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That CAN'T be true! / Re: Have you seen a Man-in-a-Hat on Mars glaring at YOU?

« on: 17/09/2020 10:21:20 »

People have seen mysterious objects on Mars for several centuries since telescopic observations of the Red Planet began. However, today scientists are skeptical about such findings, finding them quite plausible explanations.

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Physics, Astronomy & Cosmology / Re: Can light travel at a speed less than c?

« on: 08/04/2020 09:34:01 »

It is known that the maximum possible speed of movement of material objects or the propagation of any signals is the speed of light in a vacuum. It is denoted by the letter c and is almost 300 thousand kilometers per second; exact value c = 299 792 458 m / s. The speed of light in vacuum is one of the fundamental physical constants. The impossibility of achieving speeds exceeding c follows from Einstein's special theory of relativity (STR). If it were possible to prove that the transmission of signals with superluminal speed is possible, the theory of relativity would fall. So far this has not happened, despite numerous attempts to refute the ban on the existence of speeds greater than s. However, in recent experimental studies, some very interesting phenomena have been discovered that indicate that under specially created conditions superluminal speeds can be observed and the principles of the theory of relativity are not violated.

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General Science / Re: Recent Science News Stories and Science Articles

« on: 08/04/2020 09:18:16 »

The Chinese astrophysicist discovered the fastest rotating star of the Milky Way. The fastest rotating star in the Milky Way belongs to the spectral class O6.5 - these are the hot blue stars ESA / Hubble. The star LAMOST J040643.69 + 542347.8 is located in the outer arm of the Milky Way at a distance of about 30 thousand light years from the Sun, and its upper layers rotate at a record high speed - about 540 kilometers per second, which is 100 kilometers per second faster than the previous record holder HD 191423. On the results of spectroscopic observations that allow or to make this conclusion, writes astrophysicist Gangway Li in a reprint on Axis.org. Stars rotate around their axis from the moment of birth - as the gas cloud collapses into the protester, the angular momentum is conserved, which leads to rapid rotation. Gradually, this rotation slows down as a result of the interaction of the magnetic field of a star with a stellar wind, blowing away the mass. For example, a point on the equator of the Sun moves at a speed of just over two kilometers per second. However, there are stars that spin extremely fast - the fastest currently known VFTS 285 and VFTS 102 in the Large Magellanic Cloud rotate at a speed of about 610 kilometers per second. In our Galaxy, until recently, the rotation speed record belonged to HD 191423 - 435 kilometers per second. The actual rotation speed of these stars can be even greater - because we can only measure speed in projection onto the line of sight. It is not easy to make a single star spin quickly - usually  stars are in binary systems and owe high speed to their companions with whom they actively exchange matter. They can be the source of such an interesting phenomenon as long gamma's bursts. In addition, rapid rotation dramatically affects the circulation of matter inside the star. It mixes - hydrogen is transferred to the core, and the products of the  cycle - to the surface, which increases the star's lifespan and luminosity. Gangway Li calls the discovery of the fastest rotating star in the Galaxy a lucky coincidence - it was made in the process of searching for class O stars with the LAMOST spectroscopic telescope - these are hot blue stars - with emission lines of hydrogen. The spectral class LAMOST J040643.69 + 542347.8 was defined as O6.5. Unusually wide lines in the spectrum indicated a fast rotation of the star: the fact is that from the edge of a star approaching us, all lines of the spectrum shift to the blue part of the spectrum, from the moving away to the red part, and as a result of addition, the spectral lines become wider the faster they rotate star. To reliably measure the rotation speed, the author used the absorption line of ionized helium He II λ4542 - it forms deep inside the photosphere and stellar wind does not affect it anymore. It turned out that the rotation speed of the upper layers of the star in projection onto the line of sight is approximately 540 kilometers per second, which is 100 kilometers per second faster than the HD 191423 discovered in 2001. The spectrum lines of the star that rotates are wider. Rice University Some spectral lines simultaneously showed radiation and absorption: against the background of a wide emission line, a narrow absorption dip was observed. This is because the radiation and absorption of light quanta in the vicinity of the same line belong to different parts of the star. A wide emission line comes from the equatorial region with fast rotation, and a narrow absorption line from the polar regions, where gravity due to proximity to the center is stronger, density is higher, and rotation is slower than at the equator. It also turned out that LAMOST J040643.69 + 542347.8 also moves abnormally fast relative to the interstellar medium. Such stars are called runaway - and by the way, the previous record holder for rotation speed HD 191423 also refers to this type. Moreover, the fastest rotating stars known today - VFTS 285 and VFTS 102 in the Large Magellanic Cloud - are also fleeing. The magnitude LAMOST J040643.69 + 542347.8 is 13.9. This allows its further spectroscopic observations to be carried out in high resolution - LAMOST, with all its huge focal plane, has a low spectral resolution. Of particular interest, according to the author, would be to know the composition of the star's surface and compare it with HD 191423, where oversaturation with nitrogen and helium and a lack of carbon and oxygen were recorded.