List Of Asteroid Close Approaches To Earth In 2021 on:
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Below is the list of asteroids that have come close to Earth in 2021.
(size of a person for comparison)
Absolute magnitude 29-30
Absolute magnitude 28-29
Absolute magnitude 27-28
Absolute magnitude 26-27
(probable size of the
Below is an example list of near-Earth asteroids that passed or will pass more than 1 lunar distance (384,400 km or 0.00256 AU) from Earth in 2021.
Timeline of known close approaches less than one lunar distance from Earth
A list of knownnear-Earth asteroid
A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). ...
close approaches less than 1 lunar distance () from Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
in 2021.
For reference, the radius of Earth
Earth radius (denoted as ''R''🜨 or R_E) is the distance from the center of Earth to a point on or near its surface. Approximating the figure of Earth by an Earth spheroid, the radius ranges from a maximum of nearly (equatorial radius, deno ...
is about or 0.0166 lunar distances. Geosynchronous satellite
A geosynchronous satellite is a satellite in geosynchronous orbit, with an orbital period the same as the Earth's rotation period. Such a satellite returns to the same position in the sky after each sidereal day, and over the course of a day tr ...
s have an orbit with semi-major axis
In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the long ...
length of or 0.110 lunar distances.
Warning times by size
This sub-section visualises the warning times of the close approaches listed in the above table, depending on the size of the asteroid. It shows the effectiveness of asteroid warning systems at detecting close approaches in 2021. The sizes of the charts show the relative sizes of the asteroids to scale. For comparison, the approximate size of a person is also shown. This is based theabsolute magnitude
Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...
of each asteroid, an approximate measure of size based on brightness.
Absolute magnitude 30 and greater
(size of a person for comparison)
Absolute magnitude 29-30
Absolute magnitude 28-29
Absolute magnitude 27-28
Absolute magnitude 26-27
(probable size of the Chelyabinsk meteor
The Chelyabinsk meteor was a superbolide that entered Earth's atmosphere over the southern Ural (region), Ural region in Russia on 15 February 2013 at about 09:20 Yekaterinburg Time, YEKT (03:20 Coordinated Universal Time, UTC). It was caused ...
)
Absolute magnitude 25-26
Absolute magnitude less than 25 (largest)
Predicted close approaches
Below is the list of predicted close approaches ofnear-Earth asteroid
A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). ...
s larger than magnitude
Magnitude may refer to:
Mathematics
*Euclidean vector, a quantity defined by both its magnitude and its direction
*Magnitude (mathematics), the relative size of an object
*Norm (mathematics), a term for the size or length of a vector
*Order of ...
27, that were predicted to occur in 2021.Absolute magnitude
Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...
27 is the estimated magnitude of the Chelyabinsk meteor
The Chelyabinsk meteor was a superbolide that entered Earth's atmosphere over the southern Ural (region), Ural region in Russia on 15 February 2013 at about 09:20 Yekaterinburg Time, YEKT (03:20 Coordinated Universal Time, UTC). It was caused ...
, which caused widespread damage and injury, but no deaths. Objects smaller than this are excluded. This relates to the effectiveness of asteroid cataloging systems at predicting close approaches in 2021. (with a 9 day observation arc from January 2018) could have passed as far as from Earth.
For asteroids which were observed but not predicted in advance, see the main list above.
Notes
Additional examples
Below is an example list of near-Earth asteroids that passed or will pass more than 1 lunar distance (384,400 km or 0.00256 AU) from Earth in 2021.
Notes
See also
*List of asteroid close approaches to Earth
This is a list of examples where an asteroid or meteoroid travels close to the Earth. Some are regarded as potentially hazardous objects if they are estimated to be large enough to cause regional devastation.
Near-Earth object detection technol ...
*List of asteroid close approaches to Earth in 2020
Below is the list of asteroid close approaches to Earth in 2020.
Timeline of known close approaches less than one lunar distance from Earth
A list of known near-Earth asteroid close approaches less than 1 lunar distance () from Earth in ...
*List of asteroid close approaches to Earth in 2022
Below is the list of asteroids that have come close to Earth in 2022.
Timeline of known close approaches less than one lunar distance from Earth
A list of known near-Earth asteroid close approaches less than 1 lunar distance () from Earth ...
*Asteroid impact prediction
Asteroid impact prediction is the prediction of the dates and times of asteroids impacting Earth, along with the locations and severities of the impacts.
The process of impact prediction follows three major steps:
# Discovery of an asteroid and ...
References
{{2021 in space * * close approaches to Earth in 2021 Near-Earth asteroids