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The elements Lithium, Beryllium and Boron are made by cosmic rays.


The elements Hydrogen and Helium were made during the Big Bang. Helium is also made by fusion reactions in stars.

The elements Lithium Beryllium and Boron can't be made in any quantity is stars as they are intermediate steps in other fusion reactions. Any of these elements present at the birth of a star will get consumed by later reactions.

These intermediate elements (Lithium, Beryllium and Boron) are produced by cosmic rays. These are high energy protons and other particles. These collide with nuclei of Carbon and Oxygen which breaks them down and produces Lithium, Beryllium and Boron.

Carbon is produced by reactions such as the triple Helium reaction. This reaction explains what happens to Beryllium.

#""_2^4He+""_2^4He rarr ""_4^8Be#
#""_4^8Be+""_2^4He rarr ""_6^12C#

enter image source here
The diagram shows where all of the elements are created.


#3380" N"#. Don't try this at home: you might get torn apart (see the explanation).


The amount of tension is given by the difference in gravitational force between the two masses. Let A and B be the masses, with A being closer to the black hole O. Then:



As the A and B masses are equal we substitute #M_A# for #M_B# and subtract to get the tension:


Now put in numbers and calculate:

#G=6.67xx10^{-11}" Nm"^2/"kg"^2# (same units in SI system as those given)

#M_A(=M_B)=1" kg"#, taken as exact values

#r_A=686,000-0.5=685,999.5" m"#

#r_B=686,000+0.5=686,000.5" m"#


#T=3380" N"#. This is over 170 times the gravity of Earth on the same amount of mass. A similar 100-g+ force acting on your mass would pull you apart, even though you are still relatively far from the hole's horizon.


Planets orbits are defined by conservation laws.


Johannes Kepler discovered by observation that planets follow elliptical orbits. A few decades later Isaac Newton proved that by applying the law of conservation of energy that a planet's orbit is an ellipse.

When two bodies orbit around each other, they both always orbit about the centre of mass. This centre of mass is called the barycentre. The Moon doesn't orbit around the Earth. In fact both the Earth and Moon orbit around the Earth-Moon Barycentre (EMB).

When it comes to something more complex like the solar system a similar principle applies. None of the planets etc actually orbit around the Sun. In fact the Sun, planets, asteroids, comets and other bodies all orbit around the centre of mass of the solar system which is called the Solar System Barycentre (SSB).

The SSB is in constant motion and can be anywhere from near the centre of the Sun to over a Su radius outside of the Sun. So, everything in the solar system is orbiting around a point which is in constant motion.

The diagram shows the path of the SSB over several decades. The points where the SSB is furthest from the Sun occur when the planets are aligned.

enter image source here

Question #bdf3e

Mark C.
Mark C.
Featured 4 months ago


Hmmm. That rather depends on your definition, and on how you interpret a rather troubling finding at the opposite end of physics (quantum theory.)


Firstly, let’s clarify a little. We suspect the galaxy we are in (the Milky Way) contains many (some would say many times many) intelligent life forms. The answer to this is given by solving the Drake equation and I would strongly encourage you to do this yourself (https://en.m.wikipedia.org/wiki/Drake_equation) It isn’t too scary, just guess a series of probabilities and multiply the total by the number of stars in the galaxy. Most people get between 1 and 10,000 intelligent civilisations currently existing in just our galaxy.

Next, your main question was about other universes. This is considerably more difficult to answer as, by definition, no energy (which includes information) can enter or leave our universe. That’s what ‘universe’ means. Thus we can only speculate? Well, yes and no. It all depends on how you interpret the results of a very simple, mind-blowing experiment in quantum physics called the diffraction of electrons.

In essence, a stream of electrons pass through one of two narrow slits. If you do this with light you get an interference pattern as predicted by wave theory. We do not expect that particles, like electrons would do this too, but the weirdness of that branch of physics was only just becoming apparent.

If you repeat the experiment with just one electron at a time it also builds up the same pattern over time. It’s as if either the electrons interfere with each other in the past/future or a single electron passes simultaneously through both slits. Both are impossible to our understanding of particles in space and time as we know them.

We needed a new view of very very small things and this is what quantum physics provides. Importantly, if you cover one slit the pattern disappears, and if you “peek” to see where it goes, the pattern also disappears and the electrons behave like “normal” particles, passing through one slit or other but never both.

When the “probability function” collapses to form an ‘outcome’ in our universe some propose that our universe splits into two. One where the electron went through the right hand slit, and one where it passed through the left hand slit. This implies that every event or choice in our universe causes it to split in two, yielding a ‘multiple universe’ or multiverse.

Sorry for the long, long answer .... great question :D

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