Slashdot Mirror
New, Higher Measurement of Universe's Expansion May Lead To a 'New Physics' (space.com)
doug141 writes: Astronomers have measured the universe's current expansion rate (a value known as the Hubble constant) at about 44.7 miles (71.9 kilometers) per second per megaparsec (3.26 million light-years). This is consistent with a calculation that was announced last year by a research team, but it's considerably higher than the rate that was estimated by the European Space Agency's Planck satellite mission in 2015 -- about 41.6 miles (66.9 km) per second per megaparsec. The cause of this discrepancy is unclear. "The expansion rate of the universe is now starting to be measured in different ways with such high precision that actual discrepancies may possibly point towards new physics beyond our current knowledge of the universe," a researcher said. Mike Wall writes via Space.com: "The differences in the Hubble constant estimates may reflect something that astronomers don't understand about the early universe, or something that has changed since that long-ago epoch, scientists have said. For example, it's possible that dark energy -- the mysterious force that's thought to be driving the universe's accelerating expansion -- has grown in strength over the eons, members of Riess' team said last year. The discrepancy could also indicate that dark matter -- the strange, invisible stuff that astronomers think vastly outweighs 'normal' matter throughout the universe -- has as-yet-unappreciated characteristics, or that Einstein's theory of gravity has some holes, they added."
Indeed. When I'm debugging a program and feed it new data and something completely unexpected (and obviously off-the-wall) comes out the other side, I always ask myself "Wait, what am I assuming?".
This is what drives me absolutely batshit about modern cosmology:
1) The speed of light is constant, everywhere and everywhen.
2) The gravitational constant is the same, everywhere and everywhen.
3) The shape of space is uniformly flat, everywhere and everywhen.
4) Please don't get me started about standard candles.
5) Or cosmological inflation.
6) Or the (luminiferous) aether. Sorry, the Higgs field/particle/whatever.
new data
Therefore: Dark Matter!!! Dark Energy!!! QED!
Picture a boulder embedded on a steep hillside. We say it wants to roll downhill, but it really wants to fall to the center of the earth, it's just the shape of its local space that constrains it to roll downhill. Now picture a pebble sitting on top of the boulder. It's attracted to the center of the earth, but also (yes, yes, weakly) gravitationally attracted to the center of the boulder. It wants to roll down (two!) hills. Actually, it's also attracted to the Sun, and Jupiter, and the Milky Way black hole, and Andromeda; a zillion other force vectors get simplifyingly assumed away. And we're in the position of being an ant sitting on top of the pebble, making local observations and universal assumptions.
To my way of thinking, modern cosmology has posited a spherical cow of uniform density, and is baffled about where milk comes from.