Weight gain is a common complaint of holidaymakers.
According to Nasa choosing a different destination could make a difference in
how much you weigh.
Scientists have recently discovered the reason why
travellers to Sri Lanka are lighter, whereas you’ll gain weight in Turkey. It’s
not the baklava.
Since the 1960s Nasa has known that gravity does not affect
the globe evenly, with ‘anomalies’ in the weight of objects travelling from one
location to another.
Though those hoping to shed might be disappointed.
A traveller weighing 68kg in New Zealand could lose up to 3g
when in the Maldives or Canada’s Hudson Bay, where there are areas of lower
relative-gravity. The difference is not massive, around 1/25,000 of your
bodyweight, but it’s a start.
What it does tell us is that the makeup of the planet is
very different under foot, affecting the weight and gravitational force on the
surface.
Which country has lowest gravity?
Satellites from Nasa’s GRACE mission (Gravity Recovery and
Climate Experiment) have been mapping the differences for years. While ocean
measuring stations have suggested there is a difference the use of satellite
imaging to measure water density has allowed Nasa to build high definition of
gravity.
The lowest gravity on the planet is found at the southern
tip of Sri Lanka and parts of the Indian Ocean east of the Maldives. North
Canada around the Hudson Bay area is also an area of low gravity.
The difference is thought to be down to the thickness of the
Earth’s crust and the volume of molten rock and magma, beneath the surface.
“The Canadian anomaly has been known for a long time,” said
Dan Britt, director of the Center for Lunar and Asteroid Surface Science.
He described it like squishing a jam sandwich, the thick ice
sheets deformed the crust, pushing the fluid to the edges.
“A couple of miles of ice is heavy enough to depress the
crust,” said Britt.
Where on Earth is gravity the strongest?
Elsewhere ‘heavy’ spots can be explained by currents in
molten rock, or magma, and convection currents in superheated bubbling lava.
The strongest gravity earth is located around Bolivia and
the northern Andes, where relative gravity represents around 50 additional
milligals. Here you’ll be around 1/19613th heavier than at 1 standard gravity.
Objects are also slightly heavier around the poles and
around the fault lines of the Pacific. There is an area of increased weight at
the top of New Zealand’s North Island following the Kermadec Trench.
The distribution of gravity is slowly changing as the fluid
magma redistributes and continental plates shift. Since the launch of the GRACE
and GRACE-FO (follow on) satellites in 2018, Nasa has been mapping the slow
change, by measuring surface water.
Measuring “the amount of water in large lakes and rivers, as
well as changes in sea level and ocean currents provides an integrated global
view of how Earth’s water cycle and energy balance are evolving”, says the Nasa
GRACE mission.
Rather than helping weight watchers plan their holidays,
there are bigger implications of gravitational anomalies on surface water which
compound climate changes.
“GRACE allows hydrologists to monitor water in underground
aquifers and entire river basins, providing better information for decisions
about drought mitigation and flood hazards,” says the mission’s Gravity Model
from the University of Texas.
Sadly you’ll gain that weight back the moment you get home.
Source : nzherald
- Agencies
