4,808 reputation
1737
bio website
location Göttingen, Germany
age 29
visits member for 2 years, 9 months
seen 2 days ago

Postdoctoral researcher, Institut für Astrophysik Göttingen.


2h
awarded  Notable Question
2d
reviewed Approve suggested edit on Velocity required for orbit of satellite
2d
reviewed Approve suggested edit on $U(1){\times}U(1)$ local gauge invariance derivative
2d
reviewed Approve suggested edit on Gravity problem
Apr
14
comment Wouldn't angular momentum of a binary star system decrease?
It's worth noting that Hulse and Taylor won the Nobel Prize in 1993 for the discovery and analysis of this system.
Apr
3
reviewed Edit suggested edit on Heat transfer and temperature difference of 2 liquids
Apr
3
revised Heat transfer and temperature difference of 2 liquids
edited the equation using latex (and improved slightly by mod)
Mar
22
comment The age of the universe
If you're confused by why we think the Universe should be "isotropic" and "homogeneous", it might sound more convincing in simpler terms. When averaging over large enough parts, we expect the structure of the Universe to be the same no matter where we are (homogeneous) and the same no matter what direction we look (isotropic). Now, these are clearly not perfectly true: if I look towards Andromeda... well, there's Andromeda, but if I look somewhere else nearby, I see past it. But! If I look at a big enough patch of sky, it looks about the same as another big enough patch of sky.
Mar
21
comment Why does a star beyond a certain mass limit (Chandrasekhar limit) only become a black hole?
I would only add that in this case, the use of an $n=3$ polytrope is well justified, since it's what you get for electron degeneracy in the limit that all the velocities tend to the speed of light.
Mar
20
comment Mass exchange between stars
I was going to pen a new answer, but at the end of the day this is basically all there is too it, as far as conditions go. I was going to describe observed systems where this is happening, but that's not in the question. Look at references for the Roche lobe and Roche lobe overflow.
Mar
12
comment Does the sun rotate?
And coincidentally, today's Astronomy Picture of the Day shows the Sun's rotation in seven bands.
Mar
11
comment What is the percentage of stars with planetary systems
Astrobites covered a recent article on the subject. You'll find links there to other papers that estimate the frequency of planetary systems.
Mar
11
comment Does the sun rotate?
Here's a video made by a user of Helioviewer. It doesn't answer the whole question so I'll levae it as a comment. It's a movie comprising 7 days of images from the Atmospheric Imaging Assembly (AIA) aboard NASA's Solar Dynamics Observatory (SDO). From the look of the images, I think this is the 304 Å channel. The satellite is in a geosynchronous orbit, so the motion of the Sun that you see is its surface rotation.
Mar
11
awarded  Good Question
Feb
12
awarded  Enlightened
Feb
12
awarded  Nice Answer
Jan
28
reviewed Approve suggested edit on Can I excite an already unstable element for accelerated decay?
Jan
25
answered Cepheid variable light curves
Jan
25
comment Can a small change in the Earth temperature give rise to large-scale climate changes?
+1 for the quote.
Jan
25
revised What is a simple mathematical model of a star?
A few corrections and small extra details.