1,520 reputation
1622
bio website msquant.sourceforge.net
location Århus, Denmark
age 50
visits member for 4 years, 7 months
seen Jun 29 at 17:36

(Last updated 2014-08-23.)

I am mostly interested in making scientifically important observations, like timing occultations of or by Solar System bodies and measuring variable stars.

I am also interested in citizen science projects and participate in some of them, like Galaxy Zoo.

I have been an amateur astronomer since 1975 and have worked at the European Space agency's (ESA) technical centre in Holland, ESTEC, on the ARISTOTELES mission, an earth gravity mapping mission.

Approximate coordinates: 55°20 N, 10°20 E


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Jun
20
comment Throwing a micro black hole into the sun: does it collapse into a black hole or does it result in a supernova?
Are the 7 significants digits warranted for the temperature and luminosity?
Apr
24
comment Is an H bomb a better “fusion reactor” than the Sun's core?
Despite the name, an H bomb is not really a fusion bomb, is it?
Mar
28
comment Why is the sky of the moon always dark?
How reflective is the surface (for instance, in relative terms compared to a desert on Earth)?
Feb
20
comment Why are electromagnetic waves called waves even though they don't travel through a medium?
Possible duplicate of Why don't electromagnetic waves require a medium?.
Feb
17
comment If the gravity at the center of the Earth is zero, why are heavy elements like iron there?
Where is that figure on Wikipedia?
Feb
17
comment Is there a maximum frames per second (FPS)?
That is a lot of frames!
Jan
25
comment Why do soap bubbles rise?
~4% CO2 seems a bit high (and the part of the Wikipedia article that claims it does not contain any sources). It might or might not be the number for a 20 seconds breathholding and is thus not representative.
May
23
comment How intense a magnetic field would it take to keep an hypothetical iron-made moon orbiting around it?
Wouldn't the potential energy in the magnetic system quickly be converted to heat due to hysteresis loses? Or is that only in ferrite materials or similar?
Apr
21
comment Why are sine/cosine always used to describe oscillations?
This is better than dancing hamsters :-)
Mar
9
comment How was this dot identified as a mystery planet originally (Pluto in this case)?
OK, this may not be too useful for the outer planets (Neptune is in retrograde motion 43% of the time), but couldn't the Earth's motion be compensated for?
Mar
9
comment How was this dot identified as a mystery planet originally (Pluto in this case)?
Unless near opposition (retrograde motion), the rate of apparent movement is an indication of how far out it is, right?
Feb
18
comment What is the irregularity in Uranus' orbit that is caused by Neptune?
"to affect where they are orbiting around a particular spacecraft". Don't you mean "to affect where they are orbiting around a particular planet"?
Jan
15
comment Does the Earth's rotation affect an object in the stratosphere?
I don't think removing the wind (presumably differential speed wrt. to the group below) from the equation is the same as removing the atmosphere (apparently whoosing by at 1256 km/h).
Nov
3
comment Can extra-solar gamma rays reach the Earth's surface?
The source states that the the window for indirect observations is 100 GeV to 50 TeV.
Nov
3
comment Can extra-solar gamma rays reach the Earth's surface?
Access to the book worked when I tried it today. From page 13: "The earth's atmosphere effectively blocks all electromagnetic radiation of energies greater than 10 eV. The total vertical thickness of atmosphere above sea level is 1030 g cm-2, and since the radiation length is 37.1 g cm-2, this amounts to more than 28 radiation lengths. This is true up to the energy of the highest known cosmic rays (some of which may be gamma rays)." This, I think, answers my question conclusively. May be included in the answer.
Sep
25
comment Frames of reference: Inertial and accelerated - and jerked, snapped, crackled and popped?
Rice crispies??
Dec
26
comment Detecting dim objects
@Chris White: thanks!
Jun
3
comment What are the precise statements by Shouryya Ray of particle dynamics problems posed by Newton which this news article claims have been solved?
A similar question was posed on Stack Exchange site Mathematics: Teenager solves Newton dynamics problem - where is the paper?
Apr
5
comment Mass/light ratio of galaxies
@Gigi Giles: no problem. Now to the 'accept' phase :-)
Mar
15
comment Falling into Saturn or Jupiter, would we pass through it until we hit the nucleus?
@Andrew: I think he talks about having a headache and thus not being able to enjoy to go to heaven - in the first or second episode of the original radio series.