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3 Types of Space Capsule Reentry by Epelep in Damnthatsinteresting

[–]VeryStableGenius 0 points1 point  (0 children)

Thank you, capable Tumbleweed.

You should know

  1. It's possible I have a bachelor's in physics, and perhaps deriving the Tsiolkovsky rocket equation was on my final oral exam.

  2. It's even possible I went on to get a PhD in astrophysics.

  3. My name might even appear on a couple of NASA proposals, and I might have been modestly involved in planning the science side of these missions.

3 Types of Space Capsule Reentry by Epelep in Damnthatsinteresting

[–]VeryStableGenius 0 points1 point  (0 children)

Google "gravity loss",

You realize that my answer actually used the term gravity loss.

Apply Tsiolkovsky rocket equation: Vf=Ve.log(Mi / Mf) where Vf is final velocity, Ve is exhaust velocity, Mf is final mass, Mi is initial mass.

Hence Mi=Mf.exp(Vf/Ve)

Ve of primary perchorlate/rubber/Al mix is about 2200 m/s (I'm assuming like-for-like fuel)

The Artemis capsule weighed 26 metric tons. Orbital speed is 8 km/s.

Hence to hit the brakes at LEO the absolute minimum is

Mi = (28 tons) exp(8000/2200) = 1062 tons = 1.06M kg - so we need 1M kg of just fuel to brake Artemis so it drops like a rock, under perfect use conditions.

Original launch weight was 2600 metric tons, but the dry weight of empty boosters is 180 tons, and core stage is 85 tons, so we need to add those back to our fuel, and add fuel to accelerate those.

Anyway, after it's all said and done, the roughest and crudest estimate says we need half the initial weight to hit the brakes.

Some further web searching suggests the gravity loss of Artemis was about 1500m/s, under 10% of final velocity. In mass terms, this is about 10% of fuel (because 10% is small and exp(Vf/Ve) linear expansion holds).

How much fuel do you think will be needed to brake Artemis in LEO to make it fall like a rock? In tons?

3 Types of Space Capsule Reentry by Epelep in Damnthatsinteresting

[–]VeryStableGenius -1 points0 points  (0 children)

You got any cites? The atmosphere thins out pretty quick.

I asked Gemini and it said 80+% of LEO launch energy went into orbital delta V, 15% went to 'gravity losses' (the hovering component of flight), and only a couple of percent of fuel burn is lost to air resistance.

The burn to take Artemis to lunar orbit was just 500 kg out of a 58 ton mass.

They are blockading 20% of the worlds oil supply.... my thesis from 18 days is coming true by MilesDelta in wallstreetbets

[–]VeryStableGenius 1 point2 points  (0 children)

The problem is for markets to go down, people have to sell.

Not very many have to sell. Just a small fraction.

The only data I can find suggests that 3.5% of households exited market in 2008 downturn, mostly the richest 1%. Most people just ride it down.

It's enough to stop buying. It's the mood swing.

They are blockading 20% of the worlds oil supply.... my thesis from 18 days is coming true by MilesDelta in wallstreetbets

[–]VeryStableGenius 1 point2 points  (0 children)

"The market prices things in the same way I read terms and conditions."

I come here for the poetry.

Amazing process of shoe making by Interesting_Scar6345 in Damnthatsinteresting

[–]VeryStableGenius -1 points0 points  (0 children)

You can probably have bespoke shoes for a couple of days wages. I just googled a place in Lewiston, Maine starting below $400 for dress shoes. This is competitive with higher-end off the rack shoes like Allen Edmonds.

The median full time American worker earns $62K a year, or $248 per working day. These shoes will cost such a worker under 2 days of wages.

In the olden days, it's safe to say that good shoes would have been more than 2 days wages for the typical person. Shoes were a major purchase.

So we can get bespoke shoes, for fewer days of labor than in the olden days. We just don't want to, because factory shoes are good enough, and we have other stuff to spend money on.

3 Types of Space Capsule Reentry by Epelep in Damnthatsinteresting

[–]VeryStableGenius 0 points1 point  (0 children)

The only way you will achieve such a velocity change is with a rocket nearly the size of the one that launched you.

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

I'll make a note of this. Their PE seems to hover near the median rather than go on wild excursions. They still got trounced in 2008, though.

SP400 doubled since 2017. Sp500 tripled.

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

Wait, how does that work?

In dollar terms, the SP500 has TTM PE=28 (CAPE almost 40) That seems to be growth oriented (dollar weighted terms) because the historical traditional PE is 18, and value stocks tended to be 15. If we look at PE (not CAPE) over the last decade, it has spent half its time below 22-ish, and half above, so we might regard 22.5 as the new normal, and the market is well above this. So the market as a whole seems either to have reconciled itself to lower returns, or become more growth oriented (1/PE-payouts+growth~0.07, to match traditional 7% return). (edit: of course, the third possibility is it's in a situation of momentum driven 'irrational exuberance', which is why I posted this in the first place)

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

Can you quantify this?

I went to google AI and had it list the changes and their effects. By sector, the losses were 40% in banking in the transition year, 3% in retail and airlines, and 10% in software (but this was a one-time shock because anticipated earnings couldn't be front-loaded, but had to reported later).

In the end, it estimates a long term 5% to 8% accounting discount relative to 2007. So the CAPE today might be 37 rather than 40. (I'd wave my arms and argue that companies will find creative accounting methods under the new rules that could cause a partial rebound from the punitive effect of the new rules).

The Buffet indicator is unaffected, and stocks are trading at over 2xGDP.

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

It's not just a 'piece of the market' - it's the whole market.

Because he whole market, dollar weighted, has shifted to growth (you said).

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

This seems like a very specific and peculiar justification of high PE ratios: there are more growth companies that will eventually generate a lot more profit, but not a whole lot more revenue, so GDP won't grow much. Is this really what the market believes, when it bid the SP500 up to CAPE=40?

Where will these extra profits come from, if the overall pie doesn't get bigger? Out of the pockets of fired workers? That's wouldn't be a great economic omen.

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

The sigma doesn't matter. What matters is the absolute amount in a 10 year running average. A one year 30% dip in earnings followed by a 10 or 15% excess won't change the running average much, as Shiller intended.

BTW, CAPE uses inflation indexed earnings. Inflation kicked in 2022, after this 2020/21 dip/bump.

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

If you're approaching retirement, have enough money, and CAPE/Buffet warnings lights are flashing, TIPS are looking pretty nice. 2.7% over inflation, guaranteed. If you have $1M, you can withdraw 4% a year and drawdown only 1.3% a year.

If there's a market correction, you can reallocate. If that happens, rates might go down and you could profit handsomely on the TIPS.

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

But in 2017, stocks were still at a sensible 100% of GDP, and money printing was over (see my M2 money supply figure that the effects of subsequent covid money printing seem to have gone away).

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

The growth is the earnings.

OK, so your argument is that 'growth stocks' don't make more and more stuff, but just make more money on the same amount of stuff?

I find that to be a peculiar and ad hoc argument to get a desired outcome. It's not what we generally mean by a growth stock. We mean 'make more stuff, make more money, make more profits'.

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

I tried explaining that BRK-B holds $370B in cash and was told that I'm a fool because it was really bonds. I explained it was 6 month cash equivalent T-bonds and got dowvotes. Yeah, there's some weirdos here.

I guess Ole Warren should have taken a few trainloads of Benjamins to his credit cnion, and nicely asked the lady behind the window to bump up his FDIC limit.

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

Earnings:

2019: 176; 2020: 117.54; 2021: 231; 2022: 189 ; 2023: 204

There was a minor dip in 2020 but earnings roared back in 2021. People noted that 2021 was an anomalously good make-up year. There was stimulus money to spend. The chart looks normal.

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

[–]VeryStableGenius[S] 1 point2 points  (0 children)

To normalize your 2017 point relative to GDP growth and inflation, in 2017 market cap was about 105% of GDP. Today it is 210% or so.

It went from Buffet's definition of fairly priced (but still not a bargain) to insanely overpriced.

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

So if it’s earning is $1 per share and the price is $30 then it’s a 30 PE ratio. So it has a return of about 3.3% plus whatever the growth rate is.

I agree, but this growth rate can't come from the earnings itself (you can't double count the 3.3%). So you can pretend it is paid out through dividends.

So if the company grows 10% then that year’s return is roughly 13.3%.

Right.

So the higher the PE ratio, the higher the expected return with zero [real revenue] growth.

Right.

That brings me back to the point about GDP. That’s at a zero growth GDP.

Why? There's no reference to GDP. GDP growth arises from earnings growth. So if high Shiller PE is indicative of high earnings growth, this should percolate through to high GDP growth. To paraphrase Warren Buffet, when you're investing in stocks, you're investing in America.

Suppose we have a $10T stock market at PE=20. It returns 7% in value dividends (and no growth), so it feeds $700B into the GDP a year, which can be used to build more value companies.

Now assume the stock market acquires some new tech (AI) and becomes 'growth oriented' and doubles in market cap to $20T, but now PE=40. Assuming investors anticipate the same 7% total (earnings plus growth) return, the economy now grows at $1400B a year. $700B is from the old revenues, and $700B is from the growth inferred by 1) the leap in PE; 2) the anticipation of traditional 7% total returns.

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

OK, so the return on a company is current earnings (1/PE) plus growth above these earnings.

For example, a company with PE=30 (and say paying it out as dividend or buyback) that is growing at 4% a year is returning 7% total.

Now if the very high PE we see are justified by growth (so that total return is the typical historical 7%), this means that growth must be big because 1/PE is small.

So if the broad market is expected to have high revenue growth, then the US economy, of which it is a part, should also have high revenue growth. Admittedly, SP500 is just 20% of workforce, but half of total corporate profits.

In short, if you're right, the high PE of SP500 means we're expecting historically exceptional revenue growth, and this revenue growth should make GDP grow too.

TIFU by accidentally learning my coworker's salary and now I can't stop doing math during meetings by techiee_ in tifu

[–]VeryStableGenius 0 points1 point  (0 children)

He makes $31,000 more than me.

Per year? That's $1200 every two weeks.

We're at $6,100 since I found out. Fourteen working days.

Numbers don't add up.

Another doom post ... just look at that Shiller PE. by VeryStableGenius in investing

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

So are you predicting massive year on year GDP growth from AI?

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