Average density
3 109 kg/m3
Figure 20.14 Sirius B (the speck of light at right) is a white-dwarf star, a companion to the much larger and brighter star Sirius A.
The average density of a supermassive black hole can be very low, and may actually be lower than the density of air. This is because the Schwarzschild radius is directly proportional to mass, while density is inversely proportional to the volume.
The average density of Earth is 5,515 kg/m3, making it the densest planet in the Solar system. Since the average density of surface material is around 3000 kg/m3, this indicates that denser materials exist within the core.
The average density of the universe needed to make its curvature flat.
Critical Point
The temperature and pressure at which vapor and liquid phases of a material have the same density.
Planet Average Density (gm/cm3) Required Mass for 70 cm3 (gm)
Mercury
5.4
378.0 ...
Pluto's average density lies between 1.8 and 2.1 grams per cubic centimeter. It is concluded that Pluto is 50% to 75% rock mixed with ices. Charon's density is 1.2 to 1.3 g/cm3, indicating it contains little rock.
The minimum average density that matter in the universe would need in order for its gravitational pull to slow the universe's expansion to a halt.
Dark Matter ...
where n is the average density of galaxies per unit volume. A positive value of (r) thus indicates that there are more pairs of galaxies with a separation r than would occur at random; galaxies are then said to be clustered on the scale r.
The Earth has an average density of 5520 kg/m3 (water has a density of 1027 kg/m3). Earth is the densest planet in our Solar System.
Depending on the average density of matter and energy in the universe, it will either keep on expanding forever or it will be gravitationally slowed down and will eventually collapse back on itself in a "Big Crunch".
The ratio of the average density of mass in the Universe to the critical mass density, the latter being the density of mass needed to eventually halt the outward expansion of the Universe.
The mean or average density is the total mass of a region divided by the total volume of that region.
alcator scaling (Plasma Physics and Fusion Energy Glossary) A proposed empirical law in which the energy confinement time is proportional to the product of the average density and the square of the plasma radius.
Therefore, the distribution function evaluated at such a point is the number or average density of particles per cubic length and cubic velocity that have the position and the velocity which is represented by the point.
Silicate rock has density = 3 (less than the average density of a terrestrial planet) and iron has a density = 7.8 (more than the average density of a terrestrial planet).
The rocks of the lithosphere have an average density of 2.7 and are almost entirely made up of 11 elements, which together account for about 99.5% of its mass.
At the orbit of the Earth, the solar wind has an average density of about 6 ions/cm3, compared to 2.5 1019 molecules/cm3 in the Earth's sea-level atmosphere; it is more rarefied than the best laboratory vacuum.
In fact, Saturn has the lowest average density of all of the planets. You may have seen cartoons in elementary school science books showing Saturn sitting in a bathtub of water, not because it needs to wash behind its ears, ...
For this to occur, the average density of matter in the universe has to be sufficient so that the overall spatial curvature of the universe is positive, like the surface of a sphere.
Count the number of galaxies in some large, representative spatial volume, compute the mass of all their stars and gas, take that total mass and divide by the volume and from that determine the average density of matter in that volume and, ...
Surrounding and stretching between galaxies, there is a rarefied plasma[15][16] that is thought to possess a cosmic filamentary structure[17] and that is slightly denser than the average density in the universe.
They contain much of the mass of the interstellar medium, are some 150 light-years across, and have an average density of 100 to 300 molecules per cubic centimetre and an internal temperature of only 7 to 15 K.
The optical depth, which is a measure of the average density of the rings, is defined as the natural logarithm of the ratio of the incident intensity of light of a specified wavelength to the emergent intensity, ...
Because Saturn is actually quite large for its mass, the planet has has the lowest average density of Sol's planets and would float in a large enough body of water because it has only seven tenths of water's density.
(Current best estimates are that Pluto's mass is about 3/1000th that of the Earth.) From knowing the mass and the diameter, Pluto's average density (mass per unit volume) can be calculated, giving us a due to what this remote world is made of.
Its average density is 5.2 g/cc, which is slightly less than that of the Earth or Mercury, but suggests a dense iron core and internal structure similar to that of the Earth.
So the average density of the Sun is not all that different from you. (You are about equal to water as evidenced by the fact that the human body is nearly neutrally buoyant in water; you float but not well enough to keep your nose out of the water.
Critical Density - The value that the average density of the Universe must equal or exceed if the universe is closed. If the density of the Universe is less than the critical density, the Universe will continue to expand forever ...
4 Vesta has a basaltic surface composition and an average density not much less than that of Mars. Evidently lava once flowed here indicating that the interior was at one time molten, heated by short-lived radio-isotopes.
The ground-based array indicates that the cosmic ray density in M82 is a staggering 500 times more than the average density in our own Milky Way Galaxy.
The universe's geometry is determined by the average density of everything in it - a function of the mass. There is one magic number, called the "critical density" which is represented by ρc, that determines which fate the universe will take.
There were 2,204 housing units at an average density of 439.8/sq mi (169.9/kmē). The racial makeup of the town was 42.86% White, 55.23% African American, 0.20% Native American, 0.63% Asian, 0.02% Pacific Islander, 0.44% from other races ...
of cosmology) - A theory of cosmology which proposes that the universe has existed and will exist forever in its current form. The observed expansion of the universe being caused by the continuous creation of new matter so that the average density ...
If the cosmic rays have stayed in the Galaxy, the amount of matter that they have passed through divided by the average density of interstellar space (about one atom per cubic centimeter) gives the "age" of cosmic rays.
This structure makes them especially vulnerable to tidal forces. The density of asteroids varies widely, so we'll assume an average density of 3.00. Most asteroids are structurally intact, giving them breakup resistance to tidal forces.
The density of the material composing the sun is about one fourth that of the earth; compared with water, the sun's average density is 1.41.
The discovery of these moons is important because it enables an accurate determination of the parent asteroid's mass and average density. The density then gives a clue to the asteroid's makeup - either in terms of composition or of structure.
Rasalgethi (which began life near 8 solar masses) is now in the process of removing its outer layers as it prepares to become a solar mass white dwarf like Sirius B (a star shrunk to the size of Earth with an average density of a ton in a sugar ...
Roberts concluded in this way that the average density of the Algol variables and their eclipsing companions is about one-eighth that of the sun. For (3 Lyrae G. W.
 See also: Density, Light, Sun, Distance, Earth
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