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MERCURY The innermost planet of the Solar System, and also one of the four terrestrial (Meaning you can walk on the planet) planets. An inferior planet that acts as both an evening star and a morning star, but also harder to see than our planets cousin Venus. Aside from having an equatorial radius of 2,439.7 km, it also consists of 70% metallic, and silicate materials. The planet’s density is the second highest in our Solar System at 5.427 g/cm3.While the Earths high density results appreciably to Gravitational compression. Internal structure of Mercury: 1. Crust:100-300km thick 2. Mantle:600km thick 3.Core:1,800km Radius Too many words. Use keywords only please. Maximize the image. See suggested changes in the next slide.
MERCURY • Take note: • I did not cram the slide with too much info. Instead, make more slides. • I increased the image size- this makes the report more interesting. • I increased the font size- this makes it more readable (keep in mind your audience at the back of the room). • Innermost planet • One of the four terrestrial planets • Inferior planet • etc.
Surface Geology Mercury looks like the moon, showing craters and extensive mare-like plains. Since, our knowledge of Mercury is based on the old 1975 Mariner flyby and terrestrial observations, that is why it is the least understood of the four terrestrial planets. Names for Mercury come from a variety of sources. It was heavily bombarded by asteroids and comets and shortly after, it’s formation followed 4.6 billion years ago, also 3.8 billion years ago came the late heavy bombardment came. Balance this with images. Too many words! Data from the October 2008 flyby from MESSENGER gave researchers a greater appreciation for the jumbled nature of Mercury’s surface.
Impact Basins and Craters Craters of Mercury range via diameter from bowl-shaped cavities called “Impact Basins”. The largest known crater is called Coralis Basin. Having a diameter of 1,550 km. The impact that made the crater was so strong it made lava eruptions and left a concentric ring 2km around the crater. 15 craters have been spotted in Mercury. Here are some examples of craters on Mercury. Cite the sources of your images.
Plains There are only two distinct plains on Mercury. • 1. Rolling, hilly plains in the regions between craters and the oldest visible surfaces on Mercury. Inter craters appear to have destroyed earlier craters I’ll stop commenting for now, since the errors are similar for all your slides. 2. Smooth plains are widespread flat areas which cover depressions of many sizes.
Surface conditions and “atmosphere” (exosphere) The surface temp of Mercury ranges from 100K-700K because of the absence of an atmosphere and a steep temp gradient between the equator , North, and South poles. The sub solar temp during perihelion is about 700K while, it is 550K at aphelion. The daylight temp of Mercury is extremely high. Observations show that ice exists on Mercury. The floors of deep craters are not fully exposed to direct sunlight. Mercury is too hot for it to have an atmosphere. Over long times it can have an exosphere with lots of chemicals in it. The discovery of polar ice on Mercury.
Magnetic field and Magnetosphere It has a small size and a very long 59-day long rotation, it has an apparently global magnetic field. Mariner 10 made measurements and according to him ,it is 1.1% as strong as Earth. It’s magnetic field is generated by an effect called the Dynamo effect. It means that a celestial body can generate a magnetic field. This would result from the circulation of the planet’s iron-rich liquid core. Mercury’s magnetic field is strong enough to deflect the solar wind around the planet. The planets magnetic field is small enough to fit the Earth just right, it is also strong enough to trap the solar wind plasma. This graph is showing the strength of Mercury’s magnetic field.
Orbit and Rotation Mercury having the most eccentric orbit of all the planets. It’s eccentricity is 0.21with it’s distance from the Sun which is about 46 to 70 million km away. It takes about 87.969 Earth days to complete one orbit in Mercury. The planets orbit is 7 degrees inclined to the plane of the Earth’s orbit. As a result, transits of the planet across the face of the Sun only occurs when Mercury is crossing the ecliptic plane at the time it lies between the Earth and the Sun. It only occurs every 7 years (average). The planets axial tilt is only about 0.027 degrees.
Spin-orbit resonance For a lot of years now, it was thought that Mercury was tidally locked with the Sun, it rotates once every orbit and always keeping the same face directed towards the Sun. The main reason why astronomers thought it was synchronously locked with the Sun is because, whenever Mercury was best placed for observation, it was always nearly at the same point in it’s 3:2 resonance. Because of Mercury’s 3:2 spin-orbit resonance, a solar day is about 176 Earth days.