Expert: Jayendra Upadhye - 2/3/2009

Question
QUESTION: Jayen,
Is there evidence of dark energy being present anywhere other than inter-galactic space?
Thanks,
Paul

ANSWER: Hi Paul,
Dark energy has two forms.
1 - The cosmological constant.
2 - scalar fields.

The cosmological constant includes vacuum energy too.
This component of dark energy permeates all space uniformly.
So i guess that answers your question.
As it imples that dark energy is omnipresent, everywhere, at all times.
[Reminds me of the "timeless" Indian god 'Vishnu'. The name Vishnu literally means "one that permeates everything, even the atoms".
This god is always represented as a blue-black colored one, and he has names - and they are a 1000 - like "shyam" meaning "the dark one" to Krishna again meaning the dark one, but also alternatively meaning "the one that attracts"! He is the "sustainer" of the Cosmos.
His other name "Narayan" means "one who moves across waters" - waters meaning space here. He is depicted as resting in a white ocean - of milk - atop a coiled serpent. The ocean of milk is the milky way or space again.]

regards
Jayen

---------- FOLLOW-UP ----------

QUESTION: Jayen,
Thanks for the response.
My understanding is limited.  I have the impression that most of the discussion about dark energy is still theoretical, the best actual evidence being the accelerating expansion of the universe.  Have we witnessed such expansion elsewhere, such as within galaxies pushing the stars apart?  If not, why?
Thanks again,
Paul

Answer
Hi,
Much of cosmology is theoretical in its nature, as even if measurable quantities are found they are still subject to rigorous questioning.
Such as :-
1 - constancy speed of light..some people still doubt that.
2 - The value of the Hubble constant is being revised.
3 - The type-1a supernovas being standard candles

to quote some examples.
The CDMA (I think, from what i remember reading) model posits a large percentage of dark energy as the constituent of the universe.

But like you, my knowledge is also limited, I am NOT a scientist by any remote way of thinking, I am just a well read person.
May be we know more in certain areas, that's all.

regards.
Jayen