nickjarboe
Joined 12 years ago
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134
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89
Member since
Oct 8
Recent submissions
Comment · 9 years ago
Galileo and helicopters? I think you mean Leonardo da Vinci.
Comment · 9 years ago
The Earth part was just shorthand for the fact that the atmosphere and gravity of Earth add about 1.3–1.8 km/s of delta v to achieving the pure kinetic delta v of 7.8 km/s needed to achieve LEO [1]. The first stage adds almost all of this "extra" delta v.
I was mostly just correcting your "one-sixteenth of the energy required for orbit" statement. I agree that reentering at 7.8 km/s is much more difficult than 2.0 km/s, but the second stage is smaller and more spherical than the first stage. That might make reentering it a bit easier than if it had the shape of the first stage.
Comment · 9 years ago
Nit: The energy of an object going 2,000 m/s is 1/16th of that going 8,000 m/s, but since this is a rocket launching from Earth the energy for the rocket to get to 2,000 m/s is much greater than the energy to go from 2,000 m/s to 8,000 m/s [1].
Just look at how much larger the first stage (mass almost all propellant) is compared to the second stage (large fraction of the mass is the payload).
[1] https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
Comment · 9 years ago
If the world decides to leave fiat currencies and return to gold, the value of gold will be much (10x?, 100x?) higher.
Comment · 9 years ago
I would suggest getting a "Benchmak Maps" atlas of the state you are traveling in. About $25 each. The whole state at 1:300,000 with comprehensive coverage of many features. You will find all the dirt roads and many trails. Good for driving into and around the back country. For hiking, especially off trail, I prefer good old 1:24,000 USGS maps.
Comment · 9 years ago
The records before comprehensive satellite measurements are not very useful to determine a baseline.
Comment · 9 years ago
When a city in America is destroyed by a nuclear explosion, Americans will re-learn why suburbia was so popular. Hopefully this won't happen for a long time and we will have a good stretch of city living. I love cities, but having millions of people concentrated enough to be killed by a single device; this is very different world than the one humans evolved in.
Comment · 9 years ago
Google bought WAZE in 2013. I wonder why Google Maps would be so much better than WAZE four years later.
Comment · 9 years ago
Not yet.
Comment · 9 years ago
The journal article in Nature can be found here[1]. The abstract is publicly accessible with the article behind a paywall. I'm not familiar enough with the dating method to comment on the possible problems of the age determination, but it was calculated by the complicated method of "230Th/U radiometric analysis of multiple bone specimens using diffusion–adsorption–decay dating models indicating a burial date of 130.7 ± 9.4 thousand years ago."
[1]https://www.nature.com/nature/journal/v544/n7651/full/nature...
Comment · 9 years ago
Running a rail line point to point is cheap? More like impossible.
Comment · 9 years ago
As per the article, Vanguard's biggest fund is the Vanguard Total Stock Market Index which tries to track the CRSP U.S. Total Market Index. That index is "Nearly 4,000 constituents across mega, large, small and micro capitalizations, representing nearly 100% of the U.S. investable equity market." I don't think you have to worry much about a bifurcation between large and small companies. My worry would be that the "investable equity market" is shrinking and that most the growth in the future will come from companies pre-IPO where non-accredited investors cannot invest.
Comment · 9 years ago
I think the idea behind farm to table is not that the owners of the restaurant supply everything they serve themselves but know their suppliers personally, maybe have been to the suppliers farm, and can answer detailed questions about their restaurants supply chain.
Comment · 9 years ago
Individuals buying smaller amounts of stocks may not be exercising their votes or have a board member in their back pocket, but they can in the aggregate greatly influence one thing upper management does care about: the stock's price. Unfortunately, if you think management is too focused on the short term, if everybody investing with long horizons buys mutual funds and day traders focus on individual stocks, management is likely to be even more short term focused.