Meteorite Impacts and Frequency

Podcast

Play an AI-generated podcast conversation about this lesson

Download our mobile app to listen on the go

Get App

Questions and Answers

Match the term to its description related to objects entering Earth's atmosphere:

Meteoroid = A small particle from dust to a few meters across in space. Meteor = A meteoroid that enters Earth's atmosphere. Meteorite = A meteoroid that survives passage through the atmosphere and hits Earth's surface. Airburst = Explosion of a meteoroid in the atmosphere.

Match the size of the impactor with its typical effect:

< 10 m = Burns up in the atmosphere or hits the ground with no effect. 10-100 m = Disintegrates in the atmosphere (airburst). 100 m - 1 km = Capable of hitting the surface and forming a crater with localized effects.

1 km = May cause severe global effects.

Match the term with the appropriate description:

Asteroid = A rocky or metallic body, often found in the asteroid belt. Comet = An icy body with a glowing tail of gas and dust. Oort Cloud = A spherical region far from the Sun where many comets originate. Kuiper Belt = A region beyond Neptune containing icy bodies, including comets.

Match the name of the crater to where it is located:

Vredefort Crater = South Africa Chicxulub Crater = Yucatán Peninsula, Mexico Sudbury Basin = Northern Ontario, Canada Popigai Crater = Siberia, Russia Signup and view all the answers

Match the estimated sizes for each impactor:

House size = Could explode in atmosphere with more force than Hiroshima blast and flatten everything within 2.5 km Football field size = Would flatten New York City and cause moderate earthquake felt over 1600 km away Mt. Everest size = Would vapourise everything for many km and make a crate over 160 km across. Most life would die. London UK size = Would change Earth's orbit Signup and view all the answers

Associate the impact size with how often it occurs on Earth:

Atmospheric explosion / small crater = Every hour / Every day Tsunamis, widespread devastation, climate change = Every century / Every millennium Mass extinction = Every million years / Every hundred million years No major impacts = Once in Earth's history Signup and view all the answers

Match the following terms related to comets:

Icy Core = Frozen water, carbon dioxide, carbon monoxide and small amounts of other chemicals Oort Cloud = Where astronomers believe comets form (outside the solar system) Asteroid Belt = Where some comets can be found within the inner solar system Kuiper Belt = Where some comets can be found on the outer part of the solar system Signup and view all the answers

Match the crater with its primary distinction

Vredefort Crater = One of the oldest and largest confirmed impact structures on Earth Chicxulub Crater = Associated with the Cretaceous-Paleogene extinction event Sudbury Basin = One of the most studied and economically important impact craters Popigai Crater = Known for the presence of impact diamonds Signup and view all the answers

Match the term with the hazard that it causes:

Tsunamis = Most land in oceans, would create tsunami Wildfires = Superheated gas and debris reach temperatures capable of drying and igniting living vegetation Earthquakes = Seismic waves created from impact can be severe Volcanic Eruptions = Impacts cause melting and instability in Earth's mantle Signup and view all the answers

Match the crater size to its classification:

Microcraters = < 10 mm diameter Small craters = 10 mm – 15 km diameter Large craters = 15 – 300 km diameter No classification given = > 300 km diameter Signup and view all the answers

Match each value on the Torino Scale with its description:

0 = Likelihood zero or near zero 1 = Routine discovery; near miss 5 = Close encounter- serious, but uncertain threat; possible regional devastation. 10 = Collision certain; global climate catastrophe; civilization threat Signup and view all the answers

Categorize the efforts done to minimize hazards due to meteor impacts:

Spacewatch = An inventory of objects with diameters > 100 m in Earth-crossing orbits. NEAT Project = Identify objects of diameter of 1 km Nudging objects = Gentle (ion thruster for 50 years) or not gentle (nuclear blast) to push the objects out of path. Evacuation Measures = Depending on the impact point, move people away from danger Signup and view all the answers

Match the terms for the threat level that comets and asteroids pose to Earth:

Comets = Our first warning is likely to be their initial entry into Earth's atmosphere (hard to predict) Asteroids = Orbits continuously modified by gravitational perturbation of the asteroid belt NEO's Trajectories = Orbital trajectories of only 200 are known, but the paths of 90% of the asteroids that threaten Earth are unknown Largest NEO's = The diameters of about 35% of asteroids >5 km diameter are known Signup and view all the answers

Match the event below to how big of a crater it creates:

Tunguska Event = Asteroid 50-100m in diameter created airburst in Siberia June 1908 Vredefort Crater = 1 impactor with at least a 10 km diameter, created world heritage site Sudbury Impact = 10-15 km diameter created what would become one of the most studied sites on Earth Chicxulub Crater = 10-150 km diameter which would cause significant Tsunamis Signup and view all the answers

Match the term to its description in the context of meteorite impacts

Panspermia = The theory that meteorites can carry elements that can produce life or microscopic organisms. Torino Scale = A scale to communicate the potential risk of impact events to the public. Oort Cloud = A spherical region far from the Sun where many comets originate. NEO = Near-Earth Objects (Asteroids whose orbits cross that of Earth.) Signup and view all the answers

Match the crater to one thing it's known for:

Vredefort Crater = 380km estimated diameter. Chicxulub Crater = Likely caused Mega-Tsunami Reaching US Gulf States Sudbury Basin = Important Nickel Mining Site Popigai Crater = Shock from impact created Diamonds Signup and view all the answers

Match each word related to comets:

Comets = Particles that are grouped by size and composition Range = A few metres to several hundred km in diameter Consist of = A rocky core surrounded by ice and covered in carbon-rich dust Where it lives = The Oort cloud Signup and view all the answers

Match the object with what it is made of:

Asteroid = Composed of rock, metal or a combination Comets = Consist of a rocky core surrounded by ice and covered in carbon-rich dust Meteoroid = Probably made from broken Asteroids Meteorite = Meteoroid that hits Earth's surface Signup and view all the answers

Match the location with what it is:

Comets Live = Astronomers believe they formed outside the solar system and were then thrown into an area called the Oort Cloud Asteroid Belt = Also where comets can reside in the inner solar system Kuiper Belt = Comets also occur here in the outer solar system Hard to Predict = Our first warning is likely to be their initial entry into Earth’s atmosphere Signup and view all the answers

Match how the impact can alter climate change

Climate Change = Often involves rapid climate change, triggered by… Mass Extinctions = Sudden large loss of life Volcanic Activity = Alters amount of tectonic plates Extraterrestrial Impact / Airburst = Injects large amounts of dust into the atmosphere, that causes cooling Signup and view all the answers

Match what is created through meteorite craters:

Involve... = High velocity, energy, pressure and temperature Rocks... = Become metamorphosed or melt with other materials Kinetic energy... = Impact produces seismic shock wave. Seismic Shockwave = Can cause tsunamis Signup and view all the answers

Match the following terms about the Torino Scale

Normal = Routine Discovery; near miss Meriting Attention = Close encounter; merits astronomer attention Threatening = Close encounter - serious but uncertain threat; possible regional catastrophe Certain Collision = Collision certain; unprecedented regional destruction, major tsunami Signup and view all the answers

Match the sizes to the following potential impactors

Car Size = Burns up in the atmosphere House Size = Could explode in the atmosphere with more force than 1945 Hiroshima nuclear blast… Football Field Size = Would flatten New York City and cause M 7.7 earthquake felt over 1,600km away. Mt. Everest Size = Would vapourise everything around for many km and make a crater >160 km across; most life would die as dinosaurs did 65 million years ago Signup and view all the answers

Match the term to its definition:

Asteroids = Are found in a belt between Mars and Jupiter Meteoroids = Are particles from dust to a few metres across Meteor = A meteoroid that enters Earth’s atmosphere Meteorite = Is a meteoroid that hits Earth’s surface Signup and view all the answers

Match how the size of meteorites affects the Earth

<10m Diameter = Burns up in the atmosphere, or if very small, continues to hit ground with no effect 10-100 m Diameter = Disintegrates in the atmosphere (airburst) 100m - 1km Diameter = Capable of hitting surface and forming crater with localized effect <blockquote> 1 Diameter = May cause severe global impact </blockquote> Signup and view all the answers

Match which event may have led to one or more others.

Wildfires = Comes as a result of the superheated gas and debris reach temperatures capable of drying and igniting living vegetation. Mass Extinction = Injects large amounts of dust into the atmosphere that causes cooling. Volcanic Eruption = Impacts cause melting and instability in Earth’s Mantle. Earthquakes = Seismic waves created from impact can be severe. Signup and view all the answers

Match The Torino Scale number to its number label

0 = No hazard 1 = Normal 2 = Meriting attention by astronomers…. 6 = Threatening Signup and view all the answers

Match which city the following site will be found in

Vredefort = Free State, South Africa. Chicxulub = Yucatán Peninsula, Mexico. Sudbury Basin = Northern Ontario. Popigai = Siberia, Russia. Signup and view all the answers

Match the name of asteroid/object to its description

Asteroid = A rocky or metallic body, often found in the asteroid belt. Comet = An icy body with glowing tails of gas and dust. Oort Cloud = A spherical region far from the sun where many comets originate. Kuiper Belt = A region beyond Neptune containing icy bodies, including comets. Signup and view all the answers

Match how the size and frequency of impacts affect the Earth.

Impact size < 1 km = Causes atmospheric explosions / or small craters every day!! Impact size 1 km = Tsunami widespread, devastation, climate change. Impact over 10 km = Creates a mass extinction. Impactor Unknown size = Once in Earth's history!! Signup and view all the answers

Match potential steps that can be taken or be on the lookout towards seeing if an object is coming towards Earth

Spacewatch = Inventory objects with diameters greater than 100m in Earth crossing orbits! NEAT Project = Identifies objects diameter that is 1 km! Characterize mechanical properties = Are they solid or rubble piles. Nudge Object = Potential use nuclear blast, if the other two aren’t a potential. Signup and view all the answers

Match which crater of the world caused the following event

Asteroid = Estimated that 10-15 km impact hit 1.8 B years old. Impact = Debris scattered over 1,600,000 km2. Designated by = The United Nations as a geopark Nickel = Important mineral mining site. Signup and view all the answers

Match the crater known about it!

First = Mass Extinction, which could include dinosaurs. Second = Most of the crater is buried in the Gulf of Mexico! Third = Likely caused mega-tsunami reaching US Gulf states. Lastly = Crater estimated to be 150 km in diameter and 30 kilometers deep. Signup and view all the answers

Match to this description!

Asteroid = A rocky or metallic body. Comet = An icy body with glowing tails of gas and dust!! Oort Cloud = A spherical region far from sun where many comets originate!! Kuiper Belt = A region beyond Neptune, containing icy comets. Signup and view all the answers

Match the following related terms!

Significant = Mineral resources! Sudbury Crater = Significant amounts to nickel. May be = Source for life on Earth. Theory = Calls panspermia. Signup and view all the answers

Match the following!

12/72/72 km = Objects enter Earth's atmosphere. Heated = Up due to friction as they fall through Earth's. Airburst = Altitude 5-50! Impact = Ground is a meteorite!! Signup and view all the answers

Match each celestial object with its primary composition:

Asteroid = Rock, metal, or a combination of both Comet = Rocky core surrounded by ice, dust, and gases Meteoroid = Small rock or metallic debris Bolide = Extremely bright meteor Signup and view all the answers

Match the impact consequence with the correct description:

Tsunami = Large ocean waves caused by impacts Wildfires = Fires ignited by superheated debris Earthquakes = Seismic activity caused by impact shockwaves Climate Change = Temporary cooling or long-term warming from dust and gases Signup and view all the answers

Match each meteorite size with its most likely consequence upon entering Earth's atmosphere:

Car-sized = Burns up entirely in the atmosphere House-sized = Explodes with a force greater than the Hiroshima blast Football field-sized = Destroys a city and triggers a significant earthquake Mt. Everest-sized = Creates a massive crater and could cause global extinction Signup and view all the answers

Match the impact crater with its location:

Vredefort Crater = South Africa Chicxulub Crater = Mexico Sudbury Basin = Canada Popigai Crater = Russia Signup and view all the answers

Match the risk mitigation strategy with its description:

Gentle Deflection = Using ion thrusters over long periods to alter trajectory Explosive Deflection = Using nuclear blasts to deflect the object Solar Pressure = Painting one side white to change its orbit Evacuation = Moving populations from projected impact zones Signup and view all the answers

Match the crater with its approximate diameter:

Vredefort Crater = 380 km Chicxulub Crater = 150 km Sudbury Basin = 130 km Popigai Crater = 100 km Signup and view all the answers

Match the term with its correct definition related to the study of near-Earth objects:

Torino Scale = Measures the risk of asteroid impacts Spacewatch = Tracks Earth-crossing objects > 100m in diameter NEAT Project = Detects objects > 1 km Airburst = Explosion of a meteoroid in the atmosphere Signup and view all the answers

Match the impact consequence with its potential long-term environmental effect:

Tsunamis = Coastal erosion and habitat destruction Wildfires = Deforestation and altered ecosystems Earthquakes = Landslides and infrastructure damage Climate Change = Habitat shifts and altered species distribution Signup and view all the answers

Match the event with its primary cause:

Chicxulub Extinction Event = Major meteorite impact Tunguska Event = Airburst of a meteoroid or comet Mass Extinctions = Likely linked to meteorite impacts Sudbury Basin Formation = Ancient meteorite impact Signup and view all the answers

Match the meteorite-related term with its characteristic:

Meteor = Bright streak as a meteoroid enters Earth's atmosphere Meteorite = Meteoroid that survives atmospheric entry and hits Earth Bolide = Extremely bright meteor, often explodes Airburst = MeteoroidExplosion of a meteoroid in the atmosphere Signup and view all the answers

Match each description with the appropriate celestial object:

Asteroid = Primarily found in the asteroid belt between Mars and Jupiter Comet = Believed to originate from the Oort Cloud or Kuiper Belt Meteoroid = Small rock or metallic debris from comets or asteroids Bolide = Often associated with explosions that mimic full moon brightness Signup and view all the answers

Match each potential prevention method for meteorite impacts with its primary mechanism:

Gentle Deflection = Slight, continuous alteration of trajectory using long-term propulsion Explosive Deflection = Immediate change in trajectory through powerful force Solar Pressure = Gradual orbital shift using sunlight Evacuation = Removal of population from at-risk areas Signup and view all the answers

Match each impact crater with its notable feature or impact:

Vredefort Crater = Largest known impact crater on Earth Chicxulub Crater = Linked to the extinction of the dinosaurs Sudbury Basin = Major source of nickel deposits Popigai Crater = Contains diamond formations from impact shock Signup and view all the answers

Match the hazard with the appropriate description:

Tsunamis = Giant waves triggered by underwater or coastal impacts Wildfires = Large-scale fires ignited by superheated ejecta Earthquakes = Seismic disturbances caused by impact shockwaves Volcanic Eruptions = Impact can destabilize the Earth’s mantle, causing eruptions Signup and view all the answers

Match the educational media resource with its most relevant description:

Catastrophe Episode 4 - Asteroid Impact = Scientific investigations into the Chicxulub impact Asteroids to Worry About = Highlights significant asteroids that could pose threats Signup and view all the answers

Match the potential effect of a large meteorite impact with a specific example of how it could manifest:

Tsunamis = Inundation of coastal cities and loss of life Wildfires = Destruction of vast forests and agricultural lands Earthquakes = Collapse of buildings and disruption of infrastructure Climate Change = Global temperature shifts affecting agriculture Signup and view all the answers

Match the monitoring project with its specific objective:

Spacewatch = Tracking Earth-crossing objects larger than 100 meters NEAT Project = Detecting near-Earth objects larger than 1 kilometer Signup and view all the answers

Match each positive aspect of meteorite impacts with an example:

Mineral Resources = Occurrence of nickel deposits in the Sudbury Basin Impact Diamonds = Formation of diamonds in the Popigai Crater Panspermia Hypothesis = Possible origin of life from organic compounds on meteorites Signup and view all the answers

Match the size of a celestial object with the impact energy it could release on Earth, assuming direct impact:

House-sized = Could explode (atmospheric burst) with a force greater than the Hiroshima blast Football field-sized = Could destroy a city (e.g., New York) and trigger a magnitude 7.7 earthquake Mt. Everest-sized = Would create a crater over 160 km wide and likely cause global extinction London-sized = Could potentially change Earth’s orbit Signup and view all the answers

Match each impact site with a delayed or secondary effect that it could plausibly trigger on a global scale:

Ocean Impact = Global tsunamis disrupting coastal ecosystems and human settlements Land Impact in Siberia-like Terrain = Widespread wildfires releasing massive amounts of carbon into the atmosphere Impact Near a Tectonic Boundary = Triggering a cascade of large earthquakes and volcanic eruptions Crater in area rich with Limestone = Acid Rain destroying sensitive environment for decades Signup and view all the answers

Link each potential risk-mitigation strategy against near-Earth objects (NEOs) with its key limitation or challenge in practical application:

Kinetic Impactor Deflection = Requires extremely precise targeting and timing to avoid fragmentation or unintended trajectory changes Nuclear Detonation Deflection = Raises significant ethical, political, and environmental concerns due to nuclear fallout and proliferation risks Gravitational Tractor Method = Needs long lead times (decades to centuries) and a substantial mass ratio between the tractor and the NEO Ion Beam Shepherding = The long exposure time might result in unexpected orbit drifts Signup and view all the answers

Combine each long-term consequence following a significant asteroid impact event with a key secondary stressor that could compound its impact on biodiversity:

Global Impact Winter = Collapse of food chains due to reduced sunlight and photosynthesis Widespread Wildfires = Release of toxic compounds into the atmosphere and soil, further stressing surviving species Acid Rain Events = Disruption of aquatic ecosystems and acidification of soils, affecting plant growth Large-Scale Habitat Loss = Increased competition for resources among remaining organisms, leading to further extinctions Signup and view all the answers

Match the celestial event with its long-term implications for Earth's geological history:

Chicxulub Impact = Potential trigger for the Paleocene-Eocene Thermal Maximum (PETM) and related changes in ocean chemistry Sudbury Basin Formation = Significant alteration of the regional crustal structure and enrichment of valuable mineral deposits Late Heavy Bombardment = Possible delivery of water and organic molecules to early Earth, influencing its habitability Tunguska Event-like occurrences being more common = Deeper changes to the eco-systems in areas that are regularly subjected to such events Signup and view all the answers

Match the potential role of meteorite impacts in the evolution of life with each proposed mechanism.

Delivery of prebiotic molecules = Meteorites could have carried organic compounds from elsewhere in the solar system or beyond Creation of hydrothermal systems = Impact craters could have generated subsurface environments conducive to the origin of life Disruption of existing ecosystems = Impacts could have created opportunities for new species to evolve and diversify Genetic mutations = Extraterrestrial contaminations caused new mutations Signup and view all the answers

Match each aspect of future research and preparedness of impacts with its goals:

Improved Detection = Advanced telescope increases the accuracy of predicting future collisions Global Collaboration = Promoting global effort between military and space agencies Public Awareness = Educating on risks and evacuation process More funding = Securing more funding for better impact prediction Signup and view all the answers

Based on a hypothetical scenario, match each impact-related consequence with its most immediate and devastating effect on a major coastal city such as New York City:

Tsunami Wave Surge = Complete submersion of Lower Manhattan and widespread flooding of subway systems High-Intensity Seismic Shaking = Catastrophic failure of older building structures and collapse of bridges Atmospheric Airburst Shockwave = Shattering of glass windows in all skyscrapers and widespread minor injuries Electromagnetic Pulse (EMP) = Total blackout of the city's power grid and complete communications disruption Signup and view all the answers

Match each proposed method of asteroid deflection with a key factor limiting its feasibility, either in terms of current technology or potential for unintended consequences

Kinetic impactor = Precision required to adjust trajectory rather than fragmenting the object Nuclear blast = Ethical and political concerns about using nuclear weapons in space. Gravitational tractor = Extremely long lead time and precise positioning necessary. Laser ablation = Requires a massive power source and long-term operation Signup and view all the answers

Match each potential effect of an asteroid impact on Earth with a subsequent cascade effect on the biosphere

Global wildfires = Significant drop in atmospheric oxygen levels due to massive consumption of biomass Impact winter = Collapse of photosynthesis and food chains due to reduced sunlight Acid rain = Disruption of aquatic ecosystems and soil composition due to sulfur and nitrogen oxides Tsunamis = Long-term alteration of coastal ecosystems and sediment distribution Signup and view all the answers

Relate aspects of future asteroid impact preparedness with its goals

Enhanced Detection = More accurate tracking of Near-Earth Objects (NEOs) to prevent potential impact Global collaboration = Coordinate efforts to track NEO's Public education = Educating the dangers and increasing awareness of the potential risks Regular space drills = Allowing military and scientists to work together effectively Signup and view all the answers

Connect consequences post asteroid impact, with subsequent stressors effecting biodiversity

Impact Winter = Destruction of habitats Wildfires = Atmosphere filling with toxic compounds like benzene Acid Rain = Soil composition disrupted Habitat destruction = Higher risk of mass extinction and lack of competition to maintain diversity in bio systems Signup and view all the answers

If a large asteroid were to hit Earth, match the consequence, with its short term effect on global population and infrastructure

Tsunamis = Coastal regions will be submerged Wildfires = Infrastructure will be destroyed and mass evacuation will be in order Seismic Shock = Critical infrastructure and buildings will be destroyed Electromagnetic Pulse (EMP) = Complete communication systems will be offline Signup and view all the answers

Based on Tunguska Event, Match subsequent atmospheric and environmental impacts

Atmospheric Shockwave = Large trees are flattened due to air burst creating 50-100m shock of pressure Local forest fires = Biomass is ignited due to debris from burning meteorite Seismic waves = Detected kilometers away due to energy releasing on contact Atmospheric dust and debris = Temporary affects on climate, as a large cloud covers the area Signup and view all the answers

Match each type of meteoroid with it's composition and origin

Stony Meteorites = Silicate minerals and from asteroids Iron Meteorites = Iron-Nickel alloys and core fragments of differentiated asteroids Stony-Iron Meteorites = Silicate and metallic mix from asteroid-mantle boundaries Carbonaceous Chondrites = Hydrated minerals and organic compounds, formed in early solar system Signup and view all the answers

Connect prevention Methods of future impacts and the technical requirements related to implement these methods

Kinetic Impactors = Requires accuracy for targeted deflections to impact the asteroid without causing fragmentation Gravity Tractors = Needs long distances and close proximity to the target for a gravitational pull that alters trajectory Nuclear Detonation = This impact will need to occur a long distance out and requires agreements to use nuclear weapons in space Focused Solar Energy = Will require reflective surface and extended periods of operation in order to work effectively Signup and view all the answers

Relate notable Impact events to fundamental planetary process.

Late Heavy Bombardment = Influenced Earth by bringing water to the planet. Chicxulub impact = Triggered global extinction Tunguska Event = Local Ecological Disturbance that changed forest regions Sudbury Basin Impact = Significant restructuring of Earth's surface and mineral formation Signup and view all the answers

Link future impacts with the economic planning that goes into the creation of safety and security.

Global Tracking System = Allocation of funds towards tracking, analyzing, and categorizing the object. Space drills and Emergency Services = These budgets will need to be increased to train staff and properly perform their duites. Early Detection Warning Systems = Governments will need to have warning systems in place to alert the populaces Research and planning = Creation of safety zones and mitigation Signup and view all the answers

Match asteroid composition that affects planetary evolution and mineral distribution

Carbonaceous Chondrites = Contains water, organic molecules, and amino acids that effects earth Stony asteroids = Delivery of silicate minerals and reshaping of Earth’s crust Iron asteroids = Core composition of early planet causing metal deposits. Metallic asteroids = Create magnetic anomalies, with iron and silicate content Signup and view all the answers

How will the impacts of asteroids in the future change social, political and economy.

Increased funding = Governments will allocate increased funds to national security. Space resources = Asteroid Mining and resource competition across political systems Global migration = Due to habitat destruction, there will have to be large migrations Space Law Development = How future asteroid impacts, and planetary protection will have new rules Signup and view all the answers

Relate the different types of shockwaves with there effects

Planetary scale disruption = Large scale quakes causing entire changes to planetary alignment Ground Shock = Will cause large quakes to the crust Air Blast = Trees can be flattened over large swaths of areas due to pressure Deep Water Shock = Underwater volcano can erupt and cause massive changes to water scales Signup and view all the answers

Relate educational media, with learning and knowledge for asteroid impact events

Documentaries = Educational Insights and visual effects to allow the user to visualize the event Public Forums = Sharing expertise across social classes News and Alerts = Educating on preventative measures and new research. Simulation video = Allowing public to understand the scale of damage Signup and view all the answers

Flashcards

What happens when objects enter earth's atmosphere?

Objects that enter Earth's atmosphere at high speeds and heat up due to friction.

What are Asteroids, Meteoroids and Comets?

Particles grouped by size and composition, ranging from a fraction of a mm to asteroids the size of a small planet.

What are Asteroids?

Space rocks are found in the belt between Mars and Jupiter, composed of rock, metal or a combination.