How do asteroids travel in space?

Could we alter an asteroids course if it were to collide with earth?

 

WHAT ARE ASTEROIDS?

• Asteroids are rocks revolving around the sun that aren’t big enough to be called planets.
• The current known asteroid count is: 779,938
  They range in size from hundreds of kilometers to many meters across. The mass of all the asteroids is less than that of Earth’s moon

Disregarding an asteroid’s size, they can be very dangerous. Many have hit Earth in the past, and scientists suspect that more will crash into our planet in the future. FORMATION AND PHYSICAL CHARACTERISTICS:

• Asteroids are leftovers from the formation of our solar system about 4.6 billion years ago
• The birth of Jupiter didn’t’t allow any planets to forming in the gap between Mars and Jupiter, resulting in the small objects that collided with each other and fragmented into the asteroids seen today
• Most asteroids are irregularly shaped, but a few are nearly spherical. They are often pitted or cratered

Asteroids can reach as large 940 kilometers across. The smallest asteroid ever studied is the 2 meter wide space rock 2015 TC25 which was observed when it made a close flyby of Earth in October 2015.CLASSIFICATION:

• The three broad composition classes of asteroids are C-, S-, and M-types:
• The C-type (chondrite) –  most common, consist of clay and silicate rocks, and are dark in appearance. They are among the most ancient objects in the solar system.

  The S-types (“stony”) – made up of silicate materials and nickel-iron.

  The M-types are metallic (nickel-iron). – compositional differences are related to how far from the sun they formed. Some experienced high temperatures after they formed and partly melted, with iron sinking to the center and forcing lava to the surface.

TRAVEL:

• Jupiter’s massive gravity and occasional close encounters with Mars or another object can change an asteroids’ orbits, causing them to be knocked out of the main asteroid belt and hurling them into space in any directions through the orbits of the other planets.
• Radar is an important tool in detecting and monitoring potential impact hazards. By reflecting transmitted signals off objects, images and other information can be derived from the echoes. Scientists can learn a great deal about an asteroid’s orbit, rotation, size, shape, and metal concentration.

ASTEROID DEFENSE:

• NASA has a Planetary Defense System to work against asteroids:

Planetary defense is the term used to include all the capabilities that are needed to detect the possibility and warn of potential asteroid or comet impacts with Earth, and then either prevent them or mitigate their possible effects.

1. Finding/tracking near-Earth objects that pose of hazard of impacting Earth
2. Characterizing objects to determine their orbit trajectory, size, shape, mass, composition, rotational dynamics and other parameters, so experts can determine how severe the potential impact event, warn of its timing and potential effects, and determine the means to mitigate the impact; and
3. Planning/implementation of measures to deflect or disrupt an object on an impact course with Earth, or to mitigate the effects of an impact that cannot be prevented. Mitigation measures that can be taken on Earth to protect lives and property include evacuation of the impact area and movement of critical infrastructure.

• Radar is a valuable tool in detecting and monitoring potential impact hazards. By reflecting transmitted signals off objects, images and other information can be derived from the echoes. Scientists can learn a great deal about an asteroid’s orbit, rotation, size, shape, and metal concentration.

• Would it be possible to shoot down an asteroid that is about to impact Earth?

An asteroid on a trajectory to impact Earth could not be shot down in the last few minutes or even hours before impact.  No known weapon system could stop the mass because of the velocity at which it travels – an average of 12 miles per second. 

• How can we prevent an asteroid impact with Earth?

1. Deploy a more extensive asteroid observation network, using ground-based and space-based assets, to complete the survey of the NEO population. The combined efforts of space-based and ground-based observation assets are key to detecting and characterizing newly found NEOs.  Equally important to initial detection are follow-up observations for precision orbit determination and physical characterization to determine the size and composition of the object.
2. Find any potential threat as early as possible. With a couple of decades of warning, which would be possible for 100-meter-sized asteroids with a more capable detection network, several options are technically feasible for preventing an asteroid impact.
3. Deflecting an asteroid that is on an impact course with Earth requires changing the velocity of the object by less than an inch per second years in advance of the predicted impact.

The two most promising techniques that NASA is investigating are:

the kinetic impactor – hitting an asteroid with an object to slightly slow it down

the gravity tractor- gravitationally tugging on an asteroid by station-keeping a large mass near it

• So, When Will We Be Able To Prevent an Asteroid Collision?