Astronomy and Astrophysics: Facts
Here is a list of some curiosities of astronomy and astrophysics. From our solar system to interstellar space.
Mercury is shrinking: It’s small, it’s hot and it’s shrinking. A NASA-funded research suggests that Mercury is still contracting today, joining Earth as a tectonically active planet.
Stellar neighbor: Proxima Centauri is a red dwarf, a small low-mass star, about 4.25 light-years (1.30 pc) from the Sun in the constellation of Centaurus. Proxima Centauri is the nearest star of the Sun that is known and at first can only be seen from the Southern Hemisphere.
A heavy star: 5 milliliters, or one teaspoon of neutron star material, equals the weight of about 900 Great Pyramids of Giza. One sugar cube equates to 100 billion tons. A cubic meter? The entire weight of the Atlantic Ocean. With an escape velocity of 100,000 km/s (Earth’s is a puny 11.3 km/s), a fall from 1 meter above a neutron star would only take one microsecond, and you would impact at around 2000 km/s, or 7.2 million kilometers per hour. This force would destroy all your component atoms, rendering all your matter identical. Fortunately, the closest neutron star is rather far away (about 400 light-years), so I wouldn’t be too concerned about the aforementioned event.
Asteroid belt: The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets. About half the mass of the belt is contained in the four largest asteroids: Ceres, Vesta, Pallas, and Hygiea. The total mass of the asteroid belt is approximately 4% that of the Moon, or 22% that of Pluto, and roughly twice that of Pluto’s moon Charon (whose diameter is 1200 km).
Sunlight Takes Around 8 Minutes To Reach Earth: The Earth is located 93 million miles (150 million kms) away from the Sun, a distance known to astronomers as an astronomical units or AU. Traveling at the speed of light (186,282 miles per second), sunlight is able to cross this vast distance in around 8 minutes 20 seconds.
Pluto is about 2,376 km in diameter. Pluto’s small size and low mass mean that it has a density of 1.86 grams per cubic centimeter according to recent measurements by New Horizons, about 40 percent of Earth’s density.
Just like black holes; neutron stars also generate gravitational waves: This year astronomers were able to detect gravitational waves originating from neutron stars. And in addition, it was possible to observe the location of the collision thanks to the efforts of the astronomers. This is a great advance for astronomy.
Most neutron stars are very fast rotators: Since the conservation of angular momentum following a supernova explosion transfers the progenitor star’s rate of rotation to the remnant that is only about 20 km (12.5 miles) in diameter, the result is that the neutron star rotates very rapidly when it is formed. Most known neutron stars rotate several hundred times per second, but the fastest rotator yet discovered, the neutron star designated PSR J1748-2446ad, is known to rotate 716 times per second, which translates into 43,000 rotations per minute, or 24% of the speed of light at the star’s equatorial surface.
Asteroid also has satellite: This color picture is made from images taken by the imaging system on the Galileo spacecraft about 14 minutes before its closest approach to asteroid 243 Ida on August 28, 1993. Ida’s moon, Dactyl, was discovered by mission member Ann Harch in images returned from Galileo. It was named after the Dactyls, creatures which inhabited Mount Ida in Greek mythology. Ida has an average diameter of 31.4 km (19.5 mi). It is irregularly shaped and elongated, and apparently composed of two large objects connected together. Its surface is one of the most heavily cratered in the Solar System, featuring a wide variety of crater sizes and ages.
Kepler-444 system: The oldest known planetary system has five terrestrial-sized planets, all in orbital resonance. This weird group showed that solar systems have formed and lived in our galaxy for nearly its entire existence. Estimated to be 11.2 billion years old (more than 80% of the age of the universe), approximately 117 light-years (36 pc) away from Earth in the constellation Lyra.
Sources: wikipedia, space.com, futurism.com and astronomytrek.com
Image credit: NASA/JPL, ESO/M. Kornmesser, NASA/XMM Newton, Casey Reed/Penn State University, NASA/ESA/Hubble
To learn more about the shrinkage of Mercury, click here.
To learn more about the gravitational waves generated by neutron stars click here.
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