Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

European Space Agency to probe asteroid blind spot

15.04.2002


Artist’s impression on an asteroid impact with the Earth
® ESA


In the past five weeks two asteroids have passed close by Earth, at distances of 1.2 and 3 times the distance to the Moon. Another asteroid has recently been shown to be on course for a collision with Earth in 2880.

Monitoring known asteroids allows astronomers to predict which may collide with Earth. But that is only true for the asteroids we know of. What about those that lie in the asteroid blind spot between the Sun and Earth? The European Space Agency is studying ways in which its missions can assist in monitoring these unseen but potentially hazardous asteroids.
It is difficult to estimate the danger posed by asteroids. This is, in part, because astronomers do not yet know how many asteroids there are. A recent discovery, made using data from ESA`s Infrared Space Observatory (ISO), showed that there could be nearly two million asteroids larger than one kilometre in the main asteroid belt, between Mars and Jupiter. That is more than twice as many as previously thought.


In addition, even when an asteroid is identified many observations must be made before it is known whether or not it will come close to, or even collide with, Earth.

If the asteroids remained in the main-belt, they would pose no danger to Earth. However, they can be thrown into different orbits by collisions with other asteroids or by the influence of Jupiter`s gravitational field. If their new orbits cross the Earth`s orbit, they could one day collide with our planet, inflicting unprecedented devastation.

A number of ground-based searches are already underway to find as many potentially hazardous asteroids (PHAs) as possible but there is a notorious `blind spot` that telescopes on Earth can never peer into. It is the region of space inside Earth`s orbit, towards the Sun. From Earth, astronomical observations close to the Sun are almost impossible because it means observing during the daytime when only the brightest celestial objects stand out from the blue sky. That means asteroids lurking in this region of space can `sneak up` on the Earth undetected. Asteroid 2002 EM7, which passed close by the Earth on 8 March this year, was one such object and was only detected after it crossed Earth`s orbit to appear briefly in the night sky, before it crossed back into the glare of the Sun.

About 550 similar asteroids are known. They are called the Atens and spend most of their time inside Earth`s orbit, close to the Sun. Traditional estimates suggest there may be several thousand in total and tracking them from Earth is next to impossible. However, a study performed for ESA has shown that the Gaia spacecraft will be able to see clearly into this `blind spot` and keep precise track of the Aten population.

François Mignard of Observatoire de la Côtes d`Azur, France, conducted the study. He found that Gaia would be ideal because it is designed to measure the position of celestial objects with unprecedented accuracy. In addition, since there is no atmosphere in space to scatter the Sun`s rays and create a blinding blue sky, Gaia can see close to the Sun without disturbance.

Gaia is expected to be launched around 2010. Even if ground-based searches have spotted more Atens by that time, the mission still has an essential role to play because it will reveal their orbits to a precision 30 times better than any observation from the ground, thus identifying whether any pose a danger to Earth.

"To know how close these objects will come to Earth is very dependent on how accurately one can measure their orbits. That`s the main contribution that Gaia can be expected to make," says Michael Perryman, project scientist for Gaia, at ESA`s European Space Research and Technology Centre in the Netherlands.

Gaia`s data will also provide astronomers with a first estimate of these objects` composition. This knowledge could help to determine methods to divert or destroy asteroids that are set on a collision course with Earth.

Several ESA missions are contributing, or will contribute, to our understanding of minor bodies of the Solar System: these include ISO, Gaia and Rosetta, which will study asteroids Siwa and Otawara. ESA is also considering the addition of an asteroid spotting telescope to its BepiColombo mission.

Monica Talevi | alphagalileo
Further information:
http://www.esa.int/export/esaCP/ESA93VF18ZC_index_0.html

More articles from Physics and Astronomy:

nachricht New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center

nachricht Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Symposium on Driving Simulation

23.10.2017 | Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

 
Latest News

Did you know how many parts of your car require infrared heat?

23.10.2017 | Automotive Engineering

3rd Symposium on Driving Simulation

23.10.2017 | Event News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>