Galactic Shake-Ups
There’s still a lot we don’t know about galaxies. Just this
year, we learned our own Milky Way was shaped in large
part by a collision with the smaller Sausage galaxy about
9 billion years ago. According to papers in the Monthly
Notices of the Royal Astronomical Society and The
Astrophysical Journal Letters, the cosmic crash destroyed
the Sausage and helped create the Milky Way’s outer
fringes and central bulge.
Separate research divulged how those bulges form in
other galaxies. A galaxy’s central bump comes in one of
two types, and astronomers believed different causes
were behind them. But a June paper in Astronomy &
Astrophysics suggests both types are the result of a single
process of star formation and accumulation, which runs
faster in more massive galaxies and slower in lighter
ones. Any insights we gain into galactic evolution help us
understand what the universe will look like over time, as
well as our own galaxy’s ultimate fate.FURTHER AFIELD
Sourcing a Mystery
Thanks to a January study in Nature, we’re finally starting
to understand fast radio bursts (FRBs). Astronomers first
noticed the milliseconds-long intense pulses of radio
waves in 2006, but had learned little since. The new
research analyzed emissions from a source known as
FRB 121102 — the only known FRB that repeats — and
determined it must be near an exceptionally strong
magnetic field. Possible causes include a massive black
hole, a supernova remnant (the leftovers of an exploded
star) and a highly magnetized cloud of gas and dust.
The authors further speculated that FRB 121102 could
be a neutron star housed within one of these extreme
environments. The finding doesn’t reveal the pulses’
ultimate cause, however, so astronomers still need more
FRBs to study. Luckily, an October Nature paper described
20 new FRBs, so we may soon have even more answers.Hot Jupiter Take
Exoplanets known as ultra-hot Jupiters (because of their
extreme temperature and size) seem to lack water vapor.
Astronomers didn’t know why until an August paper
in Astronomy & Astrophysics showed that the worlds’atmospheres are just too darn hot, tearing apart any
water molecules shortly after they form. The finding
further blurs the line between exoplanets and stars.TESS Elation
The Transiting Exoplanet
Survey Satellite (TESS)
launched April 18.
Researchers hope TESSwill pick up where the dying Kepler spacecraft
left off: searching for planets outside the
solar system, including any that could prove
habitable for life.52 DISCOVERMAGAZINE.COM
FROM TOP: V. BELOKUROV (CAMBRIDGE, UK) AND JUAN CARLOS MUÑOZ/ESO; DANIELLE FUTSELAAR AND JOHN M. CHASE/SHUTTERSTOCK; NASA/JPL-CALTECH/AIX-MARSEILLE UNIVERSITY; NASASPACE