@DrPhiltill's Threads
Lunar landing ejecta of large craft can even destroy spacecraft that are ORBITING the Moon, like @LRO_NASA, unless you can time the Collision Avoidance (COLAs) correctly. We put this into NASA's guidelines for Moon landings. See page 15: nasa.gov/directorates/h…
2/ This is why we need international agreements ASAP where we agree to hold each other harmless for some degree of ejecta spray that we put onto each other's lunar hardware. We need to agree to design all our hardware to handle it, and that it's our own fault if we don't.
3/ Because it is simply impossible to do major lunar activity without putting spray all over the Moon onto each other's hardware. This is because the Moon is unlike Earth: NO ATMOSPHERE to stop the super high velocity dust that comes from a rocket engine during landing.
Niiiice! I think we need some more #FootballSpaceAnalogies
If the football were made of neutron star material, it would weigh 423 trillion kg (923 trillion lbs) and the final score would be zero zero. #FootballSpaceAnalogies
If the Mercedes-Benz Stadium is used as heavy lift rocket launch pad, the FieldTurf will be heated to 2/3 the temperature of the sun (4000 K), which will melt it resulting in delay of game. #FootballSpaceAnalogies
We're back at the cancer center due to some complications (getting better, though!) and the onco nurse Jennifer was asking why it is so hard to land a rover on Pluto. I was explaining about the need to carry lots of fuel to slow down to go into orbit & how expensive that is.../1 
2/ She says, "I wonder if you could send a rocket that would land on a planet, do its own maintenenace, fuel up, and hop to the next planet. Is that possible?" Wow!
We told her that's EXACTLY what we've been working toward with the recent "steam powered asteroid hoppers"...
We told her that's EXACTLY what we've been working toward with the recent "steam powered asteroid hoppers"...
3/ So we showed her the recent headlines about the steam-powered asteroid hoppers that re-fuel themselves and keep exploring. She said "WOW, I GUESS GOING TO SPACE CAMP PAID OFF!" 😄😄😄
Yes, she went to @SpaceCampUSA. It's super cool our oncology nurse is a Space Camp graduate.
Yes, she went to @SpaceCampUSA. It's super cool our oncology nurse is a Space Camp graduate.
Wow, so much science will come from this flyby. At a glance, it looks like each major piece is made of multiple smaller ones (the lumps with lines between), the craters could be sinkholes between the lumps, idk. This could be crucial to explain planet formation. @NewHorizons2015
2/ I mean, I don't know what the mission team is discussing about it, but it REALLY looks like this could lead to a detailed model of that vital, but mysterious stage of planet formation when meteoroid-sizes cluster and merge to form bodies large enough for gravity to take over.
3/ And if it does, then that is cause for celebration, because that is EXACTLY what the mission promised to give us. It went to look at a pristine object that has not been banged up by collisions in the inner solar system, to try to see an early stage of planet formation.
I love this for reasons that may be non-obvious: the connection between the Moon Earth's biological environment. Please let me explain. (1) The red color on the Moon is the result of light refracting through Earth's "tertiary atmosphere", which we have BECAUSE OF LIFE... 1/n
2/n ...and BECAUSE OF THE MOON. When the Moon formed (we believe by a giant impact), it blew off Earth's primary atmosphere, which was probably a lot denser like that of Venus. A secondary atmosphere then seeped from the Earth, and then life came along and transformed it...
3/n This "tertiary atmosphere" is the one we know today, with lots of oxygen and nitrogen. Now the red color is mostly from the way nitrogen scatters out the blue sunlight leaving red to shine on the Moon in an eclipse, but if you looked at the Moon with a spectrometer...
🙉 It took me far too long to realize why this cup filled to the rim & overflowed. I took it empty from the cabinet & pushed the middle button so it "should" have filled only half. Smh & lol. But there's cool physics here. (Btw, we use refillable k-cups for the environment.) /1
2/ See the interesting pattern in the coffee dust that leaked through the filter? This reminds me of asteroid impacts on the Moon because there are (what look like) primary and secondary impacts in this pattern.
3/ On the Moon, and asteroid hits at high velocity and blows out ejecta, which then strike the Moon at much lower velocities. Those are the secondary impacts. This drip pattern looks like a central impact site surrounded by places where the splashes went out and hit secondarily.
I'm choosing to annoy my fellow science nerds with this statement: I like the term "Dark side of the Moon." It was always "dark" in the sense that we lacked knowledge of it, not that it lacked sunlight. We allll know this & don't need to be nerd-splained, right? 😝 Also... /1
2/ ...the dark side of the Moon stopped being dark in 1959 when the Soviets flew Luna 3 around it and sent home some pictures. So the Moon used to have a dark side, but it doesn't any more. Right? 👊😅 But to be more accurate...
3/...really, we have barely explored either side at all. There's so much we don't know, even from the side where most of the missions landed. So shouldn't we say the Moon has twoooo dark sides: the Slightly Darker Dark Side, and the Slightly More Illuminated Dark Side?
Fun conversation at dinner tonight, since my oldest daughter Jess participated in pebble accretion research in the lab of @joshuacolwell and @astroaddie at @UCF two years ago. Josh, Addie and Julie Brisset are doing reduced gravity experiments to understand planet formation.../1
2/ The earliest part of planet-formation is well-understood, because molecules fuse to form dust (like snowflakes growing in a cloud), then the dust particles easily stick to each other by cohesion. But after they grow to the size of pebbles they will bounce instead of stick...
3/ This is the "bouncing barrier" of the planet formation process. So Josh, Addie, Julie, and others in their team have been devising experiments to study how gravel-sized particles can form ever-larger clumps until they are large enough for gravity to take over...
Liftoff of a steam-powered, water-mining, interplanetary spacecraft, a new way to explore asteroids and moons that never runs out of rocket fuel during extended missions. This was a super cool project. Thanks @NASA, @kriszacny, and the super engineers at @Honeybee_Ltd.
2/ This spacecraft prototype twisted a coring tube down into the simulated Ceres regolith, heated it to extract water from the hydrated minerals, then heated the water to steam to lift off. This demonstrated how it continuously refills its propellant tanks and hops around Ceres.
3/ At the 6 second point in the video you can see one of the gray coring tubes (with the spiral flutes) before liftoff. This is what twists down into the soil to extract water for rocket fuel. The mission can study the water for science, and it can carry other payloads, too.
I only wish the OST didn't have the clause allowing any nation to get out of it with only a 1-year notice. One year isn't enough time for other nations to react, to prepare space missions that could prevent a nation-going-rogue from making a land-grab on the Moon. Therefore... /1
2/...in view of the weakness of the OST, the best course is for all the nations of Earth to work together to quickly establish permanent presence and vigorous activity on the Moon, to proactively prevent any nations from going rogue and making land-grabs.
3/ This might seem like an abstract concern, but won't be for long. The expanding access to space and the revolutionary advancement of robotics ensures this will be a concrete reality in just a few years. There is no time to lose. We need vigorous investment in space, now.
Starting 10am New York time Saturday, @CosmoQuestX will stream 40 hours of SCIENCE to raise funds for science. It will be packed with guests (me in hour 13 😄), giveaways, great science, and ways to help.
Tune in: Twitch.tv/CosmoQuestX.
Learn more: Hangoutathon.org
Tune in: Twitch.tv/CosmoQuestX.
Learn more: Hangoutathon.org
ALL the science starts at 10am eastern US time (3 pm London) tomorrow (Saturday), but here's the description of my piece in hour 13. Please tune in as we discuss these space rocks and how they can change our world.
New plan. I will be live on the hangout-a-thon at 1am Eastern US time. Please join us!
You can see the reflective thermal control material blowing off the descent stage at ignition. In one lunar ascent, the camera with the astronauts looking down saw a large sheet of it tumbling across the Moon for kilometers. With no air, there was nothing to stop it.
2/ If you freeze th video at the right moment, you'll see red, green, & blue pieces flying away in perfectly alignment. Really they're the same piece. The camera used a color wheel to get red, green, & blue images sequentially. It made each piece look different colors as it flew.
3/ The sequential red, green, & blue frames were merged into a single, full color video after the signal came down to Houston. Objects that weren't moving looked full color. Objects that moved fast had the red, green, and blue images of it spread out across the screen.
Just published this paper: a method to grade the fidelity of simulated asteroid materials. sciencedirect.com/science/articl…
We use "fake asteroids" for many reasons, including to do tests on spacecraft. But many engineers have mis-used the simulants, resulting in false test results... /1
We use "fake asteroids" for many reasons, including to do tests on spacecraft. But many engineers have mis-used the simulants, resulting in false test results... /1
2/ This can result in $100M's of loss and waste if a spacecraft fails to work during a mission. The test says it will work, but if the test is based on a simulated asteroid material that has the wrong properties then the test is just fooling everyone. So we need to prevent this.
Weird thought for the day: in a sense, we are all "inside" the sun. What Voyager 2 just did: it went outside the sun. I say this because, unlike a planet, the sun does not have any material surface other than the surface Voyager 2 just crossed.../1
2/ When you look see pictures of the sun, what looks like its surface is really an optical effect, not really a material surface. It is called the photosphere...
3/ It is where the plasma has gotten just a little less dense -- just a little. Below the photosphere, photons are absorbed and re-emitted by the molecules but the molecules usually collide before re-emitting the photons, so it changes the photons' directions: it scatters them.
I still wonder how falling ejecta could completely bury the boulders without also burying the grooves. So where are the boulders??? In any case, @CLASS_UCF co-sponsored Ramsey's lecture on this theory, viewable here: connect.arc.nasa.gov/p806n591s4h/?l…
2/ Another problem: the grooves are filled with conical craters. If these are supposedly where the boulders bounced, then they should be be in order earlier-to-later as you move away from Stickney Crater. However, you can see overlapping craters where they are in the wrong order.
3/ The alternative theory is that the grooves are the result of tidal stretching of Phobos, where regolith is collapsing into the structural cracks of the body. This allows that the collapse craters form in random order along the faults. It better fits the visual data.
Yes, for sure! When I ran a lab at NASA, I had to do calculations on liquid nitrogen & compressed gases so in case the bottles busted they wouldn't displace too much air from the room and suffocate everyone. It's a real risk. Keep car windows open & all spaces well-ventilated.
NASA is SUPER safe. Once it took us several months to get approval to use a single bottle of helium, same as used in flower shops for balloons. Even if the whole bottle dumped at once, the room's oxygen would drop from 20% only to 19.5%, so it was safe. But we had to PROVE it.
The worst example of TOO MUCH safety was when they told the PhD scientists we couldn't boil water in the chemistry lab, because OSHA defines hot water as a hazardous substance, and we didn't have the necessary paperwork approved to work with that particular substance 👿...
We arrived for rhe second chemo treatment today. We brought dry ice this time to help reduce the risk of permanent nerve damage in her hands and feet. Last time we used regular water ice on her hands & feet but it was awkward.../1
2/ My sister died of colon cancer 4 years ago. She had been in chemo for 10 years & had really bad "chemo hands & feet" (as she called it): almost total loss of sensation from the nerve damage. She would walk out of her shoes and not even realize it. But there's now good news...
3/ Medical studies have proven that putting ice on your hands and feet while that one drug is administered produces a statistically significant reduction of nerve damage. The medical staff here recognizes it and lets us know when it is time to apply the ice. But it is weird...
The main news today is our family's journey with cancer. My wife's chemotherapy chose today while I was at a conference to make her hair fall out. Gigi knew this day was coming but still she cried for a long time when it began 😞 Her hair dresser Nelson was a hero... /1
2/ He said Gigi is the 12th woman in chemo that he has cut. He didn't just shave her head. First he cut it to shoulder length so she could get a photo. The he cut it to chin length for another photo. Then he gave her bangs. Then finally he turned the chair so she couldn't watch.
3/ Gigi had 2 friends there telling how beautiful she is after her head was shaved, before he turned the chair for her to see. This may sound like a small thing, but it meant the world to her. Thankful for awesome friends on this journey. Here's Gigi (center) with her new wig❤
Today it begins. Gigi and I are at the cancer center for her 1st chemotherapy treatment. It will take 8 hours, but the entire process takes 10 or 11 hours with lab work and consultations. Two days ago she had surgery to put a port under her skin for the frequent needles. /1
2/ Yesterday met with a surgeon about the multiple required surgeries. It is happening so quickly, it hasn't felt real. Gigi says the same.
But now it is real. She just finished lab work and we walked to the chemo center. Gigi was taken to the room. They'll call me, shortly.
But now it is real. She just finished lab work and we walked to the chemo center. Gigi was taken to the room. They'll call me, shortly.
3/ But Gigi is VERY encouraged. Running that marathon was vital. I dont think I mentioned it before, but Gigi got FIRST PLACE for her age group! She was worried she couldn't even finish. Her only goal was to finish, but she got first place. 🙏 (I need an emoji smiling with tears)
1/n Sad news to explain why I missed the New Worlds conference this weekend: my wife was diagnosed with breast cancer. We spent the week planning her chemo and surgeries. Her prognosis is good, but we were devastated because now she can't run a marathon she trained for all year.
2/n She was supposed to run the Space Coast marathon in 2 weeks. Last year she collapsed at 20 miles. This year her times are good enough to qualify for the Boston. But 2 weeks out the doctors say she must start chemo immediately. No Space Coast Marathon 😞 But we made a plan...
3/n I told her we should find a marathon THIS weekend, anywhere in the country, and we will go there so she can run it. She isn't quite ready. She ran 20 miles last weekend and needed more time to recover. But this is her last chance for an entire year so she is doing it!
In one of those Twitter coincidences, these appeared adjacent on my screen. I just wrote a paper on the "Economic and Social Justice Needs to Broaden Ownership of In-Space Industry." This is a previously unexplored topic that will have great consequence within a few decades.
2/ The study of economic growth deals with issues that become less relevant once we have largely autonomous industry off-planet. Growth needn't be governed by supply, demand, labor, land, finance, or social rules. Growth can be purely metabolic (matter & energy) and VERY fast.
3/ This potential for rapid scale-up is the reason why robotic space industry, when it has adequate machine intelligence, will bring an economic revolution. It won't merely be a way for enterprising people to do some business. It will deeply change the structure of civilization.
There are 150 to 450 planets in our solar system. The desire to keep the number small is a cultural bias from the prescientific days when planets were viewed as gods reigning in their orbits, ruling our lives through the horoscope. The essence of that meme still survives... /1
2/ The names of the days of the week are from the names of the 7 ancient planets (which included the Sun and Moon as planets)
Saturn(n)-day
Sun-day
Moon-day
(The rest in Spanish)
Miercolos = Mercury
Martes = Mars
Jueves = Jove or Jupiter
Viernes = Venus
Similar in Anglo-Saxon
Saturn(n)-day
Sun-day
Moon-day
(The rest in Spanish)
Miercolos = Mercury
Martes = Mars
Jueves = Jove or Jupiter
Viernes = Venus
Similar in Anglo-Saxon
3/ The days of the week were named as part of a horoscope system so people could always know which planet was ruling at any given moment. It was a deep desire to find order and meaning in life, looking to the seemingly powerful lights in the sky for that.
To be clear: our new paper shows that asteroids were reclassified as non-planets not on the basis of orbit-sharing, but their geophysical properties: they are unlike planets. The argument in 2006 (that they were reclassified because of orbit sharing) is factually untrue. /1
2/ If we apply the exact same standard to Pluto that we applied to asteroids, then it is most definitely a planet. This is what the published scientific record shows.
3/ The standard that was applied to asteroids, first in thinking they were planets, later in realizing they should not be, was completely in-line with the geophysical definition of a planet that came down to us from Galileo in the Copernican Revolution.
The air will slowly leak away to space due to Mars' low gravity, so we'll need to continually make it up by adding more. We can do that by bringing small water-rich asteroids to burn up in Mars' atmosphere. Moving them is slow, but easily fast enough to maintain Mars.
2/ You could also simply bring icy asteroids into Mars, not just to maintain the atmosphere, but to make its atmosphere thick in the first place. My co-author argues that this is not ideal since it would take too long to make Mars live-able.
3/ So he argues the we should use the Martian soil to get the initial dose of oxygen, making Mars live-able very quickly. Then we could bring ice from space just to maintain the Martian atmosphere over the long term, because we only need a slow process to do that maintenance.
