Wikipedia:Reference desk/Archives/Science/2020 May 30

= May 30 =

What if Rocket launch speed is very slow and constant?
If I walk slow, I reach destination at slow. Rocket launch speed is very slow and constant.

Will it reach the destination without obstacles? Will Escape velocity disturbs the rocket? Ram nareshji (talk) 02:30, 30 May 2020 (UTC)
 * How "slow" a rocket are you thinking of? ←Baseball Bugs What's up, Doc? carrots→ 02:36, 30 May 2020 (UTC)


 * Escape velocity decreases as you climb away from the planet. If you are able to maintain a constant speed upward then eventually you will reach a height where you are moving faster than the escape velocity for that height, which means you can leave the planet and go anywhwere.  The reason nobody does this with real rockets is that it would require huge amounts of fuel.  As you are climbing slowly, you are having to burn extra fuel to lift the extra fuel, and more fuel to lift that extra fuel, and so on.  --76.71.5.208 (talk) 03:41, 30 May 2020 (UTC)
 * Unless you have the right fuel - Grand Fenwick wine seems to do the trick... WegianWarrior (talk) 08:38, 30 May 2020 (UTC)


 * Your gravity losses would be horrendous. Fgf10 (talk) 07:49, 30 May 2020 (UTC)
 * You could very slowly ascend to some great height in the atmosphere, and then somehow accelerate up to orbital speed (most of the energy needed is in gaining tangential speed, not height). This is horribly inefficient if done with rocket fuel. Basically as a thought experiment, if you were to hover in mid air then all the fuel you use would contribute nothing towards getting you into orbit, and that's the extreme example of a slow ascent. Greglocock (talk) 20:38, 30 May 2020 (UTC)

Which first scientist declared space has Weightlessness?
Which first scientist declared space has no gravity? Ram nareshji (talk) 17:18, 30 May 2020 (UTC)
 * What does that even mean? ←Baseball Bugs What's up, Doc? carrots→ 17:25, 30 May 2020 (UTC)

Is it Isaac Newton told that space there is no gravity? Ram nareshji (talk) 17:40, 30 May 2020 (UTC)
 * I don't believe that anybody ever said that in space there is no gravity. Can you please show a reference where we can read this? If not I don't think we should try to answer such a question. In space there is gravity, as e.g. Pluto's orbit demonstrates. 2003:F5:6F08:8200:6C05:21DC:9237:7EDF (talk) 17:52, 30 May 2020 (UTC) Marco PB

I changed question now, who first told Weightlessness can observed in space ?Ram nareshji (talk) 18:00, 30 May 2020 (UTC)
 * You're not weightless in space. If you're in orbit, you're in a state of continuous free-fall. ←Baseball Bugs What's up, Doc? carrots→ 18:55, 30 May 2020 (UTC)
 * You are right of course, but in every day language we call weightlessness "the complete or near-complete absence of the sensation of weight" as one can experience in a free fall situation, like e. g. on the rollercoaster, on the Vomit Comet, in any stable orbit and exactly where the gravitational attraction between the Earth and the Moon balance each other (and ignoring the one from the Sun, Mars, Alpha centauri, Sagittarius A ...)
 * And yes, Isaac Newton is said [] to have written somewhere that objects are in free fall when they are acted upon only by gravity, so he can well have been the first physicist to mention this effect in relation to gravity, but for example some fifty years before Newton also G. Galilei was interested in free fall and could have had some idea of weightlessness. 2003:F5:6F08:8200:6C05:21DC:9237:7EDF (talk) 20:32, 30 May 2020 (UTC) Marco PB