Bennu asteroid animation reveals ambitious Osiris-Rex mission to collect samples
comments
For millions of years, asteroid Bennu has been assaulted by the gravity of planets as it hurtles through space.
Now a new animation, dubbed 'Bennu's Journey', follows the rough life of the asteroid and how it could reveal the origin of the solar system.
It also depicts the Osiris-Rex mission, which will be launched in late 2016, arrive at the asteroid Bennu in 2018, and return a sample of Bennu's surface to Earth five years later.
Scroll down for video
This is an artist's concept of the impact that created the asteroid Bennu. Scientists think Bennu formed when some of the rubble from a collision like this coalesced under its own gravity
The Nasa video follows the success of Esa's Rosetta mission, which last week captured the imagination of the public after it made a successful landing on a comet.
Unlike comets, which are made up of ice, dust and rocky material, asteroids contain metals from when the solar system as first formed.
Share this article
'We are going to Bennu because we want to know what it has witnessed over the course of its evolution,' said Edward Beshore of the University of Arizona.
'Bennu's experiences will tell us more about where our solar system came from and how it evolved,' said Professor Beshore.
An artist's concept of the young Earth being bombarded by asteroids. Scientists think these impacts could have delivered significant amounts of organic matter and water to Earth
'Like the detectives in a crime show episode, we'll examine bits of evidence from Bennu to understand more completely the story of the solar system, which is ultimately the story of our origin.'
This mission is a precursor to a bigger mission, where Nasa will attempt to capture an asteroid and bring it into the moon's orbit.
The video opens with an establishing shot of the galaxy and moves in to a nebula - a vast cloud of gas and dust ejected from the explosions of dying stars.
From observations of other star-forming regions in our galaxy, scientists have a good idea of the basic outlines of how our solar system came to be, according to Professor Beshore.
The animation shows a star disrupting material in the nebula, causing part of it to collapse under its own gravity and form a disk of material surrounding the infant sun.
'We are going to Bennu because we want to know what it has witnessed over the course of its evolution,' said Edward Beshore of the University of Arizona. Pictured is a concept image of asteroids being pulled in by the gravity of a planet
This is a conceptual image of a nebula. Nebulas are vast clouds of gas and dust ejected from the explosions of dying stars. Scientists think the solar system formed when a nearby exploding star disrupted material in a nebula, causing part of it to collapse under its own gravity
Within this disc, bits of dust are flash heated to molten rock and solidify to become chondrules - some of the building blocks of the solar system.
Chondrules are shown in the animation as they clump together via electrostatic and gravitational forces to become asteroids and planets. They also may make up a large part of the material in Bennu.
'On planets like Earth, the original materials have been profoundly altered by geologic activity and chemical reactions with our atmosphere and water,' said Professor Beshore.
'We think Bennu may be relatively unchanged, so this asteroid is like a time capsule for us to examine'.
By studying the sample collected from Bennu, the Nasa team will be able to examine some of the most pristine material to be found in the solar system.
Bennu may also harbour organic material, which could give scientists an inventory of the materials present at the beginning of the solar system.
Unlike Esa's Philae probe, which can only study comet material onsite, the Osiris-Rex will bring the material back to Earth.
'By bringing this material back to Earth, we can do a far more thorough analysis than we can with instruments on a spacecraft, because of practical limits on the size, mass, and energy consumption of what can be flown,' said Professor Beshore.
'We will also set aside returned materials for future generations to study with instruments and capabilities we can't even imagine now.'
The early solar system is thought to have been chaotic. Giant impact craters throughout the inner solar system indicate there may have been a 'late heavy bombardment' by asteroids around 4.1 billion to 3.8 billion years ago, right around the origin of life on Earth.
The video shows one theory for this. The massive 'gas giant' planet Jupiter began to migrate inward closer to the sun due to gravitational interactions with the outer gas giant planets.
Jupiter's gravity disrupted the asteroid belt, tossing many asteroids closer to the sun, where some collided with the terrestrial planets, including Earth.
This asteroid bombardment may have been a significant source of organic matter and water for the early Earth.
By studying the sample collected from Bennu, the Nasa team will be able to examine some of the most pristine material to be found in the solar system. Pictured is an artist's impression of an impact on Jupiter's moon, Europa
After this bombardment, things calmed down a little, but massive collisions still happened occasionally, like the one the video shows happening between an asteroid and a planet about one billion years ago.
Scientists think a collision like this may have resulted in the birth of Bennu and the video illustrates the asteroid forming as some of the rubble from the collision slowly coalesces under its own weak gravity.
Measurements reveal that Bennu's density is less than that of rock, so scientists think the asteroid may have voids in its interior, according to Beshore.
An asteroid like this is called a 'rubble pile' -- a loosely bound collection of boulders, rock, and dust.
Bennu is also quite dark. Like an asphalt road on a hot day, it absorbs most of the sunlight that hits it and later radiates this energy away as heat.
This radiation gives Bennu a tiny push, called the Yarkovsky effect, which gradually changes its orbit over time.
The animation shows how the Yarkovsky effect causes Bennu to migrate until it encounters a so-called gravitational resonance with the planet Saturn.
Regular tugs by this resonance eventually push Bennu into the inner solar system, where it has repeated close encounters with Venus and Earth.
These encounters pull apart the rubble pile that is Bennu, turning it inside out and reshaping the asteroid.
Because Bennu comes close to Earth, there is a tiny chance – about 1 in 2,500 – that it could hit Earth late in the 22nd century, according to Professor Beshore.
'We'll get accurate measurements of the Yarkovsky effect on Bennu by precisely tracking Osiris-Rex as it orbits the asteroid,' he added.
Pictured is an artist's concept of Nasa's Osiris-Rex asteroid-sample-return spacecraft arriving at the asteroid Bennu. Because Bennu comes close to Earth, there is a tiny chance – about 1 in 2,500 – that it could hit Earth late in the 22nd century, according to Professor Beshore
Put the internet to work for you.
0 comments:
Post a Comment