95

The answer is yes; for a few nights prior to the impact (assuming they had eyes with a similar sensitivity to our own and could look up!). It could be a bit longer than this if the body was larger than 10 km (it goes up roughly in proportion to the impactor's radius) and could be much longer if the object was a cometary body or had a very high albedo. ...


31

It could be as little notice as a few days. There is a large variation in the amount of warning we would have before an asteroid strike similar in energy to Chicxulub. Let’s examine the case in which we would have the least warning. The lower bound to the estimated energy released by the Chicxulub collision is 1.3e24 joules https://en.wikipedia.org/wiki/...


28

Ceres, Pallas, Juno and Vesta were all discovered between 1801 and 1807. After that, astronomers looked in vain for 38 years until the 5th, Astraea was spotted on December 8, 1845 by German amateur astronomer Karl L. Hencke by accident. He stumbled on Astraea while looking for Vesta one night. So, what took so long to discover Astrea? There is a paper1 which ...


25

The whole Earth "rippled" after the Chicxulub impact. By ripple, I specifically mean surface displacement. Current models indicate that it rippled enough that most of the dinosaurs and other species with brains certainly would have felt the ripple. How much did the Earth ripple? Well, that depends on the location. Meschede et al. [2011] in their ...


24

There were three attempts to measure Arrokoth by occultation, and the June 3rd attempt didn't detect anything. The July 10th attempt had a tiny blip, that appeared to be in the "wrong place", well away from the location that astrometry had predicted. The July 17th occultation was successful, it determined the shape and location well. Some thought ...


20

Yes and here's a video of "a Giant Comet Hitting the Sun": https://www.youtube.com/watch?v=Mat4dWpszoQ The impact occurred sometime during May 10-11, 2011. The comet was not named but believed to be a member of the Kreutz family of comets Many close calls Before this spectacular plunge we had witnessed several other comets graze (come close without ...


20

Of course you would need to specify who the person is - an Olympic athlete? Let us assume so and then you can scale downwards accordingly. So an Olympic high jumper can jump hard enough to raise their centre of gravity about 2m off the ground. Let us assume this is a ballistic problem. The athlete actually gives themselves sufficient upward speed to get ...


19

The recently discovered asteroids 2019 LF6 and 2020 AV2, each taking 151 days to orbit the Sun, have the shortest periods currently listed in the JPL Small Body Database. Vulcanoids are difficult to detect from Earth; none are known yet. To remain in such an orbit, Evans and Tabachnik 1999 estimate a minimum diameter of 100 m and a semimajor axis between 0....


18

This can be answered in two ways. At the Earth's orbit we do not necessarily sample (meteoroid intercepting Earth and surviving atmospheric entry to fall as a meteorite) all the taxonomic types (spectral classifications as presented by Bus et al., 2002, DeMeo et al., 2009, DeMeo et al., 2015) of asteroids in the form of meteorites. For example, more than ...


17

I'm pretty sure that the radial pattern found in the data is a result of WISE's approximately 90 minute sampling cadence (dictated by the satellite's orbit), astrometric precision (about 0.2 arcseconds in the stacked images around launch, see Wright et al. 2010), and the number of free parameters in fitting the asteroid orbits based on that data. See, in the ...


17

There are two classes of object. One is "asteroids" and the other is "comets". Asteroids orbit in fat ellipses, mostly between Mars and Jupiter, but some come closer and a few can come close to Earth. They are never very far from Earth and we discover new small ones all the time. These are "potentially hazardous objects". If ...


17

Your best viewing opportunity will be 99942 Apophis which will pass Earth on April 13, 2029, where it will pass about 19,600 miles from Earth; look out for that. According to Wikipedia: On that date, it will become as bright as magnitude 3.1 (visible to the naked eye from rural as well as darker suburban areas, visible with binoculars from most locations) ...


17

The JPL Small Body Database lists Apophis close approaches dating back 100 years before discovery. Three fairly close ones were: 1907-04-13, 0.029 au 1949-04-14, 0.028 au 1990-04-14, 0.033 au While it's possible to run a dynamical integrator arbitrarily far backward or forward in time, any given pos(t), vel(t) state is only a point in a cloud of ...


16

Well, that article was never accepted for publication in any peer-review journal apparently. That said, estimates may vary widely depending on assumptions about the composition and velocity of the asteorid. One could estimate the mass of the object assuming compositional ratios similar to a certain class of objects and integrating the whole Iridium deposits ...


15

We actually have a very good idea of this because the Mars Reconnaissance Orbiter has been orbiting Mars for over a decade. The MRO is, basically, a spy satellite around Mars and is continually taking high-resolution photos of the surface. It has revisted much of the surface, taking pictures multiple times over the years. As a consequence, we have a very ...


15

The Yarkovsky effect is the thrust on a small object in space that has been heated by sunlight, created from radiant energy. The YORP effect is when the thrust produces rotation, likely due to uneven heating or differences in surface projections (IE: A mountain acts as a better solar collector than a flatter portion of a spherical object on the opposite side)...


14

The strength of the Earth's gravitational field compared to the Moon and the Sun is not enough to capture and hold satellites - there are too many disruptive forces that would rip them away over time. However there are some objects at the Lagrangian points - the points where the gravitational fields of the Earth and other objects are equal and so it is ...


14

You are right that the tilt of the asteroids are distributed in very random way, and that the rotation of the Solar nebula is a minor contributor to that tilt, and only skews it a little. However, you are not right that randomness simply adds up. The randomness does in fact cancel out more and more when you combine a large amount of asteroids, until the ...


14

I also googled "iridium content of comets", and the first result was https://news.dartmouth.edu/news/2013/04/dartmouth-researchers-say-comet-killed-dinosaurs Now there is currently no consensus on the nature of the Chicxulub impactor. The observations of iridium and osmium suggest an asteroid. A minority opinion is that a comet may be responsible. The ...


14

There is a problem with very high velocity dust particles orbiting the Sun at distances much closer than Mercury with masses of micrograms and below. These particles can do damage to spacecraft that move close to the Sun in order to study it. With the Sun's standard gravitational parameter of 1.327E+20 m^3/s^2 and the vis-viva equation we see that at 0.1 AU ...


13

The objects you are refering to are actually two different objects: asteroids and comets. Meteor and meteorite are other names for an asteroid, at a given time of its interaction with our planet. We'll get to that. So first, what is the difference between an asteroid and a comet? A comet is a small solar system body that display a "coma" (an ...


13

By definition, gravity is a result of mass. Any body with a non-zero mass (even atoms) will have a gravitational field associated with it. The higher the mass the stronger will be the field. This is basic of classical mechanics. Until we reach quantum scale where the gravitational force is dominated by other 3 forces and the gravitational field becomes ...


13

It would be much better for Earth if the impactor hit the moon... In this Worldbuilding answer, I used a paper on ejecta kinematics to do calculations for ejecta velocity upon impact. Without going into too much detail here, much of the ejecta from a large impactor would not exceed the moon's escape velocity of 2.38 km/s. You can examine Figure 7 from the ...


13

The time of the orbit is not well known but the inclination can't change as much (small changes in velocity due to outgassing can significantly change the orbital period, but can't change the inclination much. So, while we have a good idea of it's orbital track close to perihelion, we just don't know when it will be there. We don't know where the Earth will ...


13

Some estimates which I found worth sharing: For fun, I searched for Chixculub TNT equivalent and e.g. ScienceDaily claims The energy released by the impact that blew out the Chicxulub crater was equivalent to about 100 million megatons, many orders of magnitude greater than the nuclear explosion at Hiroshima, a 15-kiloton blast. This seems to match up ...


13

If you visit https://ssd.jpl.nasa.gov/horizons.cgi and enter Apophis as the target body (full name "99942 Apophis (2004 MN4)"), you can go to the "Time Span" link and see "Available time span for currently selected target body: 1599-Dec-12 to 2500-Dec-30" It's possible others have calculated its position beyond this time span, ...


12

Many models shown in books or television show a very populated asteroid belt but in fact the belt is mostly empty. To answer your question, the inclination of the asteroids vary a lot going from 0° to 40° although most off them are in between 0° and 30°; See The orbital element distributions of real and modelled asteroids. So yes it would be 3 dimensional.


12

TL;DR version: Too big and way, way too late. The dispersal can't be done, even at the lower end of that 3-20 km scale. Holsapple claims 5 kilojoule/kg are needed to disrupt and disperse a solid 1 km asteroid asteroid, with energy scaling with radius1.65. Disrupting and dispersing a solid 3 km diameter asteroid with a density of 3 g/cc would require a ...


12

The computer program you are asking for is literally impossible: Even ignoring the affect of the greater universe and transient visitors such as comets on hyperbolic orbits, the Solar system is a chaotic complex system. We have a pretty good handle on the motion of the bodies we are, and have been aware of, during the time modern astronomy has been ...


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