15.43 gr

approximately 0.3 mm

0.029 grams

(Note that one mole contains Avogadro’s number of atoms, which is 6.02×1023.) So a grain of salt contains about: 5.85×10-5 gr/ (29.25 gr / 6.02×1023) = 1.2×1018 atoms, half of which are sodium atoms.

Which is bigger, an atom or a grain of sand? The atom is bigger. They are the same size.

The space between the carbon rings is only 0.14 nanometers across, which is roughly one million times smaller than the diameter of a grain of sand. Now that is small!

In each molecule of quartz we have 3 atoms (1 silicon and 2 oxygen), so this means there are roughly 2*10 19 atoms in a small grain of sand.

Assuming an average size, calculating how many grains are in a teaspoon, then multiply by all the beaches and deserts in the world, Earth has very roughly 7.5 x 10 to the 18th power grains of sand, or seven quintillion, five hundred quadrillion grains.

Stars die because they exhaust their nuclear fuel. Once there is no fuel left, the star collapses and the outer layers explode as a ‘supernova’. What’s left over after a supernova explosion is a ‘neutron star’ – the collapsed core of the star – or, if there’s sufficient mass, a black hole.

The stars with the longest lifetimes are red dwarfs; some may be nearly as old as the universe itself.

• Red Dwarf Stars. Astronomers define a red dwarf as a star having between about 0.08 and 0.5 times the mass of the sun and formed primarily of hydrogen gas.
• Luminosity and Lifetime.
• Nuclear Fusion.
• Life Cycle of Stars.

On average, a supernova will occur about once every 50 years in a galaxy the size of the Milky Way. Put another way, a star explodes every second or so somewhere in the universe, and some of those aren’t too far from Earth. But with the right amount of mass, a star can burn out in a fiery explosion.

Red stars

It has been spending its fuel so extravagantly that it cannot be older than about 10 million years. Within a million years, it is expected to go into complete collapse before probably exploding as a supernova.

The Sun as a red giant will then… go supernova? Actually, no—it doesn’t have enough mass to explode. Instead, it will lose its outer layers and condense into a white dwarf star about the same size as our planet is now. A planetary nebula is the glowing gas around a dying, Sun-like star.

1) The bigger a star is, the longer it will live. 2) The smaller a star is, the longer it will live. A smaller star has less fuel, but its rate of fusion is not as fast. Therefore, smaller stars live longer than larger stars because their rate of fuel consumption is not as rapid.

A star will spend most of its lifetime turning hydrogen into helium in its core; this nuclear reaction releases energy and makes the star shine. During this phase, a given star’s colour and magnitude remain essentially the same (we call this phase of a star’s life the main sequence phase).

On average, a supernova explosion occurs about once every hundred years in the typical galaxy. About 25 to 50 supernovae are discovered each year in other galaxies, but most are too far away to be seen without a telescope.

Molnar and his team determined that the stars would eventually collide, resulting in a kind of stellar explosion known as a “Red Nova”. Initially, they estimated this would take place between 2018 and 2020, but have since placed the date at 2022.

Stars are born when large gas clouds collapse under gravity. When it eventually dies, it will expand to a form known as a ‘red giant’ and then all the outer layers of the Sun will gradually blow out into space leaving only a small White Dwarf star behind about the size of the Earth.