Astronomy
The solar system is a gravitationally bound system consisting of the Sun and the objects that orbit it, either directly or indirectly.
- The Sun: A star at the center, containing 99.86% of the system's known mass and dominating the system gravitationally.
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Planets: Eight planets orbit the Sun:
- Inner, terrestrial planets: Mercury, Venus, Earth, and Mars.
- Outer, gas giants: Jupiter, Saturn, Uranus, and Neptune.
- Dwarf Planets: Such as Pluto, Ceres, Eris, Makemake, and Haumea.
- Other Small Bodies: Includes asteroids, comets, and trans-Neptunian objects.
- Belts and Clouds: Asteroid belt, Kuiper belt, and the Oort cloud.
The planets orbit the Sun in elliptical paths. The asteroid belt lies between Mars and Jupiter. Beyond Neptune lies the Kuiper Belt and the scattered disc. Farther out is the Oort cloud, which is believed to be the source of long-period comets.
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Astronaut footprints are still visible on the Moon due to several factors:
- Lack of Atmosphere: Unlike Earth, the Moon has virtually no atmosphere. This means there's no wind or weather to erode or disturb the footprints.
- Absence of Water: There is no liquid water on the Moon's surface to wash away or degrade the footprints.
- No Biological Activity: There are no living organisms (plants, animals, or bacteria) to disturb or decompose the footprints.
- Fine Lunar Soil: The lunar surface is covered in a fine, powdery soil called regolith. This material is easily compressed and holds its shape well, preserving the footprints.
Because of these conditions, the footprints and other traces left by astronauts during the Apollo missions could remain visible for potentially millions of years, unless disturbed by a significant event like a meteorite impact.
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To determine the suitability of an article for astronomical studies of stars, one needs to consider several factors. However, here are two highly relevant article types:
- Research Papers in Peer-Reviewed Scientific Journals:
- The Astrophysical Journal https://iopscience.iop.org/journal/0004-637X
- Astronomy & Astrophysics https://www.aanda.org/
- Monthly Notices of the Royal Astronomical Society https://academic.oup.com/mnras
- Review Articles:
- The Annual Review of Astronomy and Astrophysics https://www.annualreviews.org/journal/astro
- Review articles within the journals listed above (The Astrophysical Journal, Astronomy & Astrophysics, Monthly Notices of the Royal Astronomical Society) often provide in-depth reviews of specific topics.
These are the most suitable and reliable sources. They present original research, methodologies, data analysis, and conclusions. Examples include:
These journals have rigorous peer-review processes, ensuring the quality and validity of the research. They cover various aspects of stellar astronomy, including stellar evolution, stellar atmospheres, asteroseismology, and more.
These articles summarize the current state of knowledge on a particular topic. They are invaluable for getting an overview of a field and identifying key research areas. Examples include:
Review articles are written by experts in the field and provide a critical assessment of the existing literature.
The suitability depends on the specific needs of the study. For in-depth original research, peer-reviewed research papers are the best. For an overview of a topic, review articles are better. Articles in popular science magazines or websites may provide a general background, but they lack the rigor and detail required for serious astronomical study.