For example, the brightness of objects emitting X-rays is measured with spindle crabs.
Some journalists in Western publications, for example, when describing asteroids flying towards Earth, compare their size not only with known buildings, but also with the length or height of animals. For example, you might come across an asteroid with 30 platypuses or 20 giraffes. But astronomers also use unusual units to describe different quantities in space. For example, the brightness of X-ray emitting objects is measured in milli crabs. Laura Nicole Driessen of the University of Sydney, Australia, writes for ScienceAlert about other unusual units that scientists use to describe mass, distance, and radiation.
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Why do astronomers use unusual units of measure? According to Driessen, many space objects are too large to be described in our usual units of measurement.
Dogs that are difficult to measure
“I have a dog that is 94 cm long. The radius of the Earth in centimeters is 638 million cm, or 7.5 million dogs. And the radius of Jupiter is 85 million dogs. But it was ridiculous to use the length of dogs to describe the size of the planets. That’s why we use more meaningful units of measure,” says Driessen. .
An example of even larger measurements would be an estimate of the size of massive stars, according to the scientist. For example, the radius of the star Betelgeuse is 83,000 Earth radii or 764 Sun radii. Of course, it is much more convenient to use a comparison with the size of the Sun to describe the size of large stars.
“If we want to know the weight of an asteroid, then of course we can use a comparison with the weight of a camel, for example, we are interested in mass, not weight. In everyday life, mass and weight Likewise, but actually mass is a measure of how much an object contains. The weight of an object on Earth is, Depends on its mass and gravity. For example, my 18kg dog will be heavy on Earth but be lighter on the Moon where gravity is lower. And it’s very heavy on a planet where gravity is very large. But the mass of a dog is what it’s made of and what planet the animal is on. It doesn’t depend on it.” says Driessen.
For this reason, astronomers mainly use the mass of the Sun to measure the mass of large objects. For example, the mass of the Andromeda galaxy is 3 trillion solar masses.
“And if you measure the mass of this galaxy with the mass of my dog, it turns out that the mass of the animal is equal to the number 3 with 41 zeros,” Driessen says.
Astronomical units and parsecs
Astronomical units are used to measure distances in space. This is the distance between our planet and the Sun and is approximately 149 million km. To measure even greater distances, scientists use a unit such as the parsec (short for parallax and seconds, and these values are used in trigonometry to measure length). One parsec is about 206 astronomical units.
“It’s much easier to describe the distance between the Earth and the center of our galaxy in parsecs, not to mention kilometers. That’s 8,000 parsecs, or 1.6 million astronomical units,” Driessen says.
How is brightness measured in crabs?
An even more bizarre situation regarding units of measurement arises when scientists describe the luminosity of space objects. In the 2nd century BC, Greek astronomer Hipparchus gave the brightest stars a magnitude of 1 and the faintest stars a magnitude of 6. If we talk about the apparent size of the Sun, astronomers describe it as minus 26.
“Yes, that’s very unusual, but even more extraordinary, each magnitude value is 2.5 times different from the previous one. For example, the apparent magnitude of the star Vega is 0, but 2.5 times brighter than the star Antares. A value of 1,” says the scientist. .
But one of the weirdest units of measure is the national crab. This unit is used to measure the brightness of objects in x-ray light. “Crab” is a pulsar (a rapidly spinning neutron star) located in the center of the Crab Nebula. Scientists know the brightness of this star from X-rays, so they use the crabs to measure the brightness of other objects.
“If we’re talking about a particular object, say a binary black hole system called GX339-4, then its luminosity is one-five thousandths less than Cancer, so its luminosity is 5 millicrabs,” says Driessen.
As already written Focus, astronomers have obtained a snapshot of the collision of black holes in the early universe. It happened 3 billion years after the Big Bang.
Source: Focus
Ashley Fitzgerald is an accomplished journalist in the field of technology. She currently works as a writer at 24 news breaker. With a deep understanding of the latest technology developments, Ashley’s writing provides readers with insightful analysis and unique perspectives on the industry.