A coffin-shaped iceberg drifting away from Antarctica is set to melt, with NASA experts saying the large chunk of ice is moving into an "iceberg graveyard".
The iceberg, known as B-15T to scientists, was snapped from the International Space Station on September 23, 2018.
Researchers have been tracking the iceberg's path, observing it gradually moving into warmer waters after 18 years adrift.
In an Earth Observatory blog post this week, NASA science writer Kathryn Hansen said the iceberg had entered a region of warm waters "where Antarctic icebergs go to die".
NASA predicts the berg will melt rapidly as it heads further north.
How B-15T got its shape
B-15T originated from B-15, its parent berg, which broke away from the Ross Ice Shelf in March 2000.
This mega iceberg measured more than 370 kilometres long and 40km wide, with NASA roughly equating its area to the state of Connecticut.
B-15's many collisions with other icebergs, and the Ross Ice Shelf itself, caused it to break down into smaller pieces.
These crashes can have enough force to abruptly fracture the crystalline ice in a way that produces linear edges, NASA glaciologist Chris Shuman said.
It is these kinds of collisions that resulted in the rectangular iceberg spotted near the Larsen C shelf by scientist Jeremy Harbeck during an aerial police ice survey last month.
"This fracturing is akin to 'cleaving' a mineral crystal with a sharp tap of [a] hammer," Dr Shuman said.
"The coffin shape is an accident of time and space, given the approximately 18.5-year voyage of B-15T.
"We can only guess at the forces that have acted on this remnant of B-15 along the long way around Antarctica."
Many of the bergs which broke off from B-15 circled Antarctica in a counter-clockwise direction on the Antarctic Coastal Current.
Satellite images from October 2017 show B-15T had been sent in a northern direction by the Weddell Sea, drifting a few hundred kilometres north-east from the tip of the Antarctic Peninsula, near Elephant Island.
It was then carried in an easterly direction on the Antarctic Circumpolar Current to its current position at a latitude of 54 degrees south.
NASA experts say the waters at this location are likely to have been warmed by an increase in sunlight, which will spell B-15T's demise.
