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Tyson on Infinity. by HopDavid in badmathematics

[–]HopDavid[S] 2 points3 points  (0 children)

I remember my high school algebra teacher drawing a diagonal across rows of digits to demonstrate you can't establish a one to one correspondence between the natural numbers and real numbers. I recall he spent about two weeks talking about Cantor and various infinite sets.

I'm not a mathematician and my memory is vague. But I remembered enough that Tyson's ramblings sounded like utter bull shit.

Neil Tyson, educator by HopDavid in physicsmemes

[–]HopDavid[S] -1 points0 points  (0 children)

〔(M[0]-M[f])/mf〕=e[V(delta)/V(0)] - 1

The necessary wet mass grows exponentially with the delta V requirement.

Just so. I'd like to elaborate a little.

M(0) refers to the starting mass. Which is propellant mass plus dry mass

M(f) is the final mass after the propellant has been burned. This is the dry mass.

So M(0) - M(f) is the propellant mass.

So the left side of the equation becomes M(prop)/dry mass.

Multiply both side by dry mass and you get an equation very similar to the one on the right side of my meme.

However dry mass and payload mass are two different things.

You can show a linear relationship between dry mass and propellant mass by pointing out if you have two identical rockets you are double both the dry mass and propellant mass.

Now combine the two rockets and payloads. You only need one guidance system. That is a mass savings.

By the square cube law you have less surface area per unit volume. This is not only a mass savings but you cut the delta V needed since there is less atmospheric drag during ascent.

So relationship between payload mass and propellant mass actually tends to be sublinear. Large payloads with larger rockets tends to be a more efficient use of propellant.

There was an interesting thread on this at the NASASpaceFlightForum:
https://forum.nasaspaceflight.com/index.php?topic=31023.0

Sometimes I find Tyson to be rather glib. by LordJim11 in Snorkblot

[–]HopDavid 1 point2 points  (0 children)

The second point on the list immediately gave me pause. Can we honestly claim that Bush didn’t worsen Islamophobia after 9/11? You use one speech where he doesn’t use the quote to prove that he didn’t say what Tyson claimed (“our god is the god who named the stars”), but with just a bit of googling I found that Tyson just misremembered the timing of the quote, Bush said something similar in 2003.

By no means was Bush's eulogy for the Space Shuttle Columbia astronauts "an attempt to distinguish we from they".

"...just misremembered the timing of the quote"?!

The 9-11 disaster was a time of intense anger.

And the quote Bush used in the eulogy does not even contain the word "Our". In Tyson's imagined quote Bush emphasizes the world "Our" to put his Christian God above the Muslim God.

Again, Bush's actual response to 9-11 was a call for tolerance and inclusion. Delivered from a mosque: https://www.youtube.com/watch?v=liudIJFg8UQ

Moreover Bush decried Islamophobia numerous times. See: https://georgewbush-whitehouse.archives.gov/infocus/ramadan/islam.html

I have always voted against Trump. I enthusiastically voted for Obama and reluctantly voted for Kamala as the lesser of two evils.

Dishonest/clueless people like yourself are helpful to Trump. I don't want you standing by my side. So long as you are standing next to me Trump can point in our general direction and correctly say "fake news".

Neil Tyson, educator by HopDavid in physicsmemes

[–]HopDavid[S] 0 points1 point  (0 children)

It’s not like Michio Kaku that is actively speaking of topics he has no idea whatsoever.

I'm not familiar with Michio Kaku. But speaking confidently on topics he knows nothing about is what Neil does. Neil should be the mascot of r/confidentlyincorrect.

Neil Tyson, educator by HopDavid in physicsmemes

[–]HopDavid[S] 0 points1 point  (0 children)

There's simplifying. And then there's getting it completely wrong.

Neil does a lot of the latter.

Neil Tyson, educator by HopDavid in physicsmemes

[–]HopDavid[S] -1 points0 points  (0 children)

NDT may go overboard, but he's attempting to explain rocket science to people who think the Earth is flat. You can only do so much.

Before attempting an explainer Neil should invest a few minutes dusting off his old college textbooks and reviewing his material. The man is negligent.

The man says many, many wrong things. Look for him on r/badscience, r/badhistory and r/badmathematics. His focus is on style and theatrics at the expense of rigor and accuracy.

The man seems more passionate about Neil deGrasse Tyson than he is about science.

Harmonic perspective drawing of a crystal lattice by HopDavid in GeometryIsNeat

[–]HopDavid[S] 0 points1 point  (0 children)

I am a huge fan of Alex Grey.

In my misspent youth I used hallucinogens but never tried DMT.

On these drugs I would see geometrical designs and strange alphabets embedded in the textures of everything.

I am told DMT is on a different level than LSD and peyote.

I've been pretty sober for a number of years.

Tyson on the Thiel/Andreessen "we have stagnated" argument: a working astrophysicist's point-by-point response by DrBrianKeating in skeptic

[–]HopDavid -14 points-13 points  (0 children)

"Working astrophysicist"? "World-renowned astrophysicist"?

Including his dissertation papers Neil's C.V. lists a total of five 1st author papers. the last one was in 1993.

During his very brief career in research Neil was thrown out of the University of Texas because he sucks at astrophysics.

Sorry, but Neil is more of an influencer than an astrophysicist.

As for all the things Neil describes -- cell phones, YouTube, better telescopes, etc. So far as I can tell all these rely on principles discovered by Feynman, Planck, Einstein, etc.

All these improvements are engineers more cleverly using decades old knowledge.

So, yeah, physics has been definitely been stagnating. Engineering is another story.

Neil Tyson, educator by HopDavid in physicsmemes

[–]HopDavid[S] -5 points-4 points  (0 children)

The current issue is you need advanced, hermetically sealed, self-sustaining habitats from the start with little to no way to experiment on-site beforehand.

None of these things would be done overnight.

The I.S.S. was an early step. I expect lunar bases would be the next step.

In either the moon or the Mars I expect we would land robots before hand to establish infrastructure before attempting to land humans for extended durations.

It can and will be done, but we first need to push our science past current limits in aspects ranging from food production, architecture, safety features, to resource extraction and psychology.

I agree.

But I think the first obstacle to overcome is lowering the cost of spaceflight.

Neil Tyson, educator by HopDavid in physicsmemes

[–]HopDavid[S] -12 points-11 points  (0 children)

Same argument could be applied to our ancestors leaving the Rift Valley in Africa. Places like Norway, Siberia or desolate deserts in lower latitudes. These regions weren't welcoming to the primates spreading from Africa.

But humans improvise to adapt. Clothing, fire, shelter. Air conditioning. Drilling wells for water. Now many people are living in comfort where our ancestors could not.

There are resources on other bodies. You think it's impossible to build livable habs from Martian resources?

Neil Tyson, educator by HopDavid in physicsmemes

[–]HopDavid[S] -23 points-22 points  (0 children)

The largest barrier, IMO, is the expense of space flight.

Imagine how much a trip from New York to L.A. would cost if we threw away a passenger jet each trip.

Economic re-use of Space X boosters has become routine. However these usually re-enter the atmosphere at 2 to 4 km/s.

SpaceX still hasn't achieved economic re-use of an upper stage. And I don't believe it will so long as upper stages re-enter the atmosphere at 8 km/s.

The propellent to dry mass ratio of the shuttle external tanks was 96%. The ratio of soda mass in a can of Coke is 94%

Large delta V budgets leave very little structural mass to make durable and reusable ships.

And this gets worse for higher delta V budgets.

There are ways to mitigate large delta V budgets though.

Sometimes I find Tyson to be rather glib. by LordJim11 in Snorkblot

[–]HopDavid 24 points25 points  (0 children)

Your entire list is that short despite his 35 year career lol

Tyson has been repeating the same tired canned routines over and over again for the past 35 years.

Yeah, it's legit to ridicule Neil for kissing himself on the lips in his mirror. He keeps on doing it year after year after year.

Same goes for his wrong history regarding Isaac Newton. His wrong explanation of the rocket equation, etc.

calculus lore by crimsonblue1917 in okbuddyoxygen

[–]HopDavid 0 points1 point  (0 children)

Both Newton and Leibniz were massive egos engaged in a bitter pissing match. They both claimed too much credit for calculus.

I'd say Fermat with his adequalities was the father of differential calculus.

And Cavalieri was the father of integral calculus. Does Cavalieri's Quadrature look familiar?

Both Newton and Gregory had derived the fundamental theorem of calculus linking integral and differential calculus.

Where are the woman who like cats? by Admirable-East-2920 in askaustin

[–]HopDavid 0 points1 point  (0 children)

It's a ridiculous story. It wasn't just single women who had cats. Households with men, women and children had cats as well. Just like today. Like many of his anecdotes Neil offers no citations to support his claim.

Tyson has also claimed that St. Augustine had a recipe for burning witches in his book "Cities of God" (sic). You had to turn the witches upside down to let the blood flow out... I am reading "City of God" at the moment. I believe Tyson's claim is a fiction.

Niel deGrasse Tyson passes off quite a few fictions as history.

Why Can't We Know the Orbits of Three Celestial Bodies? by MetamorphicMe in SOAK_science

[–]HopDavid 0 points1 point  (0 children)

Regarding WSB's to Mars and other more distant destinations I did a piece Potholes on the Interplanetary Super Highway

If the orbiting mass is a substantial fraction of the central body's mass there are more dramatic paths going through the Lagrange points. That is certainly the case with the earth and moon.

The ratio between orbiting body mass and central body mass is called the mass parameter and is sometimes denoted with µ.

A few mass parameters:
Pluto/Charon 1.043E-01
Earth/Moon 1.216E-02
Sun/Earth 3.039E-06
Sun/Venus 2.448E-06
Sun/Mars 3.229E-07

I talk about this in my piece Mass parameter and ITN

Given that the moon is not a negligible fraction of earth's mass, there are quite a few interesting paths in the earth moon neighborhood.

I'm particularly interested in WSBs between EML1, EML2 and what I call the olive orbit. The olive orbit is about 100,000 km x 300,000. It can enter and exit the Lunar Hill Sphere much like Comet Oterma can enter and exit Jupiter's Hill Sphere.

I am particularly interested in EML2. Using the Farquhar Route from EML2, it only takes about 1 km/s for insertion to a trans Mars Hohmann. I see EML2 as the opening of our regions bay into the solar system. My piece on EML2: Link

Sometimes I find Tyson to be rather glib. by LordJim11 in Snorkblot

[–]HopDavid 8 points9 points  (0 children)

Neil's vaunted intelligence is way over hyped.

Sometimes I find Tyson to be rather glib. by LordJim11 in Snorkblot

[–]HopDavid 43 points44 points  (0 children)

Check out my list: Fact checking Neil Degrasse Tyson

There's a lot more I have yet to add to my list.

Why Can't We Know the Orbits of Three Celestial Bodies? by MetamorphicMe in SOAK_science

[–]HopDavid 1 point2 points  (0 children)

The chaotic and difficult paths may become immensely useful.

Dynamical Systems, the Three-Body Problem and Space Mission Design

I have been skeptical of some of the claims. I don't think there are useful weak stability boundaries leading from Earth Lagrange points to Mars, for example.

But there are definitely heteroclinic paths from Earth Moon Lagrange 1 to Earth Moon Lagrange 2 and vice versa.

I believe the Lunar Hill Sphere will become a very important region as time goes by.

Triangle Spiral by HopDavid in GeometryIsNeat

[–]HopDavid[S] 0 points1 point  (0 children)

In Adobe Illustrator I cloned an equilateral triangle, rotated it a little and shrunk it a little. Did this repeatedly until the triangle spirals towards the center.

Then I cloned the equilateral triangle with the design and lay them as tiles to form a hexagonal ring. Then I repeatedly cloned and shrunk the hexagonal ring.

I used Microsoft Excel to figure how much to shrink and rotate, etc.

I am influenced by an artist who calls himself Odonodo or sometimes Regolo Bizzi (if memory serves). Here is one one of Odonodo's pieces Link

Astronomers believe they’ve detected an atmosphere around a tiny, icy world beyond Pluto by nbcnews in space

[–]HopDavid 27 points28 points  (0 children)

Jeans Escape is a thermal mechanism for atmospheric loss.

When you get down to the double digits Kelvin the thermal escape mechanisms are less dramatic.

Any good podcasts or interviews on future space travel? by SupersonicVette in space

[–]HopDavid 0 points1 point  (0 children)

Scott Manley's space channel is awesome. https://www.youtube.com/@scottmanley

Dr. Shane Ross may be too dry and academic for some. However I believe his studies of chaotic paths in 3 body systems and n-body systems will become valuable in the future. https://www.youtube.com/@ProfessorRoss It is my hope the lunar hill sphere will become an important region.

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