Planck Maps the Microwave Background
Image Credit:
European Space Agency,
Planck Collaboration
What is our universe made of?
To help find out, ESA launched the
Planck satellite from 2009 to 2013 to map, in unprecedented detail, slight temperature differences on the
oldest optical surface known --
the background sky when our universe first
became transparent to light.
Visible in all directions, this
cosmic microwave background
is a complex tapestry that could only show the
hot and cold patterns observed were the universe to be composed of specific
types of energy
that evolved in specific ways.
The final results,
reported last week,
confirm again that most of our universe
is mostly composed of mysterious and unfamiliar
dark energy, and that even most of the remaining matter energy is
strangely dark.
Additionally, the "final" 2018 Planck data
impressively peg
the age of the universe at about 13.8 billion years and the local
expansion rate -- called the Hubble constant -- at 67.4 (+/- 0.5) km/sec/Mpc.
Oddly, this early-universe determined
Hubble constant
is slightly lower than
that determined by other methods in the late-universe,
creating a tension that is causing much
discussion and
speculation.