July, 2014Archive for

Superlative Chapter 2: The Fastest…

Thursday, July 31st, 2014

In the first edition of the Superlative series, we looked at the biggest things in the universe. Today we’ll explore another extreme – the fastest objects known.

Fastest Galaxy

The question of the fastest moving galaxy relative to us is not an easy one to answer. Because of the expanding universe, the speed at which distant galaxies are receding from our location is mostly due to the actual stretching of space. Thus, the further the galaxy from us, the further it is moving away from us.

Currently, the fastest known celestial object moving away from us is the primordial galaxy known as UDFy-38135539. It is also the furthest galaxy we have ever observed, at approximately 13.1 billion light years. This means UDFy-38135539 formed in the first 700 million years of the universe’s existence.

Infrared glow from the bow shock

Fastest Star

Recently, a number of new hypervelocity stars have been discovered in the Milky Way. These are stars that travel at more than two million miles per hour. The fastest of which is the star known as Kappa Cassiopeiae. It is traveling at 2.5 million miles an hour, and is at a distance of about 4000 light years from earth. Not to worry, Even if Kappa Cassiopeiae, which exists in the Cassiopeiae constellation, were heading directly for Earth, it still would take approximately 1.1 million years to reach our solar system.

Interestingly, hypervelocity stars such as Kappa Cassiopeiae impact the space in front of their direction of travel so much, that the interaction between the star’s magnetic field and the matter in space creates a large infrared glow. This phenomenon is known as a bow shock, and it can affect space up to four light years ahead of the star itself.

Artist’s rendition of VFTS 102

Fastest Rotating Object

The fastest rotating celestial body discovered to date does not exist in the Milky way, but rather a smaller galaxy approximately 160,000 light years away, known as the Large Magellanic Cloud. This star, known as VFTS 102, is about 25 times more massive than the sun, and was thought to be ejected from a binary star system. At its surface, it rotates at approximately 1 million miles an hour; about 100 times faster than our sun.

Fastest Planets

The fastest moving planet in our own solar system is Mercury. It has an orbital period (year) of just 88 Earth days, and moves through space relative to the sun at 107,700 mph. This is nearly double the 67,100 mph the Earth averages in it’s orbit around the sun.

As in most cases, exoplanets are far more extreme than our own solar system. Kepler 70b, for instance, has an orbital period of only 5.76 hours, giving it an orbital velocity of more than 375,000 mph.

Artist’s rendition of the Solar Probe Plus, set to launch in 2018

Fastest unmanned object

The current fastest man made object to exist was the Helios II probe launched on January 15th, 1976. It was put into orbit around the sun just inside the orbit of Mercury. At it’s nearest point (known as perihelion), it recorded a top speed of 157,078 miles per hour.

In the near future, the Juno probe which is set to visit Jupiter, will accelerate to 165,000 mph by using Earth’s gravity. Additionally, the Solar Probe Plus, set to launch in 2018, will take it on a similar mission as the Helios probe to study the sun. The probe is expected to reach speeds in excess of 450,000 mph, nearly three times the current record.

Fastest manned object

The fastest manned spacecraft, and thus the fastest humans have ever traveled relative to the Earth, was the Apollo 10 command module, on May 26th, 1969. This spacecraft was used for final testing in lunar orbit before Apollo 11 landed on the Moon. On its return flight home, it achieved a speed of 24,791 mph.