Level 1 — Absolute Beginner
Mars is a planet in space. Scientists want to know what is inside it. A new study looked deep inside Mars.
The study came out on August 27, 2026. It was printed in a science magazine called Nature. The study found something scientists did not expect.
Inside Mars, the south side is much hotter than the north side. It is 200 to 400 degrees Celsius hotter. Some rock deep in the south may even be a little melted.
Alexander Berne led the study. He got his PhD at Caltech in 2026. Now he works at the University of Arizona. This discovery can help scientists learn about Mars's past, and about times when Mars may have been able to support life.
- planet
- a large round object in space that goes around a star
- deep
- far down inside something
- hotter
- having more heat than something else
- melted
- changed from solid to soft or liquid because of heat
- degrees Celsius
- a unit used to measure how hot or cold something is
- PhD
- a high degree a person earns after many years of study
- discovery
- something new that people learn or find
- life
- living things, like plants, animals, or people
Level 2 — Elementary
Mars is a rocky planet, and scientists have long wondered what its inside looks like. A new study, published in the journal Nature on August 27, 2026, gives a surprising answer.
The study found that Mars has a big and uneven hot spot deep inside it. The southern half of the planet's interior is roughly 200 to 400 degrees Celsius hotter than the northern half, and part of the southern mantle may even be partly melted rock.
Before this study, most scientists thought heat inside Mars was spread out fairly evenly between its two hemispheres, so this lopsided pattern was a real surprise. The lead researcher, Alexander Berne, earned his PhD at Caltech in 2026 and now works as a postdoctoral associate at the University of Arizona.
To see inside Mars without digging, the team used a method called tidal tomography. They studied how Mars's gravity responds, in tiny changing ways, to the pull of the Sun, and used those small changes to build a picture of the planet's interior. Scientists say this discovery opens a new window onto Mars's geologic history, including times when the planet might have had conditions able to support life.
- interior
- the inside part of something
- mantle
- the thick layer of rock inside a planet, under its surface
- molten
- melted by heat, in a liquid form
- hemisphere
- one half of a planet, divided by an imaginary line
- lopsided
- not equal on both sides
- postdoctoral
- describing research work done after finishing a PhD
- tidal tomography
- a method that studies small gravity changes to map a planet's inside
- geologic history
- the story of how a planet's rock and structure changed over time
Level 3 — Intermediate
For decades, planetary scientists have assumed that heat flows through Mars's interior in a fairly even way, distributed roughly equally between its northern and southern hemispheres. A study published in the journal Nature on August 27, 2026, overturns that assumption.
Led by Alexander Berne, who completed his PhD at the California Institute of Technology (Caltech) in 2026 and is now a postdoctoral associate at the University of Arizona, the research team found that Mars's interior is startlingly lopsided: the southern half is roughly 200 to 400 degrees Celsius hotter than the northern half, and the southern mantle may be partially molten.
The team reached this conclusion using a technique called tidal tomography, which infers a planet's internal structure from the way its gravitational response to the Sun's pull shifts subtly over time, without any need to physically probe beneath the surface.
Several explanations are under consideration for the imbalance. An ancient, giant impact could have driven heat away from the northern hemisphere long ago, the southern mantle's molten rock could be moving unevenly in a process called spontaneous convection, or thick geological features in the south could be trapping heat and slowing its escape. Whatever the cause, the discovery offers a new window into Mars's geologic history, including eras when conditions there might have been capable of supporting life, and it raises the possibility that a once hotter southern mantle gave Mars a magnetic field strong enough to produce different magnetic patterns in each hemisphere.
- assumption
- something believed to be true without full proof
- lopsided
- heavier or larger on one side than the other
- mantle
- the thick layer of rock beneath a planet's crust
- molten
- melted into a liquid state by intense heat
- tidal tomography
- a technique that maps a planet's interior from tiny changes in its gravitational response to a nearby body's pull
- convection
- the movement of heat through a fluid or semi fluid material as warmer parts rise and cooler parts sink
- geological features
- large structures in a planet's rock and landscape, such as mountains or thick crust
- magnetic field
- an invisible force produced by a planet's interior that can point a compass
Level 4 — Advanced
Planetary scientists have long treated Mars's interior as a study in symmetry, assuming that heat generated deep within the planet dissipates in roughly comparable measure across its northern and southern hemispheres. A study published in Nature on August 27, 2026, dismantles that assumption, revealing an interior far more lopsided than anyone had modeled.
The research, led by Alexander Berne, who received his PhD from the California Institute of Technology in 2026 and now holds a postdoctoral position at the University of Arizona, found that Mars's southern interior runs roughly 200 to 400 degrees Celsius hotter than its northern counterpart, and that the southern mantle may be partially molten, a state few researchers had expected to find on a planet long presumed to be geologically becalmed.
The team's tool was tidal tomography, a method that treats the Sun's gravitational tug on Mars not as a fixed quantity but as a subtly shifting one, and reads the planet's minute, time varying gravitational response as a proxy for what lies beneath its crust, obviating any need to physically sample the interior.
Three explanations are currently in contention, none yet decisive: an ancient, cataclysmic impact that could have siphoned heat away from the northern hemisphere, a pattern of spontaneous convection in which molten rock churns unevenly through the southern mantle, or thick geological structures in the south that insulate the interior and impede the escape of heat. Whichever proves correct, the finding hands researchers a fresh vantage point on Mars's geologic history, including the epochs when the planet might plausibly have harbored conditions hospitable to life, and it raises a tantalizing possibility: that a once hotter southern mantle endowed ancient Mars with a magnetic field robust enough to imprint markedly different magnetic signatures on its two hemispheres.
- symmetry
- balanced correspondence of form or structure on either side of a dividing line
- dissipates
- spreads out and gradually disappears
- lopsided
- unevenly weighted or developed on one side
- becalmed
- rendered still or inactive, without vigorous change
- proxy
- something used to represent or stand in for another thing that cannot be measured directly
- obviating
- removing the need for something
- cataclysmic
- violent and sudden, causing great change
- hospitable
- favorable to supporting living things
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