Wednesday, August 21. 2019What are we made of?
From the biggest whale in the ocean to a tiny mouse, all life on Earth has one thing in common – it is all made from the same stuff. Stardust Nearly everything that makes up our bodies, and everything else on Earth, was created when dying stars exploded. These explosions send raw materials like carbon and oxygen hurtling across space, and these raw materials are what we are made of. That means that you are made of stardust! When the universe started, there was just hydrogen and a little helium and very little of anything else. Helium is not in our bodies. Hydrogen is, but that's not the bulk of our weight. Stars are like nuclear reactors. They take a fuel and convert it to something else. Hydrogen is formed into helium, and helium is built into carbon, nitrogen and oxygen, iron and sulfur—everything we're made of. When stars get to the end of their lives, they swell up and fall together again, throwing off their outer layers. If a star is heavy enough, it will explode in a supernova. So most of the material that we're made of comes out of dying stars, or stars that died in explosions. And those stellar explosions continue. We have stuff in us as old as the universe, and then some stuff that landed here maybe only a hundred years ago. And all of that mixes in our bodies.
Picture Credit : Google Wednesday, August 21. 2019How is the life on earth?
Although there may be life elsewhere in our Solar System, we haven’t discovered it yet. The only place we know has life for sure is Earth. Our home planet is at just the right distance from our Sun for liquid water to exist, and has all the other key ingredients to make life possible. Life is a characteristic that distinguishes physical entities that have biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased (they have died), or because they never had such functions and are classified as inanimate. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. The criteria can at times be ambiguous and may or may not define viruses, viroids, or potential synthetic life as "living". Biology is the science concerned with the study of life. There is currently no consensus regarding the definition of life. One popular definition is that organisms are open systems that maintain homeostasis, are composed of cells, have a life cycle, undergo metabolism, can grow, adapt to their environment, respond to stimuli, reproduce and evolve. However, several other definitions have been proposed, and there are some borderline cases of life, such as viruses or viroids. Recipe for life In the mixing bowl are the key ingredients needed for life as we know it: You will need: Raw materials, such as oxygen, nitrogen, and carbon Raw material The raw materials needed for life are found all over Earth – for example in soil. However soil needs water and energy from the Sun before life can appear. Life as we know it contains specific combinations of elements including carbon, hydrogen, nitrogen, and oxygen that combine to form proteins and nucleic acids which can replicate genetic code. All the basic elements are formed in stars and distributed throughout space as a result of giant explosions called supernovas. Since these essential chemicals are quite common in other places in the Universe we can expect that the development of life somewhere else is also possible. Water Liquid water is essential for life. It allows crucial changes to take place between raw materials. Liquid water is essential because biochemical reactions take place in water. Water is also an excellent solvent that easily dissolves and carries nutrients and other compounds in and out of cells. Life forms are usually made primarily of water. In fact, our human bodies are more than 60% water. Energy Life on Earth would not be possible without a constant source of energy, such as the Sun. Organisms require energy to assimilate or put together the chemicals that form an individual. Energy is also required for the organism to grow, reproduce, and respond to the environment. Energy sources may include other organisms, light, or inorganic compounds. The most common source of energy on the Earth is photosynthesis, which transforms sunlight into food. This process will not work very well for the outer Solar System, because not much light reaches such great distances. However, we can look to extremophiles here on Earth for help in figuring out where and what to search for. Extremophiles live in extreme conditions and typically get their energy from a source other than the sun.
Picture Credit: Google Wednesday, August 21. 2019Who is Earth’s Evil twin?
Earth and Venus are about the same size, and are made up of similar rocky materials. They are also neighboring planets. However, Venus and Earth are also very different. Venus has an atmosphere that is about 100 times thicker than Earth's and has surface temperatures that are extremely hot. Venus does not have life or a water ocean like Earth does. Venus also rotates backwards compared to Earth and the other planets. But that’s where the similarities end! Venus is a deadly world. It‘s boiling hot, covered in volcanoes, and cloaked in an atmosphere of deadly poisonous gases Volcanoes: Venus is covered in volcanoes. There is evidence that some may still be erupting. On Earth, volcanoes are mainly of two types: shield volcanoes and composite or stratovolcanoes. The shield volcanoes, for example those in Hawaii, eject magma from the depths of the Earth in zones called hot spots. The lava from these volcanoes is relatively fluid and permits the escape of gases. Composite volcanoes, such as Mount Saint Helens and Mount Pinatubo, are associated with tectonic plates. In this type of volcano, the oceanic crust of one plate is sliding underneath the other in a subduction zone, together with an inflow of seawater, producing gummier lava that restricts the exit of the gases, and for that reason, composite volcanoes tend to erupt more violently. Barren surface: There are no rivers or lakes on the surface of Venus. The only rain it gets is acid rain that would burn trough your skin. Toxic clouds: Venus is covered in clouds of sulphuric acid. The atmosphere is so thick it would crush you in seconds. Temperature: The surface temperature on the planet Earth goes only to about 100 degrees Fahrenheit, which makes it possible for life to thrive on this planet. On the other hand, the surface temperature on the planet Venus is nine times hotter than that on planet Earth. As such, it is extremely impossible for any form of life to survive and thrive on Venus’ surface.
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