Uranus releases approximately 15% more energy than it receives from the sun, according to two new articles published in the journal Monthly opinion from the Royal Astronomical Society and the newspaper Geophysical research letters.
Composite image of Uranus. Image credit: Marcos Van Dam / WM Keck Observatory.
Uranus is unlike any other planet in our solar system. It turns on the side, which means that each post is directly facing the sun during a continuous “summer” of 42 years.
This planet also runs in the opposite direction of all planets except Venus.
The data from the NASA Uranus Flyby Voyager 2 Uranus Flyby also suggested that the planet was unusually cold inside, challenging scientists to reconsider fundamental theories of the way the planets have been formed and have evolved in our solar system.
“Since the Flyby of Voyager 2, everyone said that Uranus had no internal heat,” said Dr. Amy Simon, planetary scientist of the NASA Goddard Space Flight Center of the first article.
“But it was really difficult to explain why, especially compared to other giant planets.”
“These projections of Uranus come only one measure of the heat emitted by the planet made by Voyager 2.”
“It all depends on this data point. This is part of the problem.”
Using an advanced computer modeling technique and the decades of data, Dr. Simon and his colleagues have found that Uranus actually generates heat.
The internal heat of a planet can be calculated by comparing the amount of energy it receives from the sun to the amount of energy it releases in the space in the form of reflected light and emitted heat.
The other giant planets of the solar system – Saturn, Jupiter and Neptune – emit more heat than they receive, which means that additional heat comes from the inside, a large part of the high energy processes that formed the planets 4.5 billion years ago.
The amount of heat that a planet gives off could be an indication of its age: the less the heat released from the heat absorbed by the sun is elderly. The planet is elderly.
Uranus stood out from the other planets because he seemed to be as warm as he received, which implies that he did not have his.
These intrigued scientists. Some have hypothesized that the planet may be much older than all the others and has completely cooled.
Others proposed that a giant collision – the same which could have dropped the planet on its side – exploded the whole heat of Uranus.
But none of these hypotheses satisfied the scientists, motivating them to resolve the cold case of Uranus.
“Could we think, could it really be no internal warmth in Uranus?” said Oxford professor Patrick Irwin, principal author of the first article.
“We have done many calculations to see how much Uranus is reflected by Uranus and we realized that he was actually more reflective than people had not estimated.”
The researchers decided to determine the full budget for Uranus’s energy: how much energy it receives from the sun compared to the quantity of sun and to what extent it emits heat.
To do this, they had to estimate the total quantity of light reflected by the planet at all angles.
“You must see the light that is dispersed on the sides, not only by coming back directly,” said Dr. Simon.
To obtain the most precise estimate of Uranus’ energy budget to date, scientists have developed a computer model that has brought together everything that is known on the atmosphere of Uranus from decades of observations from ground and space telescopes, including NASA / ESA Hubble Space Telescope and the ease of NASA infrared telescope in Hawai’i.
The model included information on the hazes, clouds and seasonal changes from the planet, which all affect the way in which sunlight is reflected and how the heat escapes.
The authors found that Uranus releases approximately 15% more energy than it receives from the sun, a figure similar to an estimate of the second study.
These studies suggest that Uranus has its own warmth, although much less than its neighbor Neptune, which more emits double the energy it receives.
“Now we have to understand what this quantity of heat means in Uranus, as well as to get better measures,” said Dr. Simon.
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Patrick GJ Irwin and al. 2025. The albedo of the bolometric bond and the energy balance of Uranus. Mnra 540 (2): 1719-1729; DOI: 10.1093 / Mnras / Staf800
Xinyue Wang and al. 2025. Internal heat flow and energy imbalance of Uranus. Geophysical research letters 52 (14): E2025GL115660; DOI: 10.1029 / 2025GL115660
