[OPINION] Pay homage to our own star
The following is the 36th in a series of excerpts from Kelvin Rodolfo’s ongoing book project “Tilting at the Monster of Morong: Forays Against the Bataan Nuclear Power Plant and Global Nuclear Energy”.“
Virtually all of the energy that powers the Earth’s surface and its living cargo is solar, so let’s start exploring Earth’s surface environment and its history by paying homage to our own star. Some basic facts:
Three spheres govern the amount of solar energy received by each planet. First, the surface of the Sun, which emits an enormous amount of heat every second: 1026 calories (written, the number is a 1 followed by 26 zeros).
For reference, a calorie is the amount of heat that raises the temperature of one milliliter of water by one degree Celsius. Concretely, to bring a liter of water from room temperature to boiling requires about 75,000 calories. (It is not the diet Calorie, which is one thousand small calories, maybe so dieters don’t feel too intimidated.)
These 1026 the calories radiate into space in all directions. Reaching Earth nearly 150 million miles away, think of all that heat as having been spread out over a vast sphere in which Earth, our third sphere, sits and receives its tiny share.
We call the intensity of sunlight reaching the Earth its “solar constant”. The last image does the math: all the solar radiation divided by the area of the Sun-Earth sphere gives our solar constant, 0.033 calories per square centimeter per second.
Under this solar warming, the Earth was neither too hot nor too cold for life to begin and continue. Could the solar constants of Venus or Mars also support life now or in the past? Let’s compare them. Keeping it simple, let’s just refer to Earth’s solar constant as 100% of the solar energy it receives.
Comparison of the Earth’s solar constants with those of Venus and Mars
Mercury, the planet closest to the Sun, plays only a minor role here. It has no atmosphere, so facing the Sun at noon its temperature is 427°C. At midnight it is -173°C, horribly, inconceivably freezing. Common sense tells us that the amount and intensity of solar energy that arrives at each planet depends on its distance from the Sun. But doubling the distance doesn’t just cut the energy in half; it reduces the solar constant to 1/4e; tripling the distance reduces it to 1/9e; quadrupling it reduces it to 1/16e, etc. (Some readers may recognize this as the “inverse square of distance” rule which also governs gravitational and magnetic attractions and other forces.) This is why the solar intensity curve drops so dramatically with distance from the Sun. . Mercury receives nearly seven times more solar heat than Earth; Venus almost twice as much; and Mars just under half.
Now let’s compare the actual temperature of the inner planets. The green dots in this next diagram would be the surface temperatures of the planets if they were controlled only by their solar constants. But compare them to their real surface temperatures, red dots.
We see that the Earth would be well below the freezing point of water if its solar constant were the only controlling factor. Fortunately, our greenhouse effect comfortably keeps our true average surface temperature within the range of liquid water.
Mars has a very thin atmosphere. On its surface, it weighs only 0.65% of that of the Earth. Its small greenhouse effect warms it up a bit, but for humans, Mars would still be viciously freezing.
Venus is the real shock, hotter even than Mercury at high noon! The immediate lesson? The planets are far from passive in their response to solar heating.
Earth and Venus: ‘Twin planets?’
During my teenage years in the early 1950s, science fiction magazines published articles about Venus, the “planet of love”. One fondly remembered magazine cover featured beautiful, playful Venusian maidens scantily clad in gauzy clothing…
At the time, the stories didn’t seem too far-fetched. After all, Venus’ solar constant, only about twice our own, predicted a surface temperature of 40°C – an uncomfortable 104° Fahrenheit, yes, but still livable (if people wore gauzy clothes).
At the time, all we could see of Venus through our most powerful telescopes was the cold top of its atmosphere, white, slightly tinged with yellow. This would surely reflect some of the sunlight back into space, keeping the planet below 40°C.
We didn’t need to go to Venus to know its dimensions; astronomers have been measuring them from long distances for centuries. And in every respect, Earth and Venus are twins. Compare them:
Even the pull of gravity on Venus is only a little less than ours. A fictional Venusian girl could probably jump a little higher than one of our ballerinas of similar size and strength on Earth.
Our understanding of Venus changed dramatically in the 1960s with the onset of the Space Age. In 1962, Mariner II of the United States made the first “flyby” in front of Venus, reporting by radio that there is no magnetic field and that its surface is very hot. By 2007, four other US satellites had collected data during flybys of Venus en route to other planets.
In 1978, NASA’s Pioneer program sent four small probes through Venus’ atmosphere to the planet’s surface and placed a satellite in Venusian orbit which radioed atmospheric and surface data up to in 1992. NASA’s Magellan orbiter made accurate maps of the surface gravitational field and topography. from 1990 to 1994.
From 1961 to 1984, the Soviet Union explored Venus in a much more elaborate, stealthy and expensive way, seemingly obsessed with conquering the planet. I was reminded of this in 2022 when Russia, trying to overwhelm Ukraine, threw thousands of troops and vehicles into deadly combat, to hell with the casualties.
The USSR’s Venera program included at least 18 failed missions. But they laid many probes. Some sent back a lot of data before the tremendous heat and pressure on the planet’s surface crushed them in less than an hour.
So, after all the space missions, what do we know about Venus now? Let’s compare Earth and Venus a bit more.
The record hottest and coldest surface temperatures on Earth are 58 and -88°C. The average is 22°C, so much of Earth’s water is liquid, luckily for us.
Venus’ hellish surface temperature of 464°C is hot enough to melt tin, lead and even zinc. Outside of this heat, the volcanoes are active, inspiring this artistic landscape:
The image says nothing about the force with which Venus’ atmosphere presses down on the planet’s surface. Earth’s atmospheric pressure is 14.7 pounds per square inch, or about one kilogram per square centimeter. We don’t notice it because it is the same outside and inside our body.
But the atmosphere of Venus is 93 times more massive! To feel similar pressure on Earth, dive a mile below the surface of our ocean.
The atmospheric composition of the Earth is also very different from that of its neighbours:
Why these big differences? Life on Earth! Gaia! We will see why and how in our next foray. – Rappler.com
Born in Manila and educated at UP Diliman and the University of Southern California, Dr. Kelvin Rodolfo has taught geology and environmental science at the University of Illinois at Chicago since 1966. He is has specialized in natural hazards in the Philippines since the 1980s.
Stay tuned on Rappler for the next episode of Rodolfo’s series.
Previous pieces of Inclination to Morong’s Monster:
- [OPINION] Inclination to Morong’s Monster
- [OPINION] Mount Natib and its sisters
- [OPINION] Burn, kill, annihilate: on flows and pyroclastic surges
- [OPINION] Under the waters of Subic Bay, an ancient pyroclastic flow deposit and numerous faults
- [OPINION] Propaganda on Faults, Earthquakes and the Bataan Nuclear Power Plant
- [OPINION] Discovering the Lubao Fault
- [OPINION] The Lubao Rift at BNPP and Volcanic Threats There
- [OPINION] How the Natib volcano and its 2 sisters were born
- [OPINION] More BNPP Threats: A Megathrust Earthquake in the Manila Trench and Its Tsunamis
- [OPINION] Shoddy, shoddy, shoddy: how they built the Bataan nuclear power plant
- [OPINION] Where, oh where, would BNPP’s fuel come from?
- [OPINION] “From megatons to megawatts”: real prices and costs of nuclear energy
- [OPINION] Uranium enrichment for energy leads to enrichment for weapons
- [OPINION] Presentation of the nuclear fuel cycle
- [OPINION] On uranium mining and processing
- [OPINION] Enriching and fabricating BNPP’s uranium fuel
- [OPINION] Dismantling of BNPP and storage of the radioactive dung of the nuclear dragon
- [OPINION] So how many greenhouse gases does nuclear power actually generate?
- [OPINION] Getting closer to the atom and its nucleus that powers nuclear power plants
- [OPINION] The nucleus and isotopes: why BNPP needs uranium 235, not uranium 238
- [OPINION] What you need to know about radioactivity
- [OPINION] Uranium mining waste and the strange idea of half-life
- [OPINION] How Nuclear Power Plants Work: Morong’s Hot Monster Piss
- [OPINION] What if there was a spent fuel pool accident at the Bataan nuclear power plant?
- [OPINION] Nuclear weapons, their radiation and human health
- [OPINION] What Chernobyl Could Have Taught Us, But Wasn’t Allowed To
- [OPINION] Activating BNPP would give workers and adults living nearby cancer
- [OPINION] Enable BNPP? You could increase childhood cancers in Bataan and beyond
- [OPINION] The Hanford site: where nuclear pollution began and still reigns
- [OPINION] Enewetak, Paradise Lost: Enewetak and its people
- [OPINION] Cold War nuclear weapons testing, and the damage and waste they left behind
- [OPINION] Nuclear Weapon Tests and the Dangers of the Runit Dome
- [OPINION] The fate of Enewetak Atoll and its inhabitants after nuclear tests
- [OPINION] The long-term future of nuclear waste