by Eric Mack
A star visible in an old image
seen as the bright source at the center of the square)
disappeared in a later image.
Stockholm University/Villarroel et al.
old views of the
with what we see
and find that at
least 100 stars
appear to have
or were perhaps
On March 16, 1950, astronomers at the US Naval Observatory pointed a
telescope roughly in the direction of the
the wolf, and took a picture.
When scientists look
at that same patch of sky today, something is missing, and it
could be evidence of something else lurking out there.
Back in 2016, researchers in Sweden reported that a star had
One of the roiling
distant suns visible in that
USNO image from the previous
century could no longer be seen, even with the more advanced and
sensitive digital sky surveys in use today.
The team published
a paper on the discovery, but called it "very uncertain" at the
time, resolving to do more follow-up work and to continue scouring
old USNO observations for other celestial objects that seem to have
Three years later,
it's still unclear what happened to that star spotted in 1950, but
the team behind the "Vanishing & Appearing Sources during a Century
of Observations" (VASCO)
project now says they've found a hundred more missing stars like it
by comparing old and new observations.
While they've seen
'no signs' of aliens just yet,
they say parts of space where multiple stars seem to disappear could
be the best places to look for extraterrestrial intelligence
"Unless a star
directly collapses into a black hole, there is no known physical
process by which it could physically vanish," explains a new
study published in the Astronomical Journal (The
Vanishing and Appearing Sources during a Century of Observations
Project) and led by Beatriz Villarroel of
Stockholm University and Spain's Instituto de Astrofísica
implications of finding such objects extend from traditional
astrophysics fields to the more exotic searches for evidence of
technologically advanced civilizations."
The project team
believes their search for vanishing stars could be useful in the
search for extraterrestrial intelligence (SETI)
by identifying "hot spots" in space where an unexpectedly large
number of stars seem to be missing.
"Zooming in on
the (hot spots) in our SETI (or technosignature)
searches, we can identify the most probable locations to host
extra-terrestrial intelligence," they write.
The idea here is
that a very advanced alien civilization may be able to construct a
hypothetical megastructure called a 'Dyson
sphere' that completely encompasses a star in order to
capture a large portion of its energy.
Think of it as
converting a star into a gargantuan battery.
far-fetched, but technically it would explain the sudden
disappearance of a star.
For now, though,
the hundred or so stars that have been seen going dark so far
don't appear to host aliens.
"But we are
clear that none of these events have shown any direct signs of
says co-author Martin López Corredoira in a statement.
that they are natural, if somewhat extreme, astrophysical
Alien megastructures have been
suggested as plausible explanations for other strangely behaving
stars, like with erratically dimming and brightening
Boyajian's Star, but so far other natural explanations
are more readily accepted by most scientists.
researchers hope to enlist the help of both citizen scientists and
artificial intelligence to continue examining images for possible
stars gone missing.
actually vanishing star - or a star that appears out of nowhere
- would be a precious discovery," Villarroel says, "and
certainly would include new astrophysics beyond
the one we know of today."