If you "run the clock backwards" using the Friedmann equations, you can avoid a singularity; you just need the pressure and energy to behave in the right way when the Universe was very hot and dense. The catch is that "the right way" in this case means that ρ+3p<0; in other words, either the energy density or the pressure (or both) have to be negative. No conventional forms of matter are known that satisfy this inequality, so unless something really strange was going on in the early Universe, there must have been an initial singularity. (Or, more plausibly, there was a time in the early Universe where the spacetime curvature was sufficiently large that the laws of GR as we know them did not apply.)
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Brain drain is one of the earliest phenomena associated with globalisation, which has significant adverse effects at the local level.
The departure of skilled workers can weaken developing countries, especially smaller ones, by depriving them of important skills and workforce.
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A spacecraft is a vehicle or device designed for travel or operation outside the Earth's atmosphere, whereas a satellite is an object that orbits the Earth, the moon, or another celestial body. ... The Voyager and Pioneer spacecraft are not satellites because they are not in an orbit around any object.
<span>Water on Mars exists today almost entirely as ice, though it also exists in small quantities as vapor in the atmosphere and occasionally as low-volume liquid brines in shallow Martian soil. The only place where water ice is visible at the surface is at the north polar ice cap.</span>
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Yes, there are certain planet that are not detected even if they are large.
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- The Doppler method is the radial-velocity method, and also an indirect method finding the extra solar planets and the brown dwarfs. While the transit method is a phenomenon only the celestial bodies are directly between a large body and an observer body.
- However, the transit method of the transiting planet is low as it depends on the alignment of the three objects that are in a near perfect straight line patterns. And that of the Doppler method that it can only measure movements along that line of sight, and this depends on the estimates of inclination of the planet's orbit to determine its mass.
- <u>Thus of a planet is found by both these methods we can find its density, and an indication of its composition.</u>
