Related posts:

1. How Many Satellites in Space
2. How Much Does Planet Earth Weigh
3. How Many Time Zones Does Earth Have

Related posts:

1. How Many Jews Are in the World Today
2. How Much Oil Is Left In the World

We don’t know the composition of the asteroids or the objects in the Oort comet cloud or the Kuiper belt in great detail. One theory of solar system formation is that there are more metals in the inner solar system. That would mean most of the uranium is Mars, Mercury, Earth Venus and asteroid belt. There is an estimated 40 trillion tons of Uranium and 120 trillion tons of thorium in the Earth’s crust. Most of that Uranium is concentrated in the continental crust. The mantel has lower concentration of uranium, but there is a lot more mantel and mantel recycles out to crust.

The solar heavy-element abundances described above are typically measured both using spectroscopy of the Sun’s photosphere and by measuring abundances in meteorites that have never been heated to melting temperatures. These meteorites are thought to retain the composition of the protostellar Sun and thus not affected by settling of heavy elements. The two methods generally agree well.

Meteors tend to only have 0.008 ppm uranium. The Sun is 332,830 earth masses. So if the Sun was 8 ppb (parts per billion) uranium, then 0.27% of an earth mass of uranium in the Sun.

Related posts:

1. How Many Years Ago Was Earth Formed
2. How Much Does Planet Earth Weigh
3. How Much Garbage Do Humans Make a Year

Modern geologists and geophysicists accept that the age of the Earth is around 4.54 billion years (4.54 × 10⁹ years ± 1%).This age has been determined by radiometric age dating of meteorite material and is consistent with the ages of the oldest-known terrestrial and lunar samples. The Sun, by comparison, is about 4.57 billion years old, about 30 million years older.

Following the scientific revolution and the development of radiometric age dating, measurements of lead in uranium-rich minerals showed that some were in excess of a billion years old. The oldest such minerals analyzed to date – small crystals of zircon from the Jack Hills of Western Australia – are at least 4.404 billion years old. Comparing the mass and luminosity of the Sun to the multitudes of other stars, it appears that the solar system cannot be much older than those rocks. Ca-Al-rich inclusions (inclusions rich in calcium and aluminium) – the oldest known solid constituents within meteorites that are formed within the solar system – are 4.567 billion years old, giving an age for the solar system and an upper limit for the age of Earth. It is hypothesized that the accretion of Earth began soon after the formation of the Ca-Al-rich inclusions and the meteorites. Because the exact accretion time of Earth is not yet known, and the predictions from different accretion models range from a few millions up to about 100 million years, the exact age of Earth is difficult to determine. It is also difficult to determine the exact age of the oldest rocks on Earth, exposed at the surface, as they are aggregates of minerals of possibly different ages. The Acasta Gneiss of Northern Canada may be the oldest known exposed crustal rock.

Related posts:

1. How Much Uranium Is In the Solar System
2. How Many Galaxies Are There
3. How Many Satellites Are Orbiting the Earth

It would be more proper to ask, “What is the mass of planet Earth?”¹ The quick answer to that is: approximately 6,000,000,000,000 ,000,000,000,000 (6E+24) kilograms.

The interesting sub-question is, “How did anyone figure that out?” It’s not like the planet steps onto the scale each morning before it takes a shower. The measurement of the planet’s weight is derived from the gravitational attraction that the Earth has for objects near it

It turns out that any two masses have a gravitational attraction for one another. If you put two bowling balls near each other, they will attract one another gravitationally. The attraction is extremely slight, but if your instruments are sensitive enough you can measure the gravitational attraction that two bowling balls have on one another. From that measurement, you could determine the mass of the two objects. The same is true for two golf balls, but the attraction is even slighter because the amount of gravitational force depends on mass of the objects.

Newton showed that, for spherical objects, you can make the simplifying assumption that all of the object’s mass is concentrated at the center of the sphere. The following equation expresses the gravitational attraction that two spherical objects have on one another:

F = G * M1 * M2 / R²

•  R is the distance separating the two objects.
• G is a constant that is 6.67259×10^-11m³/s² kg.
• M1 and M2 are the two masses that are attracting each other.
• F is the force of attraction between them.

Assume that Earth is one of the masses (M1) and a 1-kg sphere is the other (M2). The force between them is 9.8 kg*m/s² — we can calculate this force by dropping the 1-kg sphere and measuring the acceleration that the Earth’s gravitational field applies to it (9.8 m/s²).

The radius of the Earth is 6,400,000 meters (6,999,125 yards). If you plug all of these values in and solve for M1, you find that the mass of the Earth is 6,000,000,000,000,000,000,000,000 kilograms (6E+24 kilograms / 1.3E+25 pounds).

¹ It is “more proper” to ask about mass rather than weight because weight is a force that requires a gravitational field to determine. You can take a bowling ball and weigh it on the Earth and on the moon. The weight on the moon will be one-sixth that on the Earth, but the amount of mass is the same in both places. To weigh the Earth, we would need to know in which object’s gravitational field we want to calculate the weight. The mass of the Earth, on the other hand, is a constant. 

Related posts:

1. How Much Uranium Is In the Solar System
2. How Much Does The Sun Weigh In kg
3. How Much Water is There on Earth

Occasionally a comet makes the headlines, perhaps because it is visible from Earth with the unaided eye. This gives the impression that comets are rare. However, nothing could be further from the truth. There are thought to be so many comets that even astronomers can’t count them all. Comets were born in the outer reaches of the Solar System, 4600 million years ago, when the planets were forming. Far from the Sun, they formed out of icy material as well as some rocky matter and this turned them into the ‘icebergs’ of space.
Only when a comet swings in towards the Sun does it begin to evaporate and generate the tails for which comets are so famous. Observations of Comet Halley during its last appearance in 1986 show that the top one-metre layer of the comet’s surface was lost to form the tail.

A comet probably has enough surplus ice for a few hundred passes of the Sun. After that, it may become so weakened by the loss of material that it shatters, or its surface may become so choked with tar-like substances, left behind when the ice evaporates, that it forms a layer, insulating the remaining ice from further exposure to the Sun.
If this happens it transforms into a ‘stealth’ comet! It stops producing a tail and joins the army of other near-Earth asteroids (NEAs).
Only better observations or even visits by spacecraft will tell us how many of the NEAs are really extinct comet cores.
The fact that comets die in what, astronomically speaking, is a short period of time (around 10 000 years), suggests that there must be a great reservoir of extra comets to restock them.

By studying the orbits of comets, astronomers have come to the conclusion that two such reservoirs exist. The Kuiper belt, out beyond Pluto, is a flared disc of comets that supplies most of the short-period comets (those that orbit the Sun in less than a century).
The Oort cloud (named after Jan H. Oort) is much larger and supplies the long-period comets. It encloses the Solar System, with an outer edge that reaches almost a quarter of the way to the nearest star. By taking the size of the Oort cloud into account, and the number of long-period comets that have been seen, astronomers estimate that a staggering one ‘trillion’ (12 zeros) comets may be waiting out there!

Related posts:

1. How Many Moons Does Jupiter Have
2. How Many Years Ago Was Earth Formed
3. How Many Galaxies Are There

To use a technical term, gobs. Astronomers have discovered several dozen likely “supermassive” black holes in the cores of fairly nearby galaxies, plus many more in the distant objects known as quasars. They have discovered perhaps a dozen or two likely stellar-mass black holes in the Milky Way galaxy (plus one in a satellite galaxy), and a few possible intermediate-mass black holes in the Milky Way and other galaxies. Yet these don’t even qualify as the tip of the iceberg – more like a tiny ice chip. Supermassive black holes may inhabit the cores of all galaxies with central bulges of stars, and thousands of stellar-mass black holes may inhabit the Milky Way, with thousands more in each of billions of other galaxies. One of the goals of black-hole researchers is to find as many as possible so they can estimate how common these objects are.

Related posts:

1. How Many Stars Are In The Universe
2. How Many Galaxies Are There
3. How Many Atoms Are There in The Known Universe

Our Earth feels like all there is, but we know that it’s just a tiny planet in a vast Solar System. And our Solar System is just one member of a vast Milky Way galaxy with 200 to 400 billion stars. But how many galaxies are there in the entire Universe?
This is a difficult number to know for certain, since we can only see a fraction of the Universe, even with our most powerful instruments. The most current estimates guess that there are 100 to 200 billion galaxies in the Universe, each of which has hundreds of billions of stars. A recent German supercomputer simulation put that number even higher: 500 billion. In other words, there could be a galaxy out there for every star in the Milky Way.
As was mentioned, these numbers are considered rough estimates. In order to create these estimates, astronomers use a powerful telescope, like the Hubble Space Telescope, to deeply study a region of the sky. By gathering light for hundreds of hours, Hubble is able to see more deeply than any Earth-based telescope could ever hope to look. Astronomers count up the number of galaxies in the cone of space that makes up the deep image, and then use this as an average for the rest of the sky. Even though they’re really only observed a tiny fraction of the sky at that depth, they can estimate the rest.
Most of the galaxies in the Universe are probably tiny dwarf galaxies. For example, in our Local Group of galaxies there are only 3 large spiral galaxies: the Milky Way, Andromeda, and the Triangulum Galaxy. The rest are dwarf and irregular galaxies.

Related posts:

1. How Many Stars Are In The Universe
2. How Many Black Holes Are There
3. How Many Atoms Are There in The Known Universe

The speed of light (usually denoted c) is a physical constant. Its value is exactly 299,792,458 metres per second, often approximated as 300,000 kilometres per second or 186,000 miles per second. It is the speed of electromagnetic radiation (such as radio waves, visible light, or gamma rays) in vacuum, where there are no atoms, molecules or other types of matter that can slow it down.
For much of human history, it was not known whether light was transmitted instantaneously or simply very quickly. In the 17th century, Ole Rømer first demonstrated that it travelled at a finite speed by studying the apparent motion of Jupiter’s moon Io. By 1975, the speed of light was known to be 299,792,458 m/s with a relative measurement uncertainty of 4 parts per billion. In 1983, the metre was redefined in the International System of Units (SI) as the distance travelled by light in vacuum in 1⁄299,792,458 of a second. As a result, the numerical value of c in meters per second is now fixed exactly by the definition of the meter.
According to the theory of special relativity, c connects space and time in the unified structure of space-time, and its square is the constant of proportionality between mass and energy (E = mc2). In any inertial frame of reference, independently of the relative velocity of the emitter and the observer, c is the speed of all massless particles and associated fields, including all electromagnetic radiation in free space, and it is believed to be the speed of gravity and of gravitational waves. It is an upper bound on the speed at which energy, matter, and information can travel, as surpassing it would be equivalent to travelling backwards in time. Its finite value is a limiting factor in the speed of operation of electronic devices.
The actual speed at which light propagates through transparent materials, such as glass or air, is less than c. The ratio between c and the speed v at which light travels in a material is called the refractive index n of the material (n = c / v). For example, for visible light the refractive index of glass is typically around 1.5, meaning that light in glass travels at c / 1.5 ≈ 200,000 km/s; the refractive index of air for visible light is about 1.0003, so the speed of light in air is very close to c.

Related posts:

1. How Many Galaxies Are There
2. How Many Comets Are There
3. How Many Centimeters Are In an Inch

The sun weighs 1 duodecillion kilograms (two billion billion billion tons). In pounds, it weighs 220 duodecillion. Duodecillion is the fourteenth type of number in the “illions” section of numbers “millions, billion, trillons….”

Related posts:

1. How Much Does Planet Earth Weigh
2. How Much Garbage Do Humans Make a Year
3. How Much Poop Does an Elephant Produce Per Day