Posted on by Matt Williams

NASA Launches DART, to Learn how to Defend the Earth From a Future Asteroid Impact

The SpaceX Falcon 9 rocket launches with the Double Asteroid Redirection Test, or DART, spacecraft onboard, Tuesday, Nov. 23, 2021, Pacific time (Nov. 24 Eastern time) from Space Launch Complex 4E at Vandenberg Space Force Base in California. DART is the world’s first full-scale planetary defense test, demonstrating one method of asteroid deflection technology. The mission was built and is managed by Johns Hopkins APL for NASA’s Planetary Defense Coordination Office. Photo Credit: (NASA/Bill Ingalls)

In the early hours of the morning on Wednesday, Nov. 24th, NASA’s Double Asteroid Redirection Test (DART) launched from Space Launch Complex 4 East at Vandenberg Space Force Base (SFB) in California. This spacecraft is the world’s first full-scale mission to demonstrate technologies that could someday be used to defend our planet from Near-Earth Asteroids (NEAs) that could potentially collide with Earth.

Put simply, the DART mission is a kinetic impactor that will evaluate a proposed method for deflecting asteroids. Over the next ten months, the DART mission will autonomously navigate towards the target asteroid – the binary NEA (65803) Didymos – and intentionally collide with it. If everything goes according to plan, this will alter the asteroid’s motion so that ground-based telescopes can accurately measure any changes.

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Posted on by Jerry Coffey

What Is Mechanical Energy

Millennium Force roller coaster Credit: Cedar Point
Millennium Force roller coaster Credit: Cedar Point

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The straight forward answer to ‘what is mechanical energy’ is that it is the sum of energy in a mechanical system. This energy includes both kinetic energy(energy of motion) and potential energy(stored energy).

Objects have mechanical energy if they are in motion and/or if they are at some position relative to a zero potential energy position. A few examples are: a moving car possesses mechanical energy due to its motion(kinetic energy) and a barbell lifted high above a weightlifter’s head possesses mechanical energy due to its vertical position above the ground(potential energy).

Kinetic energy is the energy of motion. An object that has motion, vertical or horizontal motion, has kinetic energy. There are many forms of kinetic energy: vibrational (the energy due to vibrational motion), rotational (the energy due to rotational motion), and translational (the energy due to motion from one location to another).

Potential energy is the energy stored in a body or in a system due to its position in a force field or its configuration. The standard unit of measure for energy and work is the joule. The term “potential energy” has been used since the 19th century.

Because of the different components of mechanical energy, it exists in every system in the universe. From a baseball being thrown to a brick falling off of a ledge, mechanical energy surrounds us. Defining what is mechanical energy is easy, but finding examples of it are even easier.

We have written many articles about mechanical energy for Universe Today. Here’s an article about how generators work, and here’s an article about what is energy.

If you’d like more info on Mechanical Energy, check out a Discussion on Energy, and here’s a link to an article about Momentum.

We’ve also recorded an entire episode of Astronomy Cast all about Gravity. Listen here, Episode 102: Gravity.