SUn and Planets

• The Sun is the only star in our solar system.
• The Sun's gravity holds the solar system together.
• The Sun is made of super-hot, electrically charged gas called plasma.
• The photosphere is the surface of the Sun that we see from Earth.
• Above the Sun's surface are its thin chromosphere and the huge corona (crown), where we see its features - solar prominences, flares, and coronal mass ejections.
• Several spacecraft are currently investigating the Sun: Parker Solar Probe, STEREO, Solar Orbiter, SOHO, Solar Dynamics Observatory Hinode, IRIS, and Wind.
• Sunspots are cooler and darker than the rest of the Sun's surface and are marked by intense magnetic activity.
• Solar prominences are plasma loops that connect two sunspots.
• Solar flares and coronal mass ejections are eruptions of highly energetic particles from the Sun's surface.
• The sun's composition by number of atoms is 91.0% hydrogen and 8.9% helium.
• The sun's composition by mass is 70.6% hydrogen and 27.4% helium.
• Mercury is the smallest planet in our solar system.
• Mercury is the planet nearest to the Sun, so day temperatures can reach highs of 430°C.
• The surface temperatures of Mercury are both extremely hot and cold.
• Without an atmosphere to retain that heat at night, temperatures on Mercury can dip as low as -180°C.
• Mercury is the fastest planet, revolving around the Sun every 88 Earth days.
• The environment of Mercury is not conducive to life: the temperatures and solar radiation that are distinct to this planet are presumably too extreme for organisms to adapt to.
• Mercury formed about 4.5 billion years ago when gravity pulled swirling gas and dust together to form this small planet.
• Mercury has a central core, a rocky mantle, and a solid crust.
• Mercury possesses a thin exosphere made up of atoms such as oxygen, sodium, Hydrogen, helium, and potassium.
• Venus is often referred to as Earth's twin due to its similar size and density.
• Venus has a thick, toxic atmosphere filled with carbon dioxide and is constantly shrouded in thick, yellowish clouds of sulfuric acid that trap heat, causing a runaway greenhouse effect which makes Venus roughly 390°C hotter than it would be without a greenhouse effect.
• Surface temperatures on Venus are about 475 °C-hot enough to melt lead.
• The surface of Venus is a rusty color, scattered with intensely crunched mountains and thousands of large volcanoes.
• Venus has crushing air pressure at its surface.
• Venus rotates on its axis backward, compared to most of the other planets in the solar system.
• Soviet spacecraft made the most successful landings on the surface of Venus to date, but they didn't survive long due to the extreme heat and crushing pressure.
• NASA's Parker Solar Probe has made multiple flybys of Venus.
• Venus was the first planet to be explored by a spacecraft.
• NASA's Mariner 2 is the first spacecraft successfully flew by and scanned the cloud-covered world on Dec 14, 1962.
• NASA's Juno spacecraft is currently in orbit around Jupiter and has made multiple flybys of Venus.
• NASA's Magellan successfully mapped the planet's surface of Venus with radar.
• On Feb 9, 2022, NASA announced the spacecraft had captured its first visible light images of Venus.
• NASA's Cassini spacecraft flew by Venus twice during its mission to Saturn.
• NASA's Pioneer Venus Multiprobe, survived for about an hour after impacting the surface in 1978.
• NASA's Galileo spacecraft flew by Venus twice during its mission to Jupiter.
• Venus orbits the Sun at about 108 million kilometers.
• One day on Venus lasts 243 Earth days.
• Venus orbits the Sun faster than Earth, so one year on Venus takes only about 225 Earth days, making a Venusian day longer than its year.
• Venus has a solid surface covered in dome-like volcanoes, rifts, and mountains, with expansive volcanic plains and vast, ridged plateaus.