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  #1151  
Old 06-01-2018, 05:31 AM
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Default Re: Drive by science

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Originally Posted by Kyuss Apollo View Post
dinos
It was at that point Timothy realized the dinosaur had a huge blind spot underneath its neck, right in front of its massive legs.
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  #1152  
Old 06-01-2018, 08:40 PM
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Default Re: Drive by science

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Basically the latest tests have shown thrust in the same direction even when they flipped the drive around, leading to the belief measurements of thrust are related to the orientation to the earths magnetic field and aren't being produced by the drive at all. I should ad that the rig they did this in was pretty complex, not only did it have gimbals to move the drive while under vacuum, they then physically flipped the drive on the platform and did all the tests again.
Good to hear. I've suspected this for a while. You can generate (neglgible) thrust in orbit just by carrying along a magnet, after all. Though I'm uncertain what the mechanism is here, since their testbed is not moving relative to earth's magnetic field.
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  #1153  
Old 06-02-2018, 12:15 AM
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Default Re: Drive by science

From what I understand the measured thrust was so small that they think even with shielding that it's being induced in the systems wiring and equipment by the magnetic field.
Which also doesn't look good for the drive even if it works, that it produces so little thrust that induced currents in shielded equipment could still produce enough noise to eliminate any measured thrust.
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  #1154  
Old 06-08-2018, 04:47 AM
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Default Re: Drive by science

Finally, scientists have found intriguing organic molecules on Mars | Ars Technica
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  #1155  
Old 06-20-2018, 04:31 PM
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Default Re: Drive by science

TIL that there is a star that is older than the universe: the Methuselah star.

It's 14.46 billion years old and the universe is a mere 13.799 billion years old.

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  #1156  
Old 07-05-2018, 01:07 PM
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Default Re: Drive by science

Something Massive Smashed Into Uranus | Physics-Astronomy

:sniggle: title is not entirely correct. It's just that some simulations have shown that a body 1 - 3 Earths in mass could account for Uranus's unusual rotational axis and other characteristics.
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  #1157  
Old 07-18-2018, 10:26 AM
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Saturday Morning Breakfast Cereal - Twins
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  #1158  
Old 07-19-2018, 01:40 AM
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Default Re: Drive by science

For a woman that's true.
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  #1159  
Old 07-19-2018, 01:00 PM
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Default Re: Drive by science

Quote:
Originally Posted by JoeP View Post
TIL that there is a star that is older than the universe: the Methuselah star.

It's 14.46 billion years old and the universe is a mere 13.799 billion years old.

This a really good lesson in why we should only ever quote our measurements with error bars!
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  #1160  
Old 07-23-2018, 10:30 AM
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  #1161  
Old 07-25-2018, 10:49 AM
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Default Re: Drive by science

Some great nerdity about adaptive optics in astronomy.

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  #1162  
Old 08-18-2018, 03:51 AM
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Default Re: Drive by science

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  #1163  
Old 08-25-2018, 04:18 PM
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Default Re: Drive by science

I'm not sure if this is all consistent, let alone good science, but it's definitely drive-by.

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  #1164  
Old 08-26-2018, 04:45 AM
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Default Re: Drive by science

600,000,000: End of C3 photosynthesis: One of the three types of photosynthesis will no longer be possible. 99% of all species will die.



I understand their reasoning, but that's ... highly conjectural. [Also, there are more than three types of photosynthesis. Currently-extant plants use three types of photosynthesis, but plants are by no means the only photosynthetic organisms.]


But let's break that down a bit. Here's a very abbreviated synopsis of photosynthesis in plants.

The great majority of plants alive today use C3 photosynthesis. As I'm sure everyone knows, in photosynthesis, plants use solar energy to do 2 things. First, captured solar energy is used to split water molecules into hydrogen and oxygen. The oxygen is a waste product and is expelled; the hydrogen will ultimately be used in carbon fixation. The second thing plants [indirectly] use captured solar energy to do is make adenosine triphosphate (ATP), which is used to transfer captured solar energy within cells.

Then, using the ATP as an energy source, the plant combines the hydrogen with CO2 to produce organic molecules such as glucose. This is carbon fixation -- conversion of inorganic carbon dioxide to organic molecules such as glucose.


Now then, in C3 plants, the primary enzyme that allows carbon fixation is ribulose-1,5-bisphosphate carboxylase/oxygenase, commonly abbreviated as RuBisCO. RuBisCO-assisted carbon fixation works most efficiently at temperatures of around 25 degrees C. As temperatures rise above that, the reaction becomes less efficient (because RuBisCO can't bind to CO2 as effectively), and the enzyme will begin to catalyze what is essentially the reverse reaction. That is, instead of catalyzing the building of organic molecules from hydrogen and CO2, the enzyme begins catalyzing the reverse; breakdown of organic molecules into their inorganic components -- this is photorespiration.

At temperatures above about 35 degrees C, photosynthesis becomes so inefficient in C3 plants that they may lose more glucose to photorespiration than they can produce. This is especially true if it's both hot and arid, since a C3 plant needs a lot of water in order to maintain photosynthesis at high temperatures.


Some plants, known as C4 plants have a slightly different carbon fixation process, and can continue to photosynthesize at temperatures where photosynthesis in C3 plants shuts down. C4 plants still need a good deal of water to do this, but these plants -- including many grasses (including sugar cane and maize) -- do well in hotter environments, so long as they have sufficient water.

A few plants use Crassulacean Acid Metabolism photosynthesis; these CAM plants are mostly adapted for hot, arid conditions. Like C4 plants, they can maintain photosynthesis at higher temperatures than can C3 plants, but they're much better at conserving water than are C4 plants. (CAM plants include Cacti and many succulents.)

So why do the vast majority of plants still use C3 photosynthesis then? Well, so long as the temperature doesn't get too high, C3 photosynthesis is much more efficient than is C4 or CAM photosynthesis.



So, why will C3 photosynthesis supposedly be impossible in 600 million years or so? Well, as the Sun "burns" through its hydrogen reserves, the helium "ash" accumulates in its core. This causes the pressure, and therefore the temperature to slowly rise. Accordingly, the Sun is sloooooowly getting brighter over time.

This, by the way, has essentially nothing to do with climate change here on Earth. Though the Sun is getting hotter over time, we're talking on timescales measured in tens of millions of years. The heating of the Earth is far to rapid and far too drastic to have anything to do with the increasing luminosity of the Sun.


Anyway, it's estimated than in 600 million years or so, the Earth will simply be too warm for C3 photosynthesis. But 600 million years is a loooong time, even on an evolutionary timescale. After all, 600 million years ago, the very first multicellular organisms were evolving -- think of how much evolutionary change has occurred since then.

As such, I wouldn't be surprised if more efficient forms of photosynthesis evolved within that timescale. Even if that doesn't happen, what I would expect to happen is that C4 and CAM plants will gradually replace C3 plants as the dominant plants on Earth.


Of course, a point will eventually be reached where even C4 and CAM photosynthesis can't occur. At that point, assuming no new form of photosynthesis has evolved, then pretty-much everything on Earth other than bacteria and archaea will be thoroughly screwed.
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  #1165  
Old 08-26-2018, 05:21 AM
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I read some of your foolish scree, then just skimmed the rest.
 
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Default Re: Drive by science

It's interesting, some are cool and some seem like filler. Like "Men extinct?" is kinda a non event. "Scientists say that the Y chromosome won't be extinct" Um, ok, what else probably won't happen?

One that stood out to me was "13,000 earths axial tilt reverses" as this isn't a one time event nor will the axis right itself and then flip over or anything. The axis will remain mostly the same, with some variations in exact angle. What does happen is that the point of solstice and equinox changes along the orbital path in a 25,000 or so year cycle. So eventually the earth will be ever so slightly closer to the sun when summer happens in the northern hemisphere (the earths orbit being almost circular, virtually every drawing of the earths orbit greatly exaggerates the elipticalness.) Putting cycles like this on the map seems strange since they should have also included that at 26,000 years the solstices will have returned to around their current versions.
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  #1166  
Old 08-31-2018, 08:07 AM
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Default Re: Drive by science

What particle are you?
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  #1167  
Old 08-31-2018, 08:23 AM
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Default Re: Drive by science

Needs Moron option.
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  #1168  
Old 08-31-2018, 08:49 AM
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Default Re: Drive by science

So, apparently I'm an atom or whatever. "Too complicated for particle physics." Yup, that's me.
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Old 08-31-2018, 09:08 PM
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Default Re: Drive by science

A neuroscientist explains how Trump and his media allies stir up paranoid delusions in vulnerable people

Never heard of one of the sources before so checked up on PsyPost.
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  #1170  
Old 09-03-2018, 09:04 PM
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adblocker-blocker. Fuck raw story.
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Old 09-05-2018, 10:44 PM
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NoScript blocks the adblocker-blocker. I guess it's an adblocker-blocker-blocker.
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