While the chances of a deadly asteroid hitting Earth are low, the damage that one could produce could result in a cataclysmic event. While it may seem that stopping an asteroid en route to Earth is impossible, there are actually certain technologies that could possibility lessen the damage. The most important thing to do is accurately track asteroids that could collide with Earth. In terms of actually deflecting an asteroid, the best option is to send a robotic probe on a collision course with the goal of knocking it off course. Scientists believe this would be effective with asteroids up to 1,300 feet.
While cataclysmic asteroid events are rare, smaller ones are much more frequent and can still cause immense damage. Thus tracking asteroids remains an important issue for those studying space.
The transit method has already been used to discover a few thousand exoplanets and continues to discover more through both old observations and current missions. With this method, the brightness levels of stars in other solar systems are measured. When the brightness dims, this is a sign that an extrasolar planet may have passed in front of the star. It is possible for the change in brightness to be due to natural changes in the star so the exoplanet is confirmed through both continued monitoring of the star (to see if the planet passes through again along its orbit) and another method of detection such as the Doppler method.1 Despite the fact that the transit method can only discover planets with orbits that are edge-on to Earth, it is the exoplanet detection method that has found the greatest number of extrasolar planets.
This method can be used to discover useful data about the planets, including the size of the planet, the size of the planet’s orbit, and the composition of the planet’s atmosphere. The planet’s period can be determined by how long it takes to return to the near-side of the star and its size can be determined by how much the star’s brightness dims when the planet passed in front of it. When light from the star travels through the planet’s atmosphere, we can determine its atmospheric elements. These factors, along with the temperature of the star itself, are crucial to our analysis regarding the habitability of the planet.
Three major missions have been and continue to be crucial to our discovery of extrasolar planets. The Kepler Mission led to the discovery of over 2500 extrasolar planets1 and its data could lead to thousands more. The TESS mission is about a day away from its third birthday as of the time of this blog post and has observed 75% of the sky. It has confirmed 66 new exoplanets and has found about 2100 candidates to possibly be confirmed by scientists on Earth. Finally, the European Space Agency has produced the CHEOPS mission with a 19 arcmin by 19 arcmin view of the sky.
Hopefully one of these exoplanets either currently holds life or has the potential to hold life as our “Planet B.”
[1] Bennett, Jeffery, et al. The Cosmic Perspective: The Solar System. 9th ed., Pearson, 2020.
With earth being the only known habitable planet in our solar system and little knowledge regarding what lies outside of our solar system, its easy to feel like we are the only ones in the universe. However, would you still think that if you knew that NASA has confirmed 4,375 planets outside of our solar system? Along with that, they have discovered 3,274 planetary systems. The first exoplanet was discovered only 26 years ago so it is likely that they will discover many many more exoplanets! Through the use of a space telescope, NASA has gathered enough information to estimate that there are actually more planets than stars in our solar system. Many of the planets that have been discovered are also similar in size to Earth. While the idea of aliens may seem crazy, the thought of discounting any possibility of life among the thousands (that we know of, and probably many many more) of planets that exist outside our solar system (that we know essentially nothing about) is even crazier to me!
Titan is one of 62 moons revolving around Saturn. Before 2004, not much was known about Titan, other than the fact that it is Saturn’s largest moon. NASA sent the Cassini spacecraft to the outer to investigate and send back information about Titan. Cassini sent back pictures of a very planet-like moon with a dense atmosphere. This makes Titan the only moon in our solar system with a rich atmosphere.
Titan also has its own water cycle, meaning liquid hydrocarbons are rained from the atmosphere. As it is too cold for liquid water, liquid nitrogen, methane and ethane create most of the hazy atmosphere, and gather on Titan’s surface to create the icy mountains and massive seas that are seen by Cassini. Under the surface, however, scientists believe that Titan has an active core creates a layer of liquid water and ammonia.
Despite the vast distance from the Sun, Titan is one of the most habitable places for life in our Solar System.
Ceres is a dwarf planet discovered by Giuseppe Piazzi in 1801. Its mass is only .015 percent of Earth’s and it is actually small enough to be classified as both a dwarf planet and an asteroid. Moreover it is sometimes referred to as the largest asteroid in the solar system.
Ceres is round, though it has a bugle at its equator due do its rotation and recent probing has led many scientists to believe that there may be a possibility of water on its surface and ice volcanoes.
While there is still much that is unknown about Ceres, its low mass and closer proximity to Earth have led scientists to believe that it could one day act as a launching point for deep space missions in the future.
Unlike recently discovered dwarf planets, Ceres was discovered in 1801. Ceres was the first asteroid discovered, it was first spotted on Jan. 1, 1801 by Sicilian astronomer Giuseppe Piazzi. Ceres was named after the Roman goddess of agriculture. An interesting fact about Ceres was that after it was discovered an element in the period table was named after it(cerium). Cerium is the most abundant of rare-earth materials. In the last decade there were 2 bright-spots found on Ceres, Due to Ceres’s massive size for a dwarf planet(590 miles) its actually far more spherical than other dwarf planets. A very cool fact about Ceres is its potential to have an atmosphere, even though Ceres is very far away from the sun its temperature comes to around -37 Fahrenheit . Thus the ice water could sublimate into a gas causing an atmosphere to form.
It is only right to dedicate a blog post to the very things that inspired my username: comets! Comets are small objects that orbit the Sun and tend to have more eccentric orbits than other bodies in the solar system. A comet consists of a nucleus, coma, ion tail, and dust tail. The nucleus is solid and mostly composed of volatile ices, silicate, and organic dust particles. The coma is the bright and flowing atmosphere surrounding the nucleus that is caused when the comet gets near the Sun and its ices sublimate. The ion tail is typically blue due to the CO+ ions in it. It is created when solar wind sweeps away ionized volatile gases found in the coma; the volatile gases are ionized by ultraviolet photons coming from the Sun. The dust tail is made up of dust particles that are pushed backwards by solar radiation pressure, producing a tail that tends to be long, curved, and either yellow or white.
Additionally, comets are usually named after the people who discovered them. Sometimes, they are named after the individuals who first noticed that they had periodic orbits. A “C” before a comet’s name indicates that it has a long period while a “P” before a comet’s name indicates that it is periodic. A “D” before a comet’s name means that it is deceased or destroyed. These are just a few examples of the great detail that goes into naming a comet.
Photo of Comet West in 1976 (taken from Britannica)
With the rate at which we are destroying our planet, we are likely to need a new Earth sometime in the future. Luckily for us, there are two potentially habitable planets that were discovered in the Kepler 62 System, called Kepler 62e and Kepler 62f. These planets are 60 and 40 percent larger than Earth respectively, but both are in the habitable zone of the planetary system. In this “Goldilock’s zone”, temperatures are moderate enough to support liquid water, and thus could sustain life as we know it. These planets orbit a star slightly smaller than our Sun, at the equivalent distance of Mercury and Venus in our Solar System. The only problem is that this system is 1,200 light years away. Not only does it make traveling to these planets impossible, this distance makes it extremely difficult to measure the compositions of the planets. However, Lisa Kaltenegger of Harvard-Smithsonian Center for Astrophysics and the Max Planck Institute for Astronomy modeled the conditions of these planets, and found the worlds to be humid, cloudy, and have liquid oceans. Life on these planets could potentially be aquatic, although these are educated guesses and may only be confirmed by our descendants.
The telescope that discovered these planets was the Kepler space telescope. During Kepler’s almost decade long stint in space, over 2500 planets were discovered with 678 GB of data collected. Kepler 62e and 62f represent only two of these planets and a fraction of the data collected. It will be interesting to see how our discovery of exoplanets increases as technology improves.
Life as we know it needs three major ingredients, at least according to NASA. Life needs water, the correct chemical makeup, and an energy source. Europa, one of Jupiter’s moons, could have all three ingredients and is a candidate for sustaining life elsewhere in the Solar System. In terms of water, Europa has oceans that may be greater in volume than Earth’s oceans. Evidence for water on Europa comes from Galileo’s flyby missions, which detected a magnetic field that could have been generated by an ocean of salty water. Europa also experiences tidal flexing, which can generate enough heat to form an ocean. In terms of chemistry, life as we know it needs the following elements: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. These are common elements, which may have been already on Europa since its initial formation and can arrive in the form of impacts. Lastly, in terms of energy, Europa is too far from the Sun to have life based on photosynthesis. Instead, possible life on Europa needs to rely chemical reactions. Europa gets radiation from Jupiter, which splits the oxygen and hydrogen molecules in water. Oxygen is reactive, and if it falls into the global ocean, it can be used as a chemical energy source. Thus, according to the astrobiologists at NASA, the possibility of life on Europa is realistic.
This is not to mention that these three major requirements are only for life as WE know it. It is entirely possible that in the future, we come across something that does not meet our expectations for life and requires an entirely different habitat. I personally think that because of the sheer scale of the universe and different permutations for life, it is unrealistic to believe that all life forms are carbon based. Non-carbon-based life may not need any of the three major requirements listed above.
The Kepler mission marked a significant jump in exoplanet discovery when the space telescope was launched over 10 years ago. Since then, astronomers worked hard to research, develop, and design a more modern approach to discovering these distant and unknown planets. The solution was the Transiting Exoplanet Survey Satellite (TESS). TESS’s mission was to look at the stars close to Earth that shined the brightest to find the exoplanets that orbit them. When compared to the Kepler telescope, TESS is able to perform the transit method on a significantly larger area of space than Kepler. In sum, TESS’s advanced technology including multiple modern wide-angle cameras enabled 400 times greater area of surveillance for transiting.
The surveillance covers around Earth’s entire surface facing outward, resulting in 26 different sectors of space to cover. In the two year cycle, each hemisphere of the globe is covered in one year beginning in the southern hemisphere and then moving to the northern hemisphere. TESS completed the southern hemisphere in 2019, and began the second year of the process. In fact, TESS was so successful that the mission was extended in the summer of 2020 once it completed the northern hemisphere’s mapping. The extension adds new targets for TESS to focus on filling in small gaps the first two-year cycle missed, and includes new coverage of areas around the ecliptic. After three years in the sky, TESS has amassed a collection of 2200 exoplanets discovered and will continue to add to its collection over the next year and a half. The gif below shows TESS’ orbital patterns over its lifetime.
Animation of TESS from April 18, 2018 to December 18, 2019 (via Wikipedia)
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