1,394 reputation
1520
bio website msquant.sourceforge.net
location Århus, Denmark
age 49
visits member for 3 years, 8 months
seen 4 hours ago

(Last updated 2014-03-04.)

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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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.
Mar
14
comment Falling into Saturn or Jupiter, would we pass through it until we hit the nucleus?
@Andrew: A. Dent quote?
Jan
29
comment Relation between isophotal radius and virial radius in spiral galaxies?
@con-f-use: what is "B-band"?
Nov
25
comment Detecting dim objects
This answer could benefit from being MathJax'ed.
Nov
15
comment Why did population III stars lack planets?
If metals are initial building blocks, how could the (Pop III) stars form in the first place?
Nov
15
comment Why did population III stars lack planets?
(The Wikipedia link is a redirect. Where did you get the link? On Wikipedia itself?)
Oct
7
comment New Type of Type Ia supernova. Implications to Dark Energy measurement?
Dark energy is not a repulsive force. It's just a new (or at least different) kind of source for an old force — gravity. (From Dark Energy FAQ, near "Is it a new repulsive force?".)
Sep
16
comment Two planets in same orbit - not planets?
Exoplanetary system KOI-730 was originally thought to have co-orbital planets (in an L4/L5 configuration).