Has the planet gained or lost weight over time.
Earth gains and loses mass every year but the net result is a loss. Space dust and debris constantly rains down about about the rate of 40,000 tons a year
However, about 95,000 tons of hydrogen and 1,600 tons of helium escape Earth’s gravitation pull and go into space because they are so light.
The result is a net loss of a little more than 50,000 tons a year. That is incredibly tiny in percentage terms but it is there.
There are some other small effects as well because the Earth is using energy in the core and mass = energy but the size of that effect is very small. Likewise, Global Warming is adding mass for the opposite reason but, again, the difference is too small to be important.
Gained, nothing leaves but we’re constantly being bombarded by matter at a rate of approximately 44 tons a day.
The earth is both gaining and losing mass constantly. Gases in our atmosphere (especially hydrogen and helium) escape into space. Meanwhile, cosmic dust, meteors, and comets all add mass to the earth. Overall, we lose more than we gain, so the earth is slowly losing mass.
The amount we lose is very small compared to the overall mass of the earth.
ETA: Ninja’d.
Wow, ignorance fought. I always assumed the miscellaneous space dust we accumulated would vastly outweigh (outmass?) the tiny portion of our atmosphere that escapes!
I’ m assuming that the hydrogen comes from water that is split into hydrogen/oxygen by lightning. Does this mean that the oxygen concentration in the atmosphere is increasing?
The Hydrogen is split from water by UV radiation at the fringes of the atmosphere.
I suppose that means there there is some extra free oxygen being created, but it’s a pretty small amount in the grand scheme of things.
We’ve lost the mass of a few spacecraft as well.
Where do they go?
Into space, making their way through the void. I suppose they’d probably remain in the Sun’s orbit for million of years, maybe forever.
Into space. It is that simple. It is like evaporation. Space isn’t truly empty. It has random atoms and molecules floating around in it. It isn’t important in percentage terms but the phenomenon exists.
And a fraction of the helium comes from unstable heavy elements in the crust undergoing alpha radiation and losing mass in the process. All radiation results in some lost mass, of course; it’s how unstable heavy elements transition into stable (or effectively stable) light elements. Therefore, every time an atom undergoes gamma radiation, it’s lost mass in the form of a photon, and that mass eventually makes its way into space as the Earth as a whole cools from the violent cosmic process which gave birth to our planet.
If you imagine the Earth as a massive Hot Pocket, fresh from the microwave, cool on the outside but scalding on the inside, you’re not far wrong. The difference is that Hot Pockets aren’t nearly as radioactive as the Earth, and they don’t have a molten iron core which generates a magnetic field sufficient to deflect constant charged particle bombardment. (They don’t make banana Hot Pockets, right?) Eventually, the Earth will cool to the point we no longer have a magnetic field, resulting in the solar wind stripping away our atmosphere. A few billion years after that, we fall into the Sun. Maybe the Moon will turn into a debris field and fall on us before that happens.
Just a note to observe that it is meaningless to ask about the weight of the earth. The earth creates the weight of things on earth. Mass is another matter and all the answers above are correctly in terms of mass.
I see shooting stars add to the mass of the earth, and it’s only logical that low-mass molecules escape earth’s gravity and (probably, eventually ) fall into the sun.
How do they measure the quantity?
I can’t remember, what’s the distribution for hydrogen escaping the atmosphere? Something Boltzmann related? I remember way back in physics we had to calculate the amount of hydrogen that escaped per second and it was surprisingly high when you considered it over a large time scale, but the probability of any one atom escaping at arbitrary time t was absurdly low.