Recent content by CygnusX-1

Just to re-emphasize: The Milky Way is not "run-of-the-mill" for a spiral but is instead bigger, brighter, and more massive than most other spirals. Likewise, the Milky Way is bigger, brighter, and more massive than most ellipticals. Meanwhile, this story is now on the radio...

I understand your point of view but respectfully disagree with it. All galaxies, whether large or small, are galaxies, just as all dogs, whether large or small, are dogs. Suppose, for the sake of argument, that most canine mass resides in big dogs. No one would say that a big dog such as an...

Actually, the last two paragraphs of the Knowable article do answer that question: most stars are in giant galaxies like the Milky Way.

The stellar mass of M33 appears in Section 2.1 of Sellwood, Shen, and Li (2019): https://arxiv.org/abs/1902.07222 The stellar mass of the Large Magellanic Cloud is in Section 8.4 of van der Marel et al (2002): http://adsabs.harvard.edu/abs/2002AJ...124.2639V Note that these are only stellar...

The Knowable article is NOT misleading. It says that the Milky Way is far bigger, brighter, and more massive than MOST other galaxies. It does NOT say that the Milky Way is far bigger, brighter, and more massive than ALL other galaxies. If you don't understand this, read the third, fourth...

For example, Table 1 of McCall (2014) lists 59 luminous galaxies nearby, plus the Milky Way. Most are spirals; some are ellipticals; at least one is an irregular. The fifth column gives the absolute visual magnitude of each galaxy. According to his data, only 2 of these 59 galaxies are...

No, it's not misleading at all. First, even compared with other spiral galaxies, the Milky Way is above average. M33 and the Large Magellanic Cloud--which many astronomers think would be a spiral were it not for the interference of the Small Magellanic Cloud--are both lesser galaxies than the...

Our Galaxy is far bigger, brighter, and more massive than most others: Knowable Magazine Check out the amazing video, which shows all the many--more than 50!--satellite galaxies of the Milky Way burst into existence as they are discovered, year after year.

Here's the current situation regarding the Local Group. As of early 2019, the Local Group had more than 100 known members. The following galaxies ARE members of the Local Group: Sagittarius Dwarf Spheroidal (discovered in 1994; a satellite galaxy of the Milky Way) Sagittarius...

Yes. If a star truly has no elements heavier than helium, then it can't use the CNO cycle, at least not at first. From Section 2.3 of Yoon, Dierks, and Langer (2012), Astronomy and Astrophysics, 542, A113: "In metal-free massive stars, the CNO cycle cannot be activated initially. Because the...

Yes, that was Peter van de Kamp, who claimed Barnard's Star had two giant planets akin to Jupiter and Saturn. Astronomers George Gatewood and Heinrich Eichhorn later cast doubt on those planets. The story appears in chapter 5 of Ken Croswell's book Planet Quest. The full account is much too...

The planet: Distance from star: 0.4 AU (comparable to Mercury) Orbital period: 233 days (comparable to Venus) Mass: at least 3 Earth masses Temperature: -270 F (comparable to Saturn) Barnard's Star: Distance from us: 6 light-years; second closest star system to Sun after Alpha Centauri...

See The Universe at Midnight by Ken Croswell, pages 75-76, on the tired-light theory: The tired-light theory is not new. It was first proposed by maverick scientist Fritz Zwicky in 1929, a few months after Hubble discovered the distance-redshift relation. But two observations rule it...

See the feature article on oxygen-poor galaxies in the https://www.skyandtelescope.com/sky-and-telescope-magazine/inside-april-2018-issue/ issue of Sky & Telescope. The dust-to-gas ratio varies with the metallicity of a galaxy. For giant galaxies, like the Milky Way, the dust-to-gas ratio is...

Not all red dwarfs are completely convective; only those with masses below about a third solar. Also, not all red dwarfs that are completely convective destroy all of their hydrogen. However, the lowest-mass red dwarfs DO eventually exhaust all of their hydrogen. See the details for a 0.1...