Interview with Jane Rigby about scheduling James Webb's workload
“Give me a telescope, and I can come up with something good to do with it,” says Jane Rigby, an astrophysicist at NASA’s Goddard Space Flight Center who serves as the agency’s operations project scientist for the $10-billion James Webb Space Telescope, the largest and most powerful off-world observatory yet built by humankind.
Later in the interview she delves into the need for thrust for the JWTS, which I knew was a thing, but hearing the in-depth answer is absolutely fascinating
Photons striking Webb’s sunshield apply torque. Now, we could orient the sunshield to cancel out the torques—but we want to point the telescope at targets, not get the sunshield perfectly balanced by sunlight. So the photons hit the sunshield, they apply torque, and Webb’s reaction wheels spin up to counteract this effect and keep the telescope pointed. But the reaction wheels can only spin so fast. They occasionally have to dump their angular momentum. In low-Earth orbit, Hubble just couples the reaction wheels to the Earth’s magnetic field to slow them down. That doesn’t work out in deep space, so instead Webb fires thrusters to push against the spin of the reaction wheels. We do these momentum dumps periodically, each time using little propellant. But, as you mentioned, at this stage we have enough propellant to get into the 2040s, so Webb’s longevity is more likely to be limited by how long components last…. Honestly, though, it feels weird to be plotting the nursing-home days of this telescope when it’s still a newborn just opening its eyes!
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New dementia prevention method may be behavioral, not prescribed
The influential Lancet Commission began leading the modifiable-risk-factor movement in 2017. A panel of doctors, epidemiologists and public health experts reviewed and analyzed hundreds of high-quality studies to identify nine risk factors accounting for much of the world’s dementia: high blood pressure, lower education levels, impaired hearing, smoking, obesity, depression, physical inactivity, diabetes and low levels of social contact.
In 2020, the commission added three: excessive alcohol consumption, traumatic brain injuries and air pollution. The commission calculated that 40% of dementia cases worldwide could theoretically be prevented or delayed if those factors were eliminated.
Regarding the 'alcohol consumption' bit, my cursory research suggest this is "excessive alcohol consumption" such that it causes brain damage. As we can see by those who partake in a Mediterranean diet with its red wine, overall they seem to fair well in this arena.
The article also mentions that vision loss might be added in the future. Sensory loss makes sense, your brain has less inputs to keep it active.
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Astronomy Is About to Get Way More Exciting Because of the James Webb Telescope
For astronomers, being here on the cusp of a bold new understanding of things is like trying to fall asleep the night before Christmas. (They’re certainly less stressed out than they were on the actual night before Christmas, in 2021, in the hours before Webb launched to space on December 25.)
Next week’s lineup includes an assortment of subjects that are meant to demonstrate Webb’s range as an all-purpose space telescope that can show us the universe in infrared, a wavelength invisible to our eyes.
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Dolphins respond to unique whistles akin to names, here's how they choose their name
Unlike most animals, dolphins cannot use voices as their identifying feature because it becomes distorted at different depths. They instead invent a melody – a pattern of sound frequencies held for specific lengths of time – that they use to identify themselves for the rest of their lives. Bottlenose dolphins (Tursiops truncatus) can even imitate the whistles of their friends, calling out their names if they are lost. Additional information, such as reproductive status, can be conveyed by changing the volume of different parts of the whistle, not unlike how people emphasize certain words to add nuance.
By eavesdropping on six dolphin populations in the Mediterranean Sea, researchers at the University of Sassari in Italy revealed that differences in signature whistles were mostly determined by their habitat and population size, according to a study published in May in Scientific Reports. Sound travels differently in distinct environments, so dolphins create signature whistles that best suit their surroundings, according to the study authors.
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Objective Reality May Not Exist, Scientists Say
This reminded me of a post I saw on TikTok which brought up that if our shadow is 2d representation of our 3d selves, then what if our daily existence going through time (4d) is a shadow of a 5d... thing? I could see this being broadened to be "objective reality."
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There are more galaxies than even Carl Sagan imagined - Big Think
But when it comes to the number of galaxies that are actually out there, we’ve learned a number of important facts that have led us to revise that number upwards, and not just by a little bit. Our most detailed observations of the distant Universe, from the Hubble eXtreme Deep Field, gave us an estimate of 170 billion galaxies. A theoretical calculation from a few years ago — the first to account for galaxies too small, faint, and distant to be seen — put the estimate far higher: at 2 trillion. But even that estimate is too low. There ought to be at least 6 trillion, and perhaps more like 20 trillion, galaxies, if we’re ever able to count them all.
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This blows my mind. In some ways it reminds me about the Mythbusters episode about the plane on a treadmill.
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Monarch butterfly numbers in Mexico rise by 35%
Monarch butterflies hold a special place in my heart. And it has honestly helped me today to hear this news.
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The secret world beneath our feet is mind-blowing – and the key to our planet’s future
[Auto Generated Summary]:
Bacteria, fungi, plants and soil animals, working unconsciously together, build an immeasurably intricate, endlessly ramifying architecture that, like Dust in a Philip Pullman novel, organises itself spontaneously into coherent worlds. "The idea is to let the plants put back at least as much carbon and minerals as we take out."Tolly tells me that "The green manure ties up nutrients, fixes nitrogen, adds carbon and enhances the diversity of the soil. The more plant species you sow, the more bacteria and fungi you encourage. Every plant has its own associations. Roots are the glue that holds and builds the soil biology."The other crucial innovation is to scatter over the green manure an average of one millimetre a year of chipped and composted wood, produced from his own trees or delivered by a local tree surgeon. As Tolly explains: "It isn't fertiliser; it's an inoculant that stimulates microbes. The carbon in the wood encourages the bacteria and fungi that bring the soil back to life." Tolly believes he's adding enough carbon to help the microbes build the soil, but not so much that they lock up nitrogen, which is what happens if you give them more than they need. If we can discover how to mediate and enhance the relationship between crop plants and bacteria and fungi in a wide range of soils and climates, it should be possible to raise yields while reducing inputs.
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"We have figured this out, yes," said Dimitri. "With lasers. It was very illuminating experiment."
"Was that a pun?"
"It was!"
"Good one!"
We both laughed. Stratt glared at us.
I am reading Hail Mary by Andy Weir finally and this little interchange made me laugh out loud. Honest nerd humor as they geeked out in a part of the story.
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James Webb telescope reaches its final destination, 1 million miles away
What an amazing achievement. I cannot wait to see what it starts to see and what we start to learn from it.
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Antivaxxers Want You To Believe Vaccines Don't Work Against the Delta Variant. They're Wrong.
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Biden proposes $250 billion investment in research
As excited as Biden's infrastructure bill is, I find this even more exciting.
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Is the surface of the sun solid
/u/Solestian asked:
This might seem like a stupid question, perhaps it is. But, let's say that hypothetically, we create a suit that allows us to 'stand' on the sun. Would you even be able to? Would it seem like a solid surface? Would it be more like quicksand, drowning you? Would you pass through the sun, until you are at the center? Is there a point where you would encounter something hard that you as a person would consider ground, whatever material it may be?
/u/VeryLittle gave this excellent answer:
Before anyone goes mocking this question, it's actually very clever. Let me explain.
The sun is fluid, all the way through, even if that fluid is very different than any you might be used to on earth. It's a plasma, meaning that the electrons are separated from the nuclei (though the level of ionization varies with temperature and depth). This traps light, specifically photons, which bounce back and forth between charged particles.
The deeper you go, the denser this plasma gets, as it gets compressed by all the weight on top of it. The outer most layers of the sun that you see, 'the photosphere', is just the part where this plasma has such a low density that photons can escape from it. But it's actually a layer about 300 km thick, because the average distance a photon can travel here before bumping into a charged particle is a few 100 km. This means they escape, shining off into the solar system. This does a good job of giving the sun an apparent 'surface,' but it is by no means solid, and the sun extends well above the photosphere.
So if you were invincible, impervious to the incredible heat of the sun, what would happen if you tried to stand here? Well, you'd fall like a rock. The density of plasma in the photosphere is far less than the density of earth's atmosphere- you'd fall as if there's almost no drag. It would be like freefall- very, very hot freefall.
So would you ever stop falling? Yes! Why? Bouyancy, from your relative density. Denser things sink, like rocks in water, but less dense things float, like helium balloons in air. And remember, the sun gets denser as you go down. The core is a hundred times denser than you, so if I tried to put you there, you'd float up. Wherever you start, you'd eventually stop when you reach the part of the sun that is just as dense as you, about 1 g/cm3. Coincidentally, that's halfway down through the sun.
Needless to say, I don't know how you're planning to get yourself out of this mess, but I hope you brought some spare oxygen tanks.
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This is the fastest random-number generator ever built
Using a laser and the random fluctuations in light to generate random numbers is a fascinating and brilliant idea.
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Without spoiling anything, we just watched the latest episode of Shameless and I have to tell you all: Mythbusters busted the myth that the ending moment works that way.
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Thread about a moon rock in the Whitehouse
At least, that's where it starts, and it goes on to reveal the geological mysteries of the moon and how much there is still left for us to learn in the universe. Sometimes it can feel like we know everything there is to know and that there are no mysteries remaining, and that simply is not true. This thread highlights a number of them about the moon, our moon.
Our moon is large compared to our planet, and we have no idea how it formed. There are theories but we have no idea if they are right. Fascinating stuff.
Definitely read the full thread.
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