I What Does the h Subscript 70 to the Power of 3 Mean in Supernova Units?

  • I
  • Thread starter Thread starter resurgance2001
  • Start date Start date
  • Tags Tags
    Units
AI Thread Summary
The term h_70^3 in supernova rate units refers to a dimensionless number that quantifies the current rate of expansion of the universe. Specifically, it is defined as the current Hubble constant divided by 70 km/s/Mpc, raised to the third power. This notation is used to standardize measurements in cosmology, allowing for comparisons across different studies. The exponent of three indicates that the value is scaled to a volume, as it is cubed. Understanding this unit is essential for interpreting supernova rates in cosmological research.
resurgance2001
Messages
197
Reaction score
9
Hi
This is a really basic question about units. I have been reading a paper about supernova rates and the units are given as:

SN rate per yr MPC^3. h_70^3 (10^ -4)

Could someone tell me what the h subscript 70 to the power of 3 means?

Thanks
 
Space news on Phys.org
It is a dimensionless number denoting the current rate of expansion. It is equal to the current Hubble rate divided by 70 km/s/Mpc.
 
  • Like
Likes Sandip Kumar and resurgance2001
To the power of 3?
 
Thanks
 
A dimension is just another reference frame
 

Thread 'Matter density right after the decoupling'

https://en.wikipedia.org/wiki/Recombination_(cosmology) Was a matter density right after the decoupling low enough to consider the vacuum as the actual vacuum, and not the medium through which the light propagates with the speed lower than ##({\epsilon_0\mu_0})^{-1/2}##? I'm asking this in context of the calculation of the observable universe radius, where the time integral of the inverse of the scale factor is multiplied by the constant speed of light ##c##.
View full post »

Thread 'Rutgers finds a transparent Einstein Cross - apparently a dark matter "halo".'

The formal paper is here. The Rutgers University news has published a story about an image being closely examined at their New Brunswick campus. Here is an excerpt: Computer modeling of the gravitational lens by Keeton and Eid showed that the four visible foreground galaxies causing the gravitational bending couldn’t explain the details of the five-image pattern. Only with the addition of a large, invisible mass, in this case, a dark matter halo, could the model match the observations...
View full post »

Thread 'Big Bang and Infinite Universe'

Hi, I’m pretty new to cosmology and I’m trying to get my head around the Big Bang and the potential infinite extent of the universe as a whole. There’s lots of misleading info out there but this forum and a few others have helped me and I just wanted to check I have the right idea. The Big Bang was the creation of space and time. At this instant t=0 space was infinite in size but the scale factor was zero. I’m picturing it (hopefully correctly) like an excel spreadsheet with infinite...
View full post »

Similar threads

What is the problem with the units in this state equation of a gas?
Replies
12
Views
2K
B How does the cosmological constant affect gravitational collapse?
Replies
2
Views
2K
Three Phase Per Unit System - Mark up, represent as single phase equiv
Replies
0
Views
1K
The awkward expression 1 km/s per Mpc-the radius is better
Replies
12
Views
4K
What Does Unit Weight (kN/m^3) Mean?
Replies
6
Views
7K
What is the key equation for distance growth in Kindercosmos?
Replies
12
Views
2K
I I want a good reference to a discussion of the meaning of "the speed of light is constant"
2
Replies
60
Views
4K
Cosmological Constant & Fine Tuning for Life
Replies
25
Views
7K
Calculating critical density of mass, from Hubble time, for exercise
Replies
1
Views
3K
From Aeon to Zeon to Zeit, simplifying the standard cosmic model
6
Replies
277
Views
22K

Hot Threads

Recent Insights

Back
Top