# Tag Info

27

I'm a researcher at Curtin University working on the Desert Fireball Network. The DFN is the largest fireball observation network in the world, and our primary goal is to recover meteorites with orbital information attached. The traditional rule of thumb for meteorite-dropping events is a final luminous height below 35 km and a final luminous velocity below ...

19

yes it is possible,they are called Earth grazers or Earth-grazing fireball. they are not rare but only few incidents are recorded. for more details read this Wikipedia page https://en.wikipedia.org/wiki/Earth-grazing_fireball

18

Oxford English Dictionary is an authoritative source, but it's aimed at the general public. I think no astronomer will frown upon you when you're using the terms meteoroid and meteorite to describe a small body impacting another body in the solar system. As an example, Wikipedia doesn't impose the limitation that it must hit Earth: A meteorite is a solid ...

14

Wikipedia's entry for Heat Shield Rock says: Heat Shield Rock is a basketball-sized iron-nickel meteorite found on Mars by the Mars rover Opportunity in January 2005. The meteorite was formally named Meridiani Planum meteorite by the Meteoritical Society in October, 2005 (meteorites are always named after the place where they were found) The Meteorical ...

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

The process of differentiation is how metals like iron and nickel can become separated from less dense substances. It generally occurs in large, partly solid bodies in the early solar system, whose interiors are melted either via accretion energy, radioactivity or some combination of the two. A solid iron meteor is likely a fragment of a differentiated ...

10

The velocity of the impactor of tens of kilometers per second provides enough energy to heat the impactor and parts of the target to several thousands of Kelvins, so that parts are converted to plasma or to vapor, at least. According to Planck's law the color at these temperatures is white or bluish. According to the Stefan Boltzman law the total emitted ...

10

It’s been a while since I studied this, and meteorites are very much not my field, so I’ll share my current understanding but would welcome corrections from those more informed :-) These meteorites are mostly iron with a small amount of nickel. For a given composition of iron and nickel, there are different crystal structures that can be formed. Of ...

10

If this is something that you have found (rather than purchased as a meteorite) the chances are very small that it is a meteorite. Even if it is a meteorite, the chances it's a Martian one are even smaller still and none have been found in the United States. According to the Meteorites in the US page, which draws from the Meteoritical Society database, only ...

10

Well if no one is going to answer this I will. The answer is we don't know for sure. We speculate that there should be earth rocks on mars but until we 'see' one and analyze it we will not know for sure. The comments here all point to this answer. Mars hit with thousands of Earth rocks possibly containing life following asteroid impacte talks about the ...

6

Well there are some things to consider. Initially if you could make sure that after you blow up an asteroid you will end up with numerous but small enough pieces so that they will either: one, burn up in the atmosphere or two, be headed away from Earth (and not hitting us five years later) then we are OK, and blowing up the asteroid with a missile would be a ...

6

Asteroids are what are called minor planets - small inner solar system rocky bodies. Especially between Mars and Jupiter. Comets typically have highly elliptical orbits but they don't have to. The key defining feature of a comet is that it has a gaseous atmosphere and a tail when it passes close to the Sun. Comets are generally loose aggregations of ice, ...

6

The gravity of Earth did not change substantially. The strength of gravity on Earth is about 9.8, but varies between 9.76 and 9.83 ms-2(due to Earth not being a perfect sphere) This can be approximated from the mass of the Earth using $$g=GM_e/r_e^2$$ Where $M_e = 5.97219\times 10^{24}kg$ and $r_e= 6371000m$. The mass of the asteroid was about $10^{16}kg$...

6

You can use the Purdue 'Impact Earth!' website to estimate the effects of impacts of objects of various size, speed and composition. As detailed in the accompanying documentation, which was published in Meteoritics and Planetary Science, the energy calculation and atmospheric drag during entry is relatively straightforward physics; things like crater sizes, ...

6

Nice question, unfortunately your analoguous experiment is not as analoguous as you might hope. In your comparison image you are using both, not enough impactors, and a too tiny size distribution. Impactors on the Moon (or any other objects) follow a reasonably well-known size distribution where the smaller an impactor is, the more frequent collisions with ...

5

Mars is the only planet providing rocks with a similar chemical composition and age. So the origin of the meteorite is evident. This doesn't mean, that it's absolutely waterproof. There might have existed protoplanets similar to Mars 4 billion years ago, which since then have been swallowed by Jupiter, the Sun, or have been ejected out of the solar system. ...

5

There is a class of meteorites called Lunar Meteorites and several of those have been found on earth. Of course, it doesn't necessarily indicate whether we have actually witnessed a certain lunar meteor shower. Considering that nearly 100 metric tons of space debris falls on earth each day, one would imagine that it'll be colossally impractical to attempt ...

5

It looks to me that you probably have some misunderstanding of the term meteorite. A meteorite is a remnant body which has reached the surface of a major or minor body (a planet, a moon, an asteroid, etc.). The meteorite's parent body (a meteoroid) would definitely lose its entire water ice (if it had any at all) no later than during its passage through the ...

5

Finally, I managed to find such list (and even more): Meteoritical Bulletin. You can search for every location where at least one meteorite was found (including Mars and Moon). You can also choose among many other useful options. I found 15 on Mars and 2 on Moon, so I believe there are 17 extraterrestrial meteorites found.

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Moon Even though the Moon obviously isn't a planet, it's a good place to start as most of the observations of meteorites hitting other bodies has been focussed on the Moon. NASA runs the Meteoroid Environment Office which in part monitors lunar impacts. They state; The lunar impact rate is very uncertain because observations for objects in this mass range ...

5

It is certainly possible for rocks from Earth to be ejected and impact - and survive impact - on Mars. However, without doing specific isotopic analysis to determine the origin, one cannot simply look at a meteorite and determine its source body. No rovers that we have now have the capability to measure these isotopes. With that overview, it is much ...

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Scientists think they have - the Mojave crater. Also see https://science.sciencemag.org/content/343/6177/1343

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First, Terminology: Age is how old something is. Relative age is how old something is when compared to another (older vs younger). Absolute age is putting a number on that age (I am XX years old). Absolute model age is an absolute age that is based on a model, but where the age has not been measured directly (based on this cat's tooth, its absolute model ...

4

Yes, there is an observed impact of a comet into a celestial body. A fairly recent one in 1994 is the comet which impacted into Jupiter, Shoemaker-Levy-9 Here's a video of this event happening.

4

Meteorite abundances are referenced to their silicon abundance and then that is bootstrapped onto the hydrogen scale by assuming that the silicon abundance of meteorites is the same as that in the Sun. See for example Asplund et al. (2009). This means there is an additional uncertainty of a couple of hundredths of a dex when comparing meteoritic and solar ...

4

Your first resource here can be the impact effects calculator, It can show you when it is likely that a high velocity impact will occur. Somewhat surprisingly, faster objects are less likely to hit the ground at hyper-velocity, as they are more likely to break up and explode at altitude. They will likely form multiple meteorites, as the Chelyabinsk meteor ...

4

Since this has gone unanswered, I'm going to give it a shot. Probably the answer is no. We know that on some moons, volcanic eruptions do send material into space. Enceladus for example, feeds Saturn's E-ring. It regularly shoots about 200 KG per second into space. The other highly volcanic moon in our solar system is Io which shoots material high ...

3

Asteroids don't have control of their orbit. They are influenced by gravity; they obey the laws of physics. There aren't any traffic lights for them in space to obey so they know to slow down and stop to avoid a collision with a planet. They'll just carry right on going like someone driving through a red light. If it goes right in front of a planet at the ...

3

This page -- http://www.amsmeteors.org/fireballs/faqf/ -- suggests that it's very unlikely to find cometary-origin meteorites, even though the majority of observed meteors are cometary in origin, because the latter are too fragile to survive all the way to the ground: Based upon photographic fireball studies, cometary meteoroids have extremely low ...

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