Science a GoGo's Home Page Forums General Discussion General Science Discussion Forum New Value 4 Hubble Constant

The size and age of our Universe is among the most controversial and delicate of the cosmological questions.

Infrared observations made using NASA's Spitzer Space Telescope have now given us the most precise estimate yet of the rate at which our Universe is expanding. The key was not the discovery of a new method for measuring distance. Rather, astronomers discovered how to measure brightness more accurately.
The new value for the Hubble constant, good to within three percent, is 74.3 kilometers per second per megaparsec (km/s/Mpc).

**If you are interested in the Expansion of the Universe, the stretching of light, and similar topics...I have found a very interesting article, which explains the latest measurements.

http://www.gizmag.com/hubble-spitzer-expansion-universe-redshift-cepheid/24457/

Thanks for the update.

From my calculations with this current value; the distance between the Earth and the Sun should increase 44 inches per century due to the expansion rate. Does anyone think that this value is within range of scientific measurement and verification?

I also invite anyone to verify my math on this.

Doesn't matter though, Kirby, since we are assured that the rate of expansion is insufficient to overcome the gravitational force. btw, I got a similar figure:

1.496E+08/3.086E+22 = 4.848.E-15
(1 Astronomical Unit/1 Megaparsec = 4.848.E-15)

74.3 x 4.848E-15 = 3.602E-13
(Expansion rate, km per sec, per AU = 3.602E-13)

3.602E-13 x 3.156E+09 = 1.137E-03
(Expansion rate, km per 100yrs, per AU = 1.137E-03)

After a century the Earth-Sun distance would have increased by 44.754 inches (1.13676 meters).

Thanks for the calc confirmation.

Although I doubt science’s ability to measure it at this time, I definitely believe that the data couldn’t be deciphered or extracted due to other interferences like; solar wind, Jupiter & Saturn, etc.

Basically, my premise is this: If the full might of the universe’s collective gravity can’t even show up as a slight parabolic bias against the linear expansion rate then; I don’t think that local gravities stand a chance either.

I think that, in theory at least; it should be detectable. At the very least, the “tug of war” between expansion and gravity should be theoretically detectable on a local level.

Pleased to meet you @redewenur.

May I add that you are one of my favorite people on this forum. Your balance of open mindedness in concert with adherence to rock solid principles is rare. Grounded but not tethered.

In principle it might be detectable, but right now the expansion of the solar system is so slight that you couldn't really measure it. As I understand the matter it will become a serious matter a some time far in the future. Eventually the expansion will rip individual galaxies apart, then solar systems, then planets, and eventually it will also tear up individual atoms. I think I got that from Ethan Siegal's Starts with a bang.

Bill Gill

Let me preface this by stating that my opinions and leanings are not synonymous with stubborness and can always be changed through enlightenment.

I agree with the hierarchy except for the last one (the atom).

All steps have been consistent with gravity being defeated by the expansion mechanism however: I see no signs of the expansion "trumping" any of the other tensor fields. It seems that when the universe nears zero kelvin that perhaps that could change in a snap.

I'd like to read what Siegal has to say about it. Is this on his website or is it in a book?

As I said I think I got it off of his blog. He has a lot of discussions about the Big Bang and the evolution of the universe including dark energy and dark matter. I did a quick search on his blog trying to find the part about everything eventually flying apart but I couldn't find it right off. You might have better luck. It is just a matter of figuring out the right way to word your search.

I'm one of those people with the philosophy, "If at first you don't succeed, give up".

Bill Gill