14 | New Scientist | 21/28 December 2019
A LOST town has been unearthed
in Ethiopia that belonged to the
Aksum civilisation that dominated
eastern Africa for centuries and
traded with other great powers
like the Roman Empire.
“This is one of the most
important ancient civilisations,
but people [in the Western world]
don’t know it,” says Michael
Harrower at Johns Hopkins
University in Maryland.
“Outside of Egypt and Sudan,
it’s the earliest complex society
or major civilisation in Africa.”
The Empire of Aksum controlled
east Africa and parts of Arabia from
about 80 BC to AD 825. Alongside
Rome, Persia and China, it was a
leading power of its day. Its capital,
also called Aksum, still exists.
Nobody knows how the Aksum
civilisation developed. It was
preceded by a “pre-Aksumite”
society of unknown name. This
earlier civilisation may have been
based around Yeha in northern
Ethiopia, which has the oldest
writing and standing architecture
in sub-Saharan Africa. Because of
this, Harrower and his colleagues
surveyed the surrounding area.After discussions with local
people, the researchers began
excavating a hill near a village.
They found a grid of stone walls:
the remains of buildings of a town
they have named Beta Samati,
which means “house of audience”
in the local Tigrinya language.
The find is highly significant,
says Jacke Phillips at SOAS
University of London. “Most ofour known Aksumite and pre-
Aksumite sites are old excavations,
hastily conducted and badly
published by today’s standards.”
Radiocarbon dates of the
site span from 771 BC to AD 645
(Antiquity, doi.org/dgv4). That
means Beta Samati existed
during the pre-Aksumite period
and was continuously inhabited
throughout the rise of Aksum. For
Harrower and Phillips, this implies
that pre-Aksumite settlements
weren’t abandoned when Aksum
arose, and that there may not havebeen a sharp break between the
two, as previously suspected.
Beta Samati contains many
small buildings. There is also
a large building identified as a
“basilica”. Aksum converted to
Christianity in the 4th century,
so this may have been a church.
The team found a ring (pictured)
made of copper alloy covered with
gold leaf and bearing a red stone
made of carnelian engraved with
the image of a bull’s head above a
vine or wreath. “It looks a lot like a
Roman ring, except for the style of
the bull insignia,” says Harrower.
It may be that Aksum rulers
brought in Roman craftspeople
and asked them to adapt their
designs to suit Aksum culture,
says Harrower.
Archaeologists have long known
that Aksum was a major trading
civilisation, exporting gold, ivory,
elephants and baboons.
The trade evidently reached
Beta Samati. The team found
amphorae, probably used to store
wine, which seem to come from
Aqaba in what is now Jordan,
and a glass bead probably from
the eastern Mediterranean. ❚ArchaeologyMichael MarshallI.^ DUMITRU^News
Coins and a ring found
in the Aksum town
of Beta SamatiSpace‘Grazing fireball’
skimmed Earth’s
atmosphereA SPACE rock came hurtling into
Earth’s atmosphere – and then
flew straight back out again, in a
rare example of a “grazing fireball”.
Patrick Shober at Curtin
University in Australia and his
colleagues observed the event in
July 2017 with the Desert Fireball
Network, a suite of cameras that
searches Australian skies for bright
meteors known as fireballs. They
saw an intense 1300-kilometre-long trail as the rock flew overhead
at nearly 16 kilometres per second.
“The meteoroid transited the
atmosphere for over 90 seconds
and reached a minimum height
of 58.5 km before returning
to interplanetary space,” the
researchers write in their paper.
They estimate the rock was
30 centimetres across and
weighed at least 60 kilograms.
A handful of such events have
been seen before, with the first
recorded in 1972. The 2017 event
was notable for its low altitude and
because the encounter dramatically
changed the rock’s orbit.Although the rock slowed by
about 1.5 kilometres per second as
it passed through our atmosphere,
it got a gravitational slingshot from
Earth as it left – space probes use a
similar technique to obtain a speed
boost. This means that, having
started in the asteroid belt between
Mars and Jupiter, the rock is now
likely to travel out as far as Jupiter
before heading back to go round the
sun (arxiv.org/abs/1912.01895).Shober and his team predict
it will remain in this new orbit for
200,000 years, before probably
being pushed further out, towards
Neptune, or ejected from the solar
system. “This one really was quite
unusual,” says Peter Brown at
Western University in Canada.
As well as being exotic, these
events have scientific value too.
By studying such space rocks
before and after, we can observe
how they withstand the pressures
of our atmosphere. “It’s an exquisite
experiment in seeing how strong
these objects are,” says Brown. ❚
Jonathan O’CallaghanEthiopia’s lost city
Ancient town uncovered from an empire that rivalled Rome
16
Speed of the fireball in
kilometres per second