Binary stars are two stars orbiting a common centre of mass. The brighter star is officially classified as the primary star, while the dimmer of the two is the secondary (classified as A and B respectively). In cases where the stars are of equal brightness, the designation given by the discoverer is respected.
Binary pairs can be classified based on their orbit. Wide binaries are stars that have orbits that keep them spread apart from one another. These stars evolve separately, with very little impact from their companions. They may have once contained a third star, which booted the distant companion outward while eventually having been ejected themselves. Close binaries, on the other hand, evolve nearby, able to transfer their mass from one to the other. The primaries of some close binaries consume the material from their companion, sometimes exerting a gravitational force strong enough to pull the smaller star in completely. The pairs can also be classified based on how they are observed, a system that has overlapping categories. Visual binaries are two stars with a wide enough separation that both can be viewed through a telescope or even with a pair of binoculars. Five to 10 percent of visible stars are visual binaries. Spectroscopic binaries appear close even when viewed through a telescope. Scientists must measure the wavelengths of the light the stars emit and determine their binary nature based on features of those measurements.
Eclipsing binaries are two stars whose orbits are at an angle so that, from Earth, one passes in front of the other, causing an eclipse. This feature is based on the line of sight rather than any particular feature of the pair.
Astrometric binaries are stars that seem to dance around an empty space; that is, their companions can not be identified but only inferred. Such a companion may be too dim to be seen or could be hidden in the glare from the primary star.
Stars referred to as double stars are two that appear close together in the sky visually but are not necessarily anywhere near one another in space.
Answer:
Lucid
Explanation:
Here, the given example is of lucid dream because Nancy already new that she was dreaming. Another characteristic of a lucid dream is that the dreamer has a certain degree of control or can gain some control over what they are dreaming like the environment, the mood or the narrative. Here, Nancy also changed her dream from bad to good by concentrating and therefore, this is clearly an example of lucid dreaming.
Answer:
The answer is eutrophication
Explanation:
Eutrophication is the process of pollution of bodies of water, such as rivers and lakes, which end up getting blurred with low levels of dissolved oxygen in the water. This causes the death of various animal and plant species, and has a very high impact on aquatic ecosystems.
These problems can directly or indirectly influence problems in the soil and air in the region.
The most important reason for the growth of labor unions in the latter half of the 19th century was poor working conditions and lack of rights for workers. Workers realized the need for organization to bring about meaningful change and formed labor unions that advocated for their rights through political engagement and negotiations with employers. The American Federation of Labor (AFL) emerged as a successful federation of unions.
The most important reason for the growth of labor unions in the latter half of the 19th century was the poor working conditions and lack of rights for workers. Workers were frustrated with their limited options for relief and the sporadic acts of protest and violence that rarely resulted in lasting change. They realized that to bring about meaningful change, they needed to organize into labor unions that could advocate for their rights through political engagement and negotiations with employers.
Groups like the National Labor Union and Knights of Labor embraced a universal approach, welcoming all wage earners regardless of gender, race, or skill level. This departure from the craft unions of the early 19th century allowed for greater unity among workers. However, the negative publicity surrounding violent labor strikes ultimately turned public opinion against these unions.
The American Federation of Labor (AFL), which was formed as a loose affiliation of different unions, emerged and grew in the wake of the universal organizations. While the AFL faced challenges due to negative publicity, it gained significant membership and was able to make progress in improving workers' rights.
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the answer is False not true