues against it.
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I'll add that I was reading journal articles in the late 70s making pretty much that argument and referring to the question as having been dead since the 1960s. Planets won't make up the necessary amount of non-luminous matter to account for the motions within or between galaxies.
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It doesn't matter how many habitable planets there are, unless you have something truly exceptional to offer, you shouldn't have *any* hope of ever leaving this planet.
First off - there's currently 130 million babies born every year. 356,000 every day. It's unlikely we'll ever start launching people into orbit anywhere near that quickly, much less across interstellar distances that will require many orders of magnitude more energy. Which means the vast majority of people born on Earth will never leave.
We
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Interesting that you think that people can reproduce in artificial habitats throughout our solar system without, at some point, a large number of people, well, leaving Earth...
Won't happen in my lifetime. Probably not in your lifetime (I'm assuming you're young now). But sooner or later, it's going to hap
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Large is a relative term. 2000 people leaving Earth would be sufficient, assuming they survived and prospered. Assuming the population doubles every generation, it only takes twenty generations to reach 2 billion people. There's genetic evidence that our species was almost wiped out to the point that we went through such a genetic bottleneck once already.
Even a million people emigrating every year would still be only be 0.014% of the Earth's population.
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200 people would be sufficient, providing they could manufacture living volume (including farming volume) fast enough.
You'd need to carry a few thousand more-or-less random sperm and egg samples too. That'll take up a couple of cubic metres of well-shielded gamete-bank volume. And you'll need an incentive for the talking uteri to carry them - something like : "If you have a baby from the bank, then you'll be able to have another one of your own" would probably
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>On the other hand, the first year would probably get rid of Elon Musk, half Trump's clan, and a shit-ton of other B-Ark crew.
Unlikely. Musk maybe, though I think even he has said he might like to visit. Anyone who enjoys their creature comforts, or wishes to live a long life, is unlikely to have any interest in emigrating. Life in space is likely going to make the lives of monks look positively decadent in comparison for at least several decades, and maybe centuries. And the health effects of radiat
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Just for starters, you're going to be essentially vegan, whether you like it or not, for the foreseeable future. The 10% efficiency of conversion of sunlight into calories in the shape of beefsteak is going to make that a rare treat. Then you'll have to find someone to kill it and butcher it. Butchery is hard, dirty work.
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True, though insects may become popular fare as well, as they already are in many places - with something like a 90% efficient conversion rate of plant matter into protein, and the ability to digest cellulose-rich material that's useless to us except as compost, they offer an excellent low-impact meat source.
Rotation is an excellent solution in free space, though somewhat more problematic on a plaent's surface, where you need a support structure and constant influx of energy to dissipate friction losses. S
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Yes. Perfectly true. So, you don't do that.
At the moment, the only even slightly feasible planets for inhabitation are Earth and Mars. Combined, they expose ab
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There's plenty of oxygen on Mars to rejuvenate the atmosphere to breathable levels (assuming we're talking extreme-high-altitude evolved humans) - it's just mostly locked up in iron oxides at the moment - we'd probably need some sort of microbial terraforming to release it - I've heard estimates that it could be done in only a few centuries. One we have the technology to create them of course /wry.
>chewing up less than a million 10km across asteroids
Except, there's quite likely not anywhere near that man
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The current Mars atmosphere is largely useless for anything beyond heating (looks like 15x the partial pressure of CO2 on Earth), no argument there. But you need to consider the sheer tonnage of sand on Mars, and the fact that it's extremely oxygen rich. Mars is red because it's covered in iron oxide. Get some water into the air as well to dramatically increase heating, and you could make the planet minimally livable. The raw materials are there, what's needed is truly mind-boggling amounts of energy to
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This is a process that, if the materials were available (not accepted), would render the surface a long way from habitable. A few tens of thousands of years later, say 23456 CE, we'll see what th
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The timescale is even more debatable than the available resources. At any rate - terraforming Mars isn't a dream I think it's time to tackle any time soon. It has potential to become another oasis in the long term, but in the near term I suspect the real treasures will be elsewhere.
Fair enough, obligation can be a powerful motivator. And as someone who mostly chooses not to waste the brain-sweat despite the opportunity, I certainly can't argue with that perception. The idea of a society built by people
I give up... (Score:2)
Society's insanity has won. I read that as, "TESS Discovers Flat Earth Sized Planet"
In the meantime (Score:1)
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What I wrote was ""2.5*Mass_earth. Which then got copied from the Slashdot-rendered version, and caused the edit window to barf.
The Slashdot editor is venerable, and not in a good way. I mean, I know how to encode M{ocross} and so on for the proper typography. Which is damned-all use here.
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Fighting the damned system here. It's different on every second site.