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Apr
14
comment Finding the remnants of recent supernova explosions in the solar system's neighbourhood
@all In fact now I agree with Rob Jeffries that the shock wave (shell with the mass of the star plus the one of the ambient) had to be already far away, and faint. A 2012 news explain the Local Bubble . I will give notice in my answer. Nevertheless I think that the $^{60}Fe$ can be found in the sediments of the Eltanin impact. Their description with 15-20 SN events is problematic imo, because if a few SN can 'clean' the ambient, more than a few will redistribute the mass again
Apr
13
comment Finding the remnants of recent supernova explosions in the solar system's neighbourhood
In the Local Bubble (LB) no SN remnants were found. It is impossible to consider a SN without remnants in the 'walls' of the LB. The authors are making bad science because they jumped to the preconceived solution ignoring other clues and lines of reasoning. Unless they present the remnants (they can not be invisible) they should avoid a claim as they did. A simulation do not qualify as evidence. Without remnants the probability of SN is zero. Also: from wp-near earth sn: "A supernova occurring so close would have probably caused a mass extinction, which didn't happen in that time frame".
Apr
12
revised Finding the remnants of recent supernova explosions in the solar system's neighbourhood
more info
Apr
12
answered Finding the remnants of recent supernova explosions in the solar system's neighbourhood
Apr
5
comment An argument that massive particles don't redshift?
Imo, we are comoving observers and we see the redshift.
Mar
10
comment What open-source n-body codes are available and what are their features?
I used the Gravit because it is full of options and the code is clear, but the integrator is simple and I'had implemented a Velocity Verlet one (and a Brook+ version to be aapted to opencl). It is Lua scriptable !
Feb
24
comment How is the universe flat?
flat it is: Christian Marinori and Adeline Buzzi, “A geometric measure of dark energy with pairs of galaxies,” Nature 468, 539–541 (2010), doi:10.1038/nature09577 flat it is: Planck 2013 results. XVI. Cosmological parameters
Feb
10
comment Rotational speed of a planet
This clear question was closed. It exists a formula: rot = four terms, 1st degree on three parameters that gives the rotational period of all planets from Earth to Neptune with an error less than 0.18% . Let's say it is a coincidence.
Feb
6
answered Is the Boltzmann constant really that important?
Jan
14
awarded  Yearling
Dec
21
answered How many hours will there be in a day 5,000,000,000 years from now?
Dec
12
awarded  Nice Answer
Nov
16
revised How precisely does a star collapse into a black hole?
follow up
Oct
30
revised Why don't surfboards fly out the back of a utility truck when driving on the highway?
a figure at last
Oct
30
revised Why don't surfboards fly out the back of a utility truck when driving on the highway?
An image later
Oct
30
revised Why don't surfboards fly out the back of a utility truck when driving on the highway?
An image
Oct
30
answered Why don't surfboards fly out the back of a utility truck when driving on the highway?
Oct
27
comment Earth's Kinetic energy change
I can not reconcile your graph with the one of WP, which I'm sure is correct.
Oct
26
comment Earth's Kinetic energy change
LOD IERS data 1962 2015 gives the LOD graph of WP which is not like the one of the post. What is the link to the source of your data ?
Oct
22
comment Why do we hear a higher pitched sound outside the water when we smash two stones in water?
I made an experiment at home with rocks, an audio or fft analyzer on android from google play, and I can not say that your first sentence is correct. I know that the different recipients contributed with resonances, etc. I will try at the beach, eventually. Sorry no video.