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Earth is getting 50,000 tonnes lighter every year, even while 40,000 tonnes of space dust fall onto our planet’s surface during the same period. So, why are we losing so much weight? You will be surprised.
At least, I never considered this and I was surprised to hear the reasoning in More or Less, a BBC Radio 4 program about statistics and numbers. According to Dr. Chris Smith and Cambridge University physicist Dave Ansel’s calculations, despite those 40,000 tonnes of space dust that become part of our planet every year, Earth loses 50,000 tonnes of mass. Is it because we keep launching rockets? No. These are their back-of-the-napkin calculations:
- Earth gains about 40,000 tonnes of dust every year, the remnants of the formation of the solar system, which are attracted by our gravity and become part of the matter in our planet. Our planet is actually made from all that starstuff.
- NASA says that Earth gains about 160 tonnes of matter a year because the global temperature is going up: “If we are adding energy to the system, the mass must go up.” Oh, those crazy thermodynamics.
- Of course, having more people or building stuff doesn’t add any mass to the planet. Humans and things are made with the matter that is already in the planet. It’s just being transformed.
- Most of the rockets and satellites that we launch to Earth orbit eventually fall down back to Earth, so no real effect here.
- Earth’s core loses energy over time. It’s like a giant nuclear reactor that burns fuel. Less energy means less mass. 16 tonnes of that are gone every year. Not much.
- And here’s the big mass loss: about 95,000 tonnes of hydrogen and 1,600 tones of helium escape Earth every year. They are too light for gravity to keep them around, so they get lost. Gone into space.
The result: the rough estimate is -50,000 tonnes every year. Which is about 0.000000000000001 per cent less mass every year.
Should we be worried about Earth disappearing into thin air? No, you shouldn’t. And you shouldn’t worry about losing hydrogen. There’s plenty and it will take trillions of years to deplete it.
Helium, on the other hand, is a different matter. It represents 0.00052% of the volume in our atmosphere, but it’s mainly harvested from natural gas using a process called fractional distillation. Helium is becoming scarce on our planet. In fact, Cornell University physicist and Nobel Prize-winner Robert Richardson once said that each floating party balloon should have a £65 price tag.
He’s probably right, considering that it is crucial for devices like MRI scanners, where it is used for cooling superconducting magnets and growing silicon and germanium crystals as well as the production of titanium and zirconium. [Download the program here (5MB)]
Since Hydrogen and helium are both lighter then air gasses, while the earth is loosing mass, would it not be gaining weight?
losing not loosing
Erm…nope.
No. Think of it this way: If you had a full bottle of compressed helium and an empty bottle (vacuum inside), the full bottle would weigh more.
Trouble is, the whole concept of ‘weight’ gets a big screwy when you are talking about outer space.
but if where standing on a set of scales holding a large number of helium balloons, then I let them go, I would weigh more despite losing the mass of the baboons, since before I let them go the helium in the balloons is counteracting both the weight of the balloon itself and a portion of my weight. I know that I am probably looking at this all wrong. but if “he whole concept of ‘weight’ gets a big screwy when you are talking about outer space” then why did Jesus refer to weight?
Please remember the difference between Mass and Weight. Weight is Mass times the force of gravity. So think of it this way, every atom in this universe has mass. So loosing helium atoms out into space would be the same as loosing metal atoms into space(like a space craft). Its just the fact that helium is lighter than air that your statement of the human on scales is different.
Hope this makes sense.
Ok, so is Jesus wrong to say the earth is losing weight, does the earth have weight? (in terms of it’s gravitational attraction to the sun for instance)
Well in terms of gravitational attraction, this is the relationship between the suns mass and the earths mass not weight. But when you talk about things in space you typically refer to them as mass, gravity in space is rather confusing and i don’t full understand it, you start talking about Einstein’s space time field i think its called.
Im not claiming to be an expert so maybe wrong in some parts.
Can the world fall?
When all the heliums gone, can’t we just make more in a lab? Knock an electron off argon or whatever they have to do? (I made that up, I haven’t done science in years).
Probably best to work on new methodologies within the uses of helium. Any production is all about quantities and cost. But as a substance becomes rare the cost increases, so it will only be used for important things, you ain’t going to spend £1k for a balloon that makes your voice squeaky, unless you are Michael Jackson but he’s dead now – but that doesn’t mean helium or your children are safe.