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Holger K. von Jouanne-Diedrich
Works at University of Applied Sciences Aschaffenburg
Attended University of St. Gallen
Lived in Hamburg
2,021 followers|203,650 views
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Just created this video which gives a step-by-step introduction to my OneR package (on CRAN)!

Please tell me what you think and please share - Thank you :-)

#OneR #Rpackage #rstats
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Please help me answer this question - Thank you
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Use R's powerful graphing capabilities to design and create professional-level graphics with this free title! http://bit.ly/1H2Pv1i
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Have him in circles
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There is renewed interest in my rather philosophical question from 5 years ago (I don't know how to get rid of the banner below by the way)
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Please help me answer this question - Thank you
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The brand new version v2.0 of my machine learning package OneR is on CRAN!

There are lots of new features and improvements - see the NEWS file for details: https://cran.r-project.org/web/packages/OneR/NEWS
Introduction. The following story is one of the most often told in the Data Science community: Some time ago the military built a system which aim it was to distinguish military vehicles from civilian ones. They chose a neural network approach and trained the system with pictures of tanks, ...
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Not like Earth

On Thursday, NASA will announce a planet orbiting Proxima Centauri - the star closest to our Sun, 4.24 light years away.   They're trying to make this planet sound like Earth... and that's cool.   But I'll tell you some ways it's got to be different.

Mainly, Proxima Centauri is really different from our Sun! 

It's a red dwarf.   It puts out just only 0.17% as much energy as our Sun.  So any planet with liquid water must be close to this star.

And because it's cooler than the Sun, Proxima Centauri mainly puts out infrared light - in other words, heat radiation.   Its visible luminosity is only 0.005% that of our Sun!

So if you were on a planet as warm as our Earth orbiting Proxima Centauri, it would look very dim - about 3% as bright as our Sun.

Of course, if there's life on this planet, it would probably evolve to see infrared. 

But there's a more serious problem.  Proxima Centauri sometimes puts out big flares, with lots of X-rays!  That's not very nice.

Why does a wimpy little red dwarf have bigger flares than the Sun?

The Sun has a core where fusion happens, and helium produced down in the core mainly stays there.   A red dwarf doesn't have a core: it's fully convective.  In other words, heat moves through the star not by radiation, but by hot gas actually moving up to the surface. 

All this ionized gas moving around makes big magnetic fields.  The magnetic field lines get twisted up and sometimes explode out in flares!  These flares get so hot that they emit X-rays.  That's very  hot.

The same thing happens in our Sun but on a smaller scale.  Even on a calm day, Proxima Centauri puts out as much X-ray energy as our Sun.  But when a big flare occurs, it can put out 10 times more.   This happens pretty often. 

So: any "Earth-like" planet orbiting this star will be a lot closer than the Earth is to our Sun, and get a lot more X-rays. 

Puzzle 1.  Use what I've told you to estimate how much closer a planet must be, to be at the same temperature as the Earth.

Puzzle 2.  Estimate how much more X-rays it will get.

On top of this, Proxima Centauri could be part of a triple star system!

The closest neighboring stars, Alpha Centauri A and B, orbit each other every 80 years. One is a bit bigger than the Sun, the other a bit smaller. They orbit in a fairly eccentric ellipse. At their closest, their distance is like the distance from Saturn to the Sun. At their farthest, it’s more like the distance from Pluto to the Sun.

Proxima Centauri is fairly far from both: a quarter of a light year away. That’s about 350 times the distance from Pluto to the Sun! We’re not even sure Proxima Centauri is gravitationally bound to the other stars. If it is, its orbital period could easily exceed 500,000 years.

On the bright side, Proxima Centauri will last a lot longer than our Sun. As it ages, it will get smaller and hotter, gradually changing from red to blue.  After about four trillion years it will grow to 2.5% of the Sun's luminosity.   When its hydrogen is exhausted, it will then become a white dwarf, without ever puffing out into a red giant like our Sun.

So, any planet orbiting this star will be a weirdly different world.  But if we ever get there, we could stay for trillions of years, long after our Sun has become a red giant, roasting life on Earth.

For rumors of NASA's announcement, see this:

http://phys.org/news/2016-08-scientists-unveil-earth-like-planet.html

For more on Proxima Centauri, try this:

https://en.wikipedia.org/wiki/Proxima_Centauri

#astronomy  
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Very interesting 
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Don't tell us you have not been warned...
Dozens of the nation’s most senior Republican national security officials, many of them former top aides or cabinet members for President George W. Bush, have signed a letter saying they will not vote for Mr. Trump, the Republican nominee.
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Have him in circles
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Education
  • University of St. Gallen
    Ph.D. (Dr. oec.)
  • University of Cambridge
    Certificate of Proficiency in English
  • University of Hamburg
    Master of Business Administration
Basic Information
Gender
Male
Birthday
March 29
Other names
vonjd
Story
Introduction
"Reality is that which, when you stop believing in it, doesn't go away."
Philip K. Dick

"I have always imagined that paradise will be some kind of library"
Jorge Luis Borges

If it seems too good to be true, it probably is.
Work
Occupation
Professor
Employment
  • University of Applied Sciences Aschaffenburg
    Professor, present
  • Atos
    Global Executive Director
  • Siemens
    Principal Management Consultant
  • Lufthansa
    Product Manager
  • Skandinaviska Enskilda Banken
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Map of the places this user has livedMap of the places this user has livedMap of the places this user has lived
Previously
Hamburg - Aschaffenburg - St. Gallen - London - Frankfurt - München