Max Fagin ๐๐ด๐โ๐
@MaxFagin
Followers
11,770
Following
462
Media
1,397
Statuses
6,894
Aerospace engineer, pilot & astronomer. Space systems/resources @BlueOrigin @OrbitalReef . Opinions my own, but call me out if I'm an asshole about them. He/him.
Seattle, WA
Joined October 2009
Don't wanna be here?
Send us removal request.
Explore trending content on Musk Viewer
YOKO BIRTHDAY PARTY
• 294980 Tweets
#TheTraineeSeriesEP8
• 246416 Tweets
Alain Delon
• 232040 Tweets
Chelsea
• 220109 Tweets
ANILPIN BLOSSOM AROMATIC
• 148736 Tweets
#เธเธฃเธเธตเธงเธฑเธEP11
• 146854 Tweets
#เธเธดเนเธเธ เธฑเธเธเธดเนEP3
• 123903 Tweets
PPOP POWER WITH SB19
• 90816 Tweets
ISANG MILYONG KALAKAL
• 79912 Tweets
ASESINADO
• 78685 Tweets
ใฉในใใใใ
• 68017 Tweets
ใชใผในใใฃใณ
• 47802 Tweets
Mocejรณn
• 42554 Tweets
Manchester City
• 38102 Tweets
Man City
• 34712 Tweets
ๆบๆฐ็ฉ่ช
• 33269 Tweets
Palace
• 31283 Tweets
Sterling
• 30020 Tweets
CRAZY COMPACT PHOTO
• 22825 Tweets
Brentford
• 20565 Tweets
Emery
• 19465 Tweets
ใใคใใใฃใใ
• 18758 Tweets
#ใญใณ่ใใณ
• 16258 Tweets
D-9 TO CHANYEOL SOLO
• 15359 Tweets
ๆธกๆตทๅ
็
• 15241 Tweets
ๅคฉๅๅ
็
• 14626 Tweets
#้ใ็ฉใใๅญค็ฌใชๆญปใ
• 13603 Tweets
OUR SEA
• 12333 Tweets
ใขใฉใณใปใใญใณ
• 11430 Tweets
Lookman
• 10357 Tweets
Pinned Tweet
@ysamjo
I don't take comfort in *knowing* the future will be better.
I do take comfort in a robust data-informed extrapolation that we have made the world better by most available metrics, and are highly probable to continue doing so.
1
3
18
Hi. Actual astronomer here. Three things:
1) Saturn isn't in Capricorn now or on April 29, it's in Sagittarius.
2) The last time Saturn was station retrograde in Capricorn was 1992 (not 1666)
3) Astrology doesn't work. Stop trying to pollute this horrible tragedy with nonsense.
582
17K
77K
November is here, and that means a massive shift is coming. And by "massive" I am of course referring to the redefinition of the kilogram unit of mass that the world has been building up to for more than 100 years. Let me explain:
872
26K
52K
I encountered a delightful little astrodynamics proof last week when an astronaut casually stated it as a fact, and when I looked skeptical, he just smiled and said, "Check it yourself."
Here's the statement:
"It takes 2 hours to orbit at the surface of any object made of rock"
110
2K
15K
20/ The BIMP is expected to recommend this new definition be adopted this month, ending a journey begun more than a century ago. The SI unit system will finally be a truly universal system, free of any human artifacts. And that to me is a profoundly beautiful thing.
107
788
8K
5/ Every unit you've ever used is "officially" derived from these 7 units. A gallon? Officially 0.003785 m^3. One atmosphere of pressure? Officially 101325(kg/(m*s^2) of pressure. 100 Watts? Officially 100 kg*m^2/s^3. 12Volts? Officially a 12 kg*m^2/(s^3*A). Image:
@usnistgov
50
2K
8K
How it started How it's going
(2012) (2020)
74
400
8K
@JI_RS_
@AdrienneACox
For a baby born in space, astrologers would create their predictions the same way they do for babies born on Earth: They would make shit up.
18
120
5K
8/ Finally, in the 1960s, technology advanced enough to redefine the second not from an artifact (like the Earth) but from a fundamental property of the universe. Today the second is defined as the time it takes an electron in a cesium-133 atom to oscillate 9,192,631,770 times.
39
653
5K
@sjanderson144
Hi. Actual astronomer here. Three things:
1) Saturn isn't in Capricorn now or on April 29, it's in Sagittarius.
2) The last time Saturn was station retrograde in Capricorn was 1992 (not 1666)
3) Astrology doesn't work. Stop trying to pollute this horrible tragedy with nonsense.
36
208
5K
Dear astronomers at star parties: Do *NOT* insult the quality of another astronomer's equipment. Ever. The night sky is for everyone. I don't care if someone sets up next to you with a literal cardboard tube on a stick. You say "Welcome to the star party!"
88
337
4K
19/ By measuring the attractive force between two charged plates, and following an incredibly intricate process to calibrate out the effects of the Earth's gravity, the kilogram can now be defined in terms of nothing more than the physical constants of our universe.
43
714
4K
4/ At the base of this tower are the SI base units. Just 7 SI base units define every other unit in existence. They are:
Kilogram, kg (mass)
Meter, m (distance)
Second, s (time)
Kelvin, K (temp)
Ampere, A (electric current)
Candela, cd (luminous intensity)
Mole, mol (quantity)
34
603
4K
1/ I've had an unhealthy fascination with metrology (the study of measurement) ever since my 2nd year as a physics major when I took a class devoted to duplicating historic physics experiments, so please indulge me for going into heavy detail (get it?) about the kilogram.
42
301
4K
Oops. I accidentally reffered to the Bureau International des Poids et Mesures as "BIMP" when the correct abreviation is "BIPM". I also mistook the decade when the speed of light definition of the meter was adopted. It was the 1980s, not the 1960s.
168
166
3K
14/ For 129 years, the kilogram has been defined as just the mass of a physical artifact stored in a vault in France (called the International Prototype Kilogram, the IPK).
Image credit: "The State of the Unit"
38
595
3K
16/ And this is frustrating since, over the last 100 years, there is evidence that the IPK has actually lost some of its material (even though, paradoxically, the IPK is the one object in the entire universe that *cannot* loose mass.
37
361
3K
18/ Until now that is. Finally, this month, after decades of work and multiple false starts, metrologists are ready to redefine the kilogram by a complex but incredibly precise experimental setup.
3
369
3K
2/ So what actually *defines* a unit of measurement? If you're American, you probably know a mile is 5280 feet and a foot is 12 inches and an inch is 2.54 centimeters etc. But where does this chain of definitions end? Is it turtles all the way down?
25
208
2K
11/ The meter finally left artifact based definitions behind in the 1960's when timing equipment was precise enough that the meter could be defined as the distance light travels in a vacuum in 1/299,792,458 of a second.
21
262
2K
9/ And since we have good reason to believe that electrons are constant properties of our universe, this definition is good everywhere and for all eternity. (And for a memory trick, since it make a year equal to ten million pi seconds long, +/-0.5%.)
15
196
2K
To put that another way: The radius and mass of an object *don't independently matter* for its low orbit period; it's only the density that matters. And if you plug in the density of a typical rock (~2700 kg/m3), you get almost exactly 2 hours!
9
63
3K
7/ For example, in the 1940s, 1 second was defined as 1/86400 the time it takes the Earth to rotate once. In the 1950s, the second was redefined as 1/31556925.9747 the time it takes the Earth to orbit the sun.
14
267
2K
12/ And since we have good reason to believe the speed of light is a constant property of our universe, this definition of the meter is good everywhere and for all eternity. (Another memory trick, you can just remember the speed of light is 300 million m/s. That's good to 0.1%)
23
179
2K
3/ It's actually not! For all units (even the imperial units used in America) the answers all end with the Systรจme International (SI) unit definitions established and maintained for over 100 years by the Bureau International des Poids et Mesures (BIMP) in France.
18
203
2K
6/ There's no standard foot or pound sitting in a vault in Washington DC. All units are officially defined (what we call 'traceable') through SI base units. But how are these 7 SI base units defined *themselves*? Well historically, they were defined by reference to an artifact.
5
200
2K
13/ All the other base units in the SI system have long since been redefined in terms of physical properties of our universe that are constant and unchanging. All that is, except the kilogram. Ah, the kilogram! The kilogram has stubbornly eluded redefinition.
6
217
2K
17/ (So yes, if some careless technician accidentally chipped some metal off the IPK, then the weight we ascribe to atoms would go up. The IPK *always* weighs 1 kg by definition).
10
181
2K
As soon as I finished this check, I remembered ~2 hrs from a paper somewhere. I found it later: The distribution of asteroid rotation speeds vs size from 10.1093/mnras/stab412.
Notice the cutoff? Above a certain size, there are no asteroids that spin faster than once every 2 hrs
7
47
2K
Turns out, if you take the relation between a sphere's density, mass and volume and use it to expand the equation for the period of a low circular orbit to be in terms of R (instead of the more familiar equation expressed in terms of both R and M) then all of the R terms cancel!
20
45
2K
Addendum: Nothing special about rock either, we can generalize this statement to orbits around objects made of other stuff:
Metal (~7000 kg/m3): 1.2 hrs
Gas giants (~1400 kg/m3): 2.8 hrs
Ice/water (~1000 kg/m3): 3.3 hrs
29
35
2K
My first thought was that it couldn't be right since Low Earth Orbit period isn't 2 hours; it's 1.5. But of course,๐isn't a rock; ๐has an iron core that bumps our density up to ~twice that of rock, (and actually makes Earth the densest planet in the solar system)
5
37
2K
15/ Unlike time and distance, mass is more difficult to measure precisely, so attempts to create a universal definition of the kilogram have failed to match the precision of simply taking the IPK out of the vault and weighing it every so often.
13
195
2K
10/ The meter had a similarly long and remarkable journey. Defined first as 1/10,000,000 of the distance from the equator to the north pole, then as the distance between two marks on a platinum-iridium bar in France,.
9
167
2K
Is that a coincidence? Nope! Same physics. Most asteroids are mostly rock, and once they get big enough to be held together by their own gravity, if they *were* spinning faster than once every 2 hours, then parts of them would (by definition) be in orbit.
3
22
2K
Material would get thrown off their equator until the asteroid shrank/spun down to the 2 hrs period limit. I remember seeing this figure in grad school, but I hadn't connected it to the general conclusion that "all rocky objects have low orbit periods of ~2 hours". Very cool!
2
25
2K
@Rob_Milly
@xtaldave
Only if you assume the Earth's orbit hasn't changed since the time of the ancient Babylonians. But it has. Quite a lot. The Babylonians can be forgiven for not compensating for that. Modern astrologers have no excuse.
12
59
2K
My second thought was that ~2 hrs did seem like a surprisingly good approximation for the low orbit periods of the rocky objects I could call to mind.
๐: 1.5 hrs
๐: 2.0 hrs
๐ด: 1.8 hrs
3 different sized ~rocky objects, each ~2 hr low orbit periods.
So what's going on here?
5
18
2K
@DefinitionsC
@AcademicAstro
I don't know dude. I already got two degrees in the subject (BA in astrophysics, MS minor in astrodynamics). Looking into it more just seems excessive.
28
51
1K
Astronaut application: Submitted.
๐จโ๐๐๐ฐ
38
20
875
@AcademicAstro
Just because something is *deep* doesn't mean its *accurate*. Ancient natural philosophers wrote in great depth on the structure of matter, but anyone today who thinks everything is made of mixtures of fire, water, earth, and air is still wrong.
7
32
796
While I was at SpaceX, 3 colleagues left for Blue Origin.
While I've been at Blue Origin, 2 colleagues have left for SpaceX.
And the mood at each going away party was: "You're awesome and we will miss you. Congrats on the exciting new job!"
Space twitter: Take note. Be decent.
21
50
811
"Can you prove it doesn't work?" isn't a proper scientific question. Science isn't about proof (and you can't prove a negative anyway).
The correct scientific question is "Can you provide evidence that it does work?". And on the subject of astrology, the answer appears to be no.
@MaxFagin
Curious, can you prove astrology does not work? Honest question.
Thanks in advance. ๐
10
0
2
20
99
764
First pass at the entry profile for Starship along with the timing of major events from the video. We can see the effects of the flaps being used to mitigate deceleration and heating. A textbook lifting entry!
12
109
787
@KimILSungVEVO
Evil plots like this are why we need a definition of the kilogram based on unchangeable physical constants. Only then will the world be safe.
33
43
647
@MtStHelensWA
@MegavoltService
Feud update: St. Helens has decapitated Rainier and is now wearing its severed head as a trophy.
10
44
636
@WadeCaves
I'm aware. But there are only two possible reasons astrologers wouldn't have needed to update their coordinate system in the last 2000 years:
1) Astrology works all the time, perfectly, for everyone.
2) Astrology doesn't work.
10
9
539
@damianaswan
That was the standard when the IPK was built in the 1890s! The IPK was made to have a mass equal to 1000 ml of water of a known composition at a known temperature and pressure. Water being too difficult to work with was one of the incentives to make the IPK in the first place.
8
22
534
I spent four years of school building rocket payloads to study the aurora. The first thing I ever machined myself to fly into space went to space to study the aurora.
But despite all that, I had never actually *seen* the aurora.
Until tonight. ๐ญ
7
17
440
@newspace_Cho
Isn't it just? This might be my new favorite "fun fact" about orbits to share with students (which is good, since my previous "fun fact" was very fun, but required using the phrase "orthonormal basis" ๐ฅด)
2
0
418
Literally 36 hours ago I was presenting a requirements document to a room full of engineers for an mockup EVA suit, trying to explain why we needed the requirement "suit shall accommodate anthropometrics from 5th percentile female to 95th percentile male". This is why.
Let's talk about spacesuits, specifically Extravehicular Mobility Units, and being a
#ladyastronaut
.
The EMUs on the ISS were designed more than 40 years ago, with a 15-year shelf life.
11 of the original 18 are still in use.
Only 4 are on the ISS.
Those are the only EMUs.
92
2K
4K
4
98
394
Hi. I'm the "NASA astro physicist" who did that. Three things:
1) "Astrophysicist" is one word.
2) I'm not an astrophysicist (not all astronomers are astrophysicists)
3) Your annoyance is of no relevance as to whether or not astrology works.
4) Astrology still doesn't work.
11
42
387
@MaryRobinette
You're absolutely right. I should have said, "the problem was *acknowledged by NASA management* as far back at 2007." Indeed, it was noticed long before that, but no one listened.
3
9
371
@isaac32767
You're right, I should have said US Customary, not Imperial Units. Thanks for the correction!
4
23
346
Did you know that you can just order road signs? And did you know that you can customize them to say anything?
4
19
360
@grajillas
@damianaswan
Oh yeah, Definitely. The density of water changes a lot depending on temperature and how hard your tap water is, but for classroom purposes, a liter of water should be 1000 +/- 50g, especially if you use lab grade beakers to pipet exactly 1000 ml.
5
12
330
@mattmcirvin
You're right! I forgot about the spectral definition and jumped right to the speed of light definition. Thanks for the catch!
5
22
316
Students and professionals studying astrodynamics: Anyone want a free copy of an equation sheet? I started it in grad school, and it's *far* from all-encompassing, but way easier to haul around than a textbook. Happy calculating! ๐ซ๐๐ Download link:
15
68
328
@jaybeebrtweets
Good question! Now that the definition is truly unchanging, the IPK will be free to drift slowly away from exactly 1kg. The material loss rate is very slow though. Only ~0.00000001 kg per CENTURY. So for all practical purposes, the IPK will still be 1 kg.
7
35
300
NEW
#SPACEELEVATOR
IN FICTION ALERT!!! This time it's from
#TheWanderingEarth
. Let's see how it stacks up against some of the other fictional portrayals of Space Elevators.
5
15
313
I've watched hundreds of satellite transits through my telescope, so my first thought when I saw this great eclipse video was "Oh, that's a satellite!"
But alas, the angle that
@smartereveryday
and
@redshirtjeff
were both able to capture it means it is *not* a satellite...๐งต
4
7
313
This is a horrible take. Scientists are allowed to have a life outside of our scientific work. And if we choose to spend some of that life talking about our scientific work with people who find it interesting (and who might otherwise not hear about it) then so much the better.
7
31
294
This honestly is the one thing that makes me furiously unwilling to let astrology go as a harmless past time: The pretense that horrible tragedies were portended *after the fact*. It implies that IF astrology worked (and it doesn't), astrologers are still bad at their job.
@sjanderson144
Damn shame you couldn't have used this information BEFOREHAND to help prevent it. Oh, but I see that everything you've posted is bullshit and have made up sciencey sounding stuff to seem legit to fit what happened after the fact. Thanks
@MaxFagin
for schooling this guy.
6
3
122
13
42
289
At a family wedding this weekend.
Questions from my 40-70 year old relatives:
So how's work?
Is work good?
What are you working on?
Questions from my 8-13 year old relatives:
How do you think Hogwarts funds itself?
Do you think Athena is gay?
What's a space elevator?
8
18
260
Astrophysics: The study of a universe that contains:
~3x more dark energy than matter
~5x more dark matter than baryonic matter
~6x more men than women studying "Why?"
...But where textbooks will only list the first two as "Big Problems"
We can do better. We must do better.
that feeling when youโre sitting in a talk on dark energy and thereโs 24 men in the audience and...4 women
20
9
225
6
46
254
Yes dammit. When an orbital mechanics equation plausibly contains the terms "dV/dr", "V_h*S" and "ฮฒ_max", I *am* going to spend 15 minutes on the extra algebra required to make those terms appear next to each other. There's a principle at stake here.
8
59
244
Delivering a talk to high school students about astrodynamics, and challenged myself to come up with a slide that explained what orbital elements were without using:
1) Equations
2) The phrase "orthonormal basis set" ๐คช
11
24
240
If you stuck your hand out of
#Tiangong1
right now (currently at 160km and 7.8km/sec) the wind would exert about as much pressure on your hand as the weight of this 5cm square of tissue paper. But the aerodynamic heating would be painful. Like grabbing a 100W incandescent bulb.
7
73
229
@TheSpaceGal
That actually surprises me. Not the popularity of astrology (that irritates me, but it doesn't surprise me) but rather that you *aren't* completely inundated with this stuff. You either have great twitter filters, or astrologer just know not to tangle with you!
7
3
223
Pilot after landing: "Thank you for flying with us. The safest part of your journey is over; now you have to get in a car. Good luck."
Clearly, I'm not the only one who is frustrated by having to give the "yes, air travel is still much safer than any other mode of travel" talk.
7
24
221
@VulcanCentaur
Twitter: Why are you reporting this tweet?
Me: It contains graphic or disturbing content.
1
1
213
After 2 weeks of printing, I will now set out to assemble this amazing 1:100 scale model of the ISS. And just for fun, I'm not going to follow the directions, I'm going to try to replicate the historical assembly sequence. This will take time, but hopefully <15 years. Let's go!
8
19
217
The Mars 2020 rover landing sites are now being voted on at
#Mars2020LSW
. Here is my exclusive peak behind how the site selection process works.
1
55
202
I found the aviation equivalent of "Speak friend and enter"
4
12
204
Yes!!! I love updating this slide, and I love it when I don't have to add another โ. Welcome to Mars
#Zhurong
, and congratulations to the entire
#Tianwen1
team!
3
62
194
I really hate our gleeful embrace of this fictional narrative that the world is getting worse. It isn't! By almost any metric, this is the best time in history to be alive, and tomorrow will continue to be better.
Source:
20
44
193
@East_From_Eden
You know, I'll bet that champagne cork that went flying off still somehow landed in a soccer net.
1
3
193
Dear smartwatch astronomy app developer: I'm flattered, but your app is of little use to me, as I am not a god who resides in heaven and looks *inward* on the celestial sphere.
In the future, please render your sky maps correctly.
Sincerely,
Not A God, Just An Astronomer
8
23
180
@CarolynPure
@sjanderson144
@AnneOrtelee
The cool thing about astronomy is that (unlike astrology) you can check that the things I am saying are correct for yourself. Nullius in Verba. Just wake up at 5AM tomorrow and look to the southeast.
6
7
164
I previously expressed a hope that this pandemic would mean the end of two bad ideas:
1) Opposition to vaccines
2) Polynomial curve fitting of exponential trends
I'd be happy if astrology joined that list.
Pluto canโt catch a break. โThe report laid the blame on Pluto. Apparently, the small but powerful planet โdeals with huge financial matters, masses of people โ and viruses.โโ
11
12
54
6
21
165
@MaryRobinette
One bit of good news, this problem was noticed as far back as 2007, and new standards were written to accommodate better anthropometrics in future suits. It's just that (as you said) the ISS uses a 40-year-old design.
From NASA's Integration Design Handbook SP-2010-3407
1
15
161
If you (like me) were disappointed that you didn't get your letter from Hogwarts when you were 11, just remember that there is a Hogwarts class that you can take in real life: Astronomy.
iโm pretty positive that one of the reasons iโm an astronomer is because itโs the only Hogwarts class I can actually take in real life.
50
96
3K
1
20
165
Everyone, please meet Beetlejuice the ๐ฆ. I adopted this cuddly ball of feathers 4 months ago, and he's one of the best decisions I've ever made! I promise not to turn this account into a pet photos account, but please indulge me this thread, because I ๐him so very very much.
5
7
158
Why is
#TheExpanse
season 4 so wonderful? Because we get not 1 but *2* examples of entry vehicles employing drag augmented supersonic retropropulsion via peripherally oriented jets (my thesis subject)! Look at those plumes!๐๐โ๏ธ
(oh also great characters, setting, writing etc.)
6
39
154
I am a trained astronomer right up until someone asks me what their star sign is... Then I become a trained asshole.
6
11
145
Carried my telescope to the beach to catch something I've always wanted to watch up close: The full moon rising over the ocean.
#supermoon
6
18
145
When
#SLS
lifts off tomorow, remember: It's not over until splashdown. Celebrate every milestone and risk retired, but this is the most complex first flight of a vehicle since the space shuttle. And it is going to last *weeks*.
Launch is the inauguration, not the culmination!
2
24
150
Envelope expanded. Well done to the
#Starship
team!
If the ship's FTS did fire just a few seconds before MECO (still unclear?) then it's probable there will still be visible re-entry streaks over New Guinea around 14:10 UTC (11:10PM Local). Be on the look for a light show!
3
4
145
@elonmusk
@mcjamez
@_jameshatfield_
@danielcincu
@Alex_Parker
To clarify Elon's tweet: The ISS does have a few dim external lights, but they are *not* what you see from the ground. When we see the ISS with the naked eye, it is almost entirely due to it being a large object that reflects a lot of sunlight.
3
2
141
No please random twitter person. Do continue to lecture me about the very thing I spent 4 years of my undergrad/post-bacc building detectors to study. I'm sure I didn't learn any thing about Dark Energy that you can't teach me in 280 characters.
15
7
140
1) But my favorite portrayal of space elevators in fiction is
@ErikWernquist
short film "Wanderers". Accurate climber speed and accurate tether cross-section, and accurate portrayal of where the first space elevator is likely going to be built: On Mars.
7
6
139
I am where I am in my career today because of hard work, support from friends and family, and luck. But today, I ran into a former SpaceX colleague who reminded me of a factor I often forget: I am where I am today because I did theater in school to fulfill a sports credit.๐งต
8
20
139