Big Bang News

1687 K (melting point of silicon)

5800 K (solar photosphere i.e. Sun's visible surface, slightly hotter than Earth's core)

28,000 K (lightning strike)

15,000,000 K (15 million K, solar core)

300,000,000 K (300 million K, thermonuclear bomb)

100,000,000,000 K (100 billion K, supernova)

Other

Mars

Europa

Titan

Enceladus

Venus

K2-18 b

Earth

The Big Bang

Ceres

Pluto/Charon

Triton

Luna (presumably in a shaded crater/magma tube)

Pluto

Charon

TRAPPIST-1d

Proxima Centauri b

YES

YES

It has or may continue to vary over time at times after the first 1 billion years after the Big Bang

It varied over time during the first 1 billion years after the Big Bang

YES

Systematic errors in stellar abundance observations

Varying fundamental constants

Stellar depletion (astrophysical solution)

Nuclear physics: Unknown/revised BBN reaction rates

Sterile neutrinos

Inhomogeneous cosmology