Guibert Ulric Crevecoeur

10 Questions 237 Answers 0 Followers

Questions related from Guibert Ulric Crevecoeur

What occurred with the pressure and other global parameters in the universe during baryogenesis ?

The symmetry between matter and antimatter is thought to have been broken in the early universe a short time after the end of cosmological inflation (« baryogenesis »). Matter and antimatter...

14 August 2016 7,500 8 View

Why do gravitation and the electromagnetic interaction have an infinite range ?

Among the 4 elementary interactions, 2 have an infinite range : gravitation and the electromagnetic interaction. The 2 others have a very narrow range : 10-15 m for the strong interaction and...

05 May 2016 2,426 45 View

What was the value of the entropy of the Universe shortly after the Big Bang ?

It is commonly accepted that the Universe started in an ordered state with low entropy (S), which allowed its entropy to further increase - as observed - in line with the second principle of...

13 April 2016 9,040 13 View

How would alternative dark energy models plot on the conformal Hubble scale diagram ?

Plotting the conformal Hubble scale vs. the logarithmic scale factor allows to visually distinguish between dark energy physics models (e.g. for next generation measurements). The figure shows...

31 March 2016 2,458 10 View

What is the mechanism which holds dark energy present during the expansion of the Universe ?

According to measurements in the last two decades, the expansion of the Universe is accelerating (far Ia supernovae redshifts, WMAP, Planck, ...) pointing to the presence of dark energy (DE). The...

27 February 2016 7,629 5 View

What is the value of the present pressure in the universe ?

It has been deduced from WMAP and Planck observations that the expansion of the universe is accelerating. This would mean that the present pressure in the universe is negative. Do we have any...

19 February 2016 1,236 20 View

Is there a linear increase of the density of stars in the main sequence ?

Can we speak of a slight linear increase of the core density of sun-like stars during their stay in the main sequence ? As this is a period where gravitational effects are steadily balanced by the...

19 December 2015 3,533 4 View

What is the time - counted from Big Bang - of end of decoupling of photons and baryons ?

According to the Wilkinson Microwave Ansotropy Probe mission (WMAP), the time most likely for a given CMB photon to last scatter during the period of decoupling of photons and baryons is 372 000...

12 December 2015 6,445 4 View

What is the expected trend of curve for the rate of gravitational collapse of stars in function of time after stay in the main sequence ?

After stay in the main sequence, what would the rate of star heart gravitational collapse look like in function of time for : 0,1 to 8 solar mass stars (when evolving in red giants -> planetary...

27 November 2015 5,454 2 View

What is the main shape of the curve giving the rate of gravitational gas cloud collapse in function of time up to start of a main sequence star?

According to Kippenhahn's diagram, there is a decrease, but it is not clear whether this decrease has the general shape of a negative exponential or a power law or is linear or whatever...

25 November 2015 6,085 2 View