The universe’s first molecule, Helium hydride
(HeH+), has been detected in space for the first time. Previously, helium
hydride had been produced and tested in a laboratory setting.
It has been spotted some 3000 light-years from
Earth by an instrument aboard the airborne Stratospheric Observatory for
Infrared Astronomy (SOFIA). SOFIA is a Boeing 747SP aircraft modified to carry
a 2.7-meter reflecting telescope. It flies above the opaque parts of Earth’s
The molecule was found in a planetary nebula,
NGC 7027, which is the dusty remnant of a sun-like star.
HeH+, a combination of helium and hydrogen, is thought
to be created after the Big Bang. It was formed when decreasing temperatures in
the young universe allowed recombination of the light elements produced in the
The ions of the light elements viz. hydrogen,
helium, deuterium and traces of lithium produced in Big Bang nucleosynthesis
recombined in reverse order of their ionisation potential. Helium combined
first with free electrons to form the first ever neutral atom.
At that time, hydrogen was still ionised or
present in form of bare protons. Helium atoms combined with these protons into
the helium hydride ion HeH+.
With the progress of recombination, HeH+ reacted
with then neutral hydrogen and created the beginning of the formation of