Top 10 Most Astonishing Asteroids w/ Scott Manley

there are literally millions of asteroids in our solar system and surprisingly there are also many different types they're not just found in the asteroid belt but they are in reality darting all around our solar system my name is Scott Manley and you're watching astral and today we're going to discuss some of the most interesting asteroids we've discovered so far but what exactly is an asteroid and what's the difference between an asteroid and a comet well an asteroid is a minor planet or a small solar system body a minor planet is an astronomical term for a small solar system body which is not outgassing they're generally rocky or metallic but may contain volatile compounds underneath the surface protected from sunlight comets on the other hand have these volatile materials near the surface and when they are heated by the solar radiation they produce coma and tails this distinction between asteroids and comets has existed for over a century however the lines are a lot more blurred than we've first thought the level of activity from a body is largely dependent upon its distance from the Sun objects which exist far beyond the orbits of Neptune are inert all year around but if they were to be brought in close to the Sun they would turn into comets so just keep that in mind while watching in this video we will only talk of asteroids which have orbits in the inner solar system or in other words between the Sun and Jupiter not all asteroids are the same there's obviously a difference in size from dust particles all the way up to the biggest known asteroid which is almost 1,000 kilometres in diameter asteroids are also classified based upon their spectrum or color which often indicates what the asteroid is made of there are three main spectral categories that most asteroids fall into there are the C group which are dark carbonaceous asteroids the S type which are stony or sill Acacia asteroids and the M types which are metallic asteroids there are other types too but these are the three main categories we might mention some of these as the video progresses but they are basically variations on these three groups that I just mentioned know let's count down the top 10 most interesting asteroids 2005 VX 3 is the main our planet with the largest aphelion that we know off at its closest approach to the Sun is only 4.1 au OE which is inside the orbit of Jupiter but when it's farthest away it has a massive estimated heliocentric distance of a 3,000 au from the Sun because of this it is estimated to have the largest orbital eccentricity of any non-main or planet the last time it was seen was January 2006 when it came to perihelion and it probably won't be seen again for another 30 to 40 thousand years it could well be a dormant comet that has not seen outgassing it may have made closer approaches to the Sun in the past which would have removed most of the volatile icy materials hence why it has no tail and why we don't recognize it as a comet it is estimated to be about seven kilometers in diameter number 9 9 9 9 42 Apophis is a near-earth asteroid which caused a bit of a stir in December 2004 because the initial observations indicated a probability of about 2.7 percent that it would hit the earth on April 13th 2029 not to worry however as additional observations improved this asteroid predicted orbit which eliminated their chance of collision in 2029 however the possibility remains that during this very close encounter with earth a Pops's could pass through what's called a gravitational keyhole a small region of no more than about 800 meters wide that would alter its orbit sufficiently to put it on a future impact scenario exactly seven years later in 2036 this possibility kept it at level 1 in the Torino impact scale until August 2006 when the probability that Apophis would pass through this keyhole was determined to be very small now at this point in time the possibility has effectively been ruled out Apophis did however set the record for highest rating on the Torino scale reaching a level four at one point had it hit earth the estimated kinetic energy would have been about seven hundred and fifty megatons thirteen times more powerful than the largest hydrogen bomb ever exploded Apophis is a stony s-type asteroid the most recent observation of it in 2013 estimated the asteroid to be about 325 metres across interestingly an asteroid the size of Apophis is expected to hit earth about every 80,000 years on average let's hope the next one isn't too soon number 825 143 Ichikawa this is a Mars crossing asteroid in other words it crosses inside the orbit of Mars it was a first asteroid to be the target of a sample return mission accomplished by this Japanese space probe Hayabusa and this is the smallest asteroid ever to be photographed by a spacecraft being only 500 meters across at its longest point it is an S type asteroid but it may be a contact binary that means it would effectively be two separate asteroids which have merged over time it has very little in the way of impact craters and is covered in boulders described by the mission team as a giant rubble pile the estimate its average density to be about one point eight grams per cubic centimeter which means it can't possibly be solid rock but more like fragments of gravel that have built up over time interestingly its gravity wasn't strong enough to enable the space probe to go into orbit around it instead they parked the space probe next to the asteroid and orbited the Sun alongside it in 2010 we landed on the asteroid and successfully returned dust samples from its surface to earth number seven Palace Palace is a second asteroid to have been discovered after series when astronomers were looking for Ceres again after its initial discovery in the early 1800s they accidentally found palace instead which coincidentally was near series at the time when Palace was discovered it was counted as a planet as were other asteroids in the early 19th century the discovery of many more asteroids after 1845 led to the reclassification as minor planets palace is one of the largest asteroids in the solar system it is estimated that it comprises seven percent of the mass of the asteroid belt and as diameter of 544 kilometers is slightly larger than that of Vesta but it is about 10 to 30 percent less massive than Vesta placing it third amongst the noon asteroids in terms of mass palace is a SI group asteroid which means it has a very low albedo giving it a dark surface that reflects only 4% of the light falling on it that's equivalent of fresh asphalt at its brightest it may be visible with binoculars but not with the naked eye the Palladian orbit is inclined at 34.8 degrees to the plane of the solar system meaning that it's practically inaccessible to any spacecraft which might want to run give you an investigated slope more closely number-6 101 99 charcoal now this asteroid technically shouldn't be on this list but we had to include it due to its remarkable ring system the reason it shouldn't be on this list is because it's what we call a centaur a main our planet that orbits within the orbits of outer planets in this case uranus and saturn it is the largest known centaur being over 300 kilometers in diameter and like I mentioned it has a ring system much like on Saturn but just on a much smaller scale in 2013 it was discovered that it has two rings one seven and the other three kilometers wide both being about nine kilometers apart it is a smallest known object to ever have rings in fact because it's so small these rings shouldn't be stable at all either they are actively contained by shepherd moons or they will slowly wane and disperse over the next few million years number five Leticia Leticia is a large M type asteroid it has a retrograde rotation is found in the asteroid belt it measures about 100 kilometers in diameter and has one of the greatest densities of any asteroid observed it's average density is estimated to be about 3.4 grams per cubic centimeter meaning that it must be made of metal rich rock but rather bizarrely there is little evidence of metal on the surface and its color resembles more a C group carbonaceous asteroid due to the density though we know that it must indeed have metals contained within it and it is speculated that the metal rich core of the asteroid is surrounded by a three kilometer thick layer of dust and rubble we call regolith this theory is backed up by the way that impact craters on the surface have softened outlines latisha has an irregular shape and is heavily cratered with the largest impact crater reaching 45 kilometers in diameter number 4 433 eros is an S type asteroid approximately 34 kilometers long and it is a second largest near-earth asteroid after 1036 Ganymede eros is a Mars crossing asteroid and it was the first asteroid known to do so objects of this kind orbit can remain there only for a few hundred million years before the orbit is perturbed by the gravity of Mars eros may evolve into an earth crosser with the short interval as two million years and apparently has roughly 50% chance of doing so in the time scale of about a hundred years which means it will eventually become a potential Earth impactor comparable in size to the impact to the creator the Chicxulub crater that led to the extinction of the dinosaurs the equivalent of a hundred tera ton weapon the near shoemaker probe visited eros in 1998 and 2000 finishing its mission by actually landing there in the surface it was not designed to be a lander and if that doesn't get you interested in Eris the data collected suggested that it contains about 20 billion tons of rare metals such as gold and platinum number three 243 Ida it is a stony s-type asteroid found in the asteroid belt in 1993 Ida was visited by the spacecraft Galileo as it was bound for Jupiter Ida has an average diameter of 31.4 kilometers and it is irregularly shaped and elongated apparently composed of two large objects connected together its surface is one of the most heavily cratered in the solar system its density is about on average for an asteroid at a bit 2.6 grams per cubic centimeter unlike all asteroids it has very weak gravity theoretically you could jump from one end of the asteroid to the other in one go if you exceeded 20 m/s you can actually escape the asteroids gravity altogether but what is most fascinating about Ida is it's moon dactyl being only 1.4 kilometers in diameter is about one twentieth of the size of Ida it was named after the dactyls creatures which inhabited Mount Ida in Greek mythology dactyl and Ida's share many characteristics which imply they came from the same place we know of other asteroids which have moons but Ida is the only one that we have high-definition imagery off number 2 vesta Vesta is the second most massive object in the asteroid belt after the dwarf planet Ceres with a mean diameter of 525 kilometres Vesta is the last remaining rocky proto planet which means that has differentiated interior similar to the ones formed by the terrestrial planets numerous fragments of Vesta rejected by collisions billions of years ago these left two enormous craters occupying much of Vesta southern hemisphere debris from the impact has since fallen to earth as hammered it-- you create Diogenes meteors which have a valuable source of information about Vesta other fragments stayed in a similar orbit to Vesta and there are so many of them that along with Vesta they have been given their own class of asteroid the V type Vesta is the brightest asteroid visible from Earth it also has the tallest mountain in the solar system call rheasilvia NASA's Dawn spacecraft entered orbit around Vesta in 2011 for one year exploration there is now a huge amount of data on this asteroid and researchers are still sifting through this data three years after dawn left number one Ceres and finally the only dwarf planet in the asteroid belt Ceres for many years was considered a planet due to his size which is about 960 kilometers in diameter composed of rock and ice Ceres is estimated to make up about 1/3 of the mass of the entire asteroid belt it is so big it is the only asteroid rounded by its own gravity but even though it was the biggest asteroid in planetary terms it is still rather small our moon in comparison is huge it is believed that Ceres has a rocky core and icy crust and may have a remnant internal ocean of liquid water under a layer of ice it is carbonaceous c-type asteroid meaning the surface is probably a mixture of water ice and carbonates in clay emissions of water vapour have been detected from Ceres this was unexpected as asteroids in the asteroid belt do not usually give off vapour as that's more like a comet the NASA spacecraft Dawn entered orbit around Ceres in 2015 after finishing its mission around Vesta two distinct bright spots inside a crater appeared on the surface in imagery sent back by Dawn the spots are likely to be highly reflective materials containing ice or salts NASA then released a higher resolution image showing that instead of one or two spots there are actually several well thanks for watching this far I hope you've learned something today about asteroids and they've fueled your interest to go out and find more about them I've only mentioned ten today but there are so many more to discover for yourself we can delve deeper into vast dense use as we've only just scratched the surface of them in this video so if you want more videos about space be sure to subscribe to astral and also check out my channel where I do my best to combine science and video games at the same time I'm Scott Manley fly safe

Channel: Astrum

Views: 207,468

Rating: 4.9039998 out of 5

Keywords: Asteroid (Celestial Object Category), Astronomy (Field Of Study), Scott Manley, astrum, astrumspace, 4 Vesta (Asteroid), Ceres (Asteroid), ida, eros, lutetia, 99942 Apophis (Asteroid), 2005 vx3, pallas, chariklo, Comet (Celestial Object Category), Rosetta (Spacecraft), dawn, NEAR Shoemaker (Spacecraft), NASA (Spacecraft Manufacturer), itokawa, European Space Agency (Space Agency), JAXA (Space Agency), Hayabusa (Space Mission)

Id: mQHfGP5kpr8

Length: 15min 16sec (916 seconds)

Published: Thu Jul 02 2015