Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mars will be at its closest to Earth for almost 60,000 years

21.07.2003


On 27th August, Mars will be at its closest to Earth for almost 60,000 years. On that date, the Red Planet will approach to within 34,646,418 miles (55,758,006 km) - 145 times the distance of the Moon.

The last time the two planets were so close our ancestors were living in caves and struggling to survive the extreme conditions of the Ice Age. Who knows what will have happened by the time they are as near again - 284 years into the future?

When and were to see Mars



Mars is now in the constellation Aquarius and is readily recognised because it is already the brightest object in the night sky (apart from the Moon). Instantly recognisable by its brilliance and orange-red colour, it will remain easy to spot for several months, low in the sky somewhere between the southeast and the southwest. (Exactly where depends on the date and time.)

Currently, Mars rises at about 11 pm (BST) but it comes up a few minutes earlier each night. Future rising times are 10 pm on 7 August, 9 pm on 21 August and 8 pm on 4 September. About 5 hours after it has risen, Mars reaches its highest point above the horizon - an altitude of about 23 degrees as seen from London - and lies due south.

Brighter than the Stars

At its peak brightness, Mars will reach magnitude -2.9, far outshining the brightest star, Sirius (magnitude -1.5). It will remain brighter than Sirius until mid-October. Venus is the only planet that can appear brighter, but Venus will not be visible again until December.

The closest of close encounters

Earth and Mars are rather like two runners going around a racetrack in lanes at different speeds. Mars travels around the Sun about one and a half times farther away than Earth on average and takes 687 days to make a circuit compared with Earth’’s 365 days. Roughly every 26 months, Earth overtakes Mars on the inside. When this happens, there’’s a close encounter between Earth and Mars and the two planets line up in space with the Sun. This orbital rendezvous is called an OPPOSITION of Mars, because the Sun and Mars are on opposite sides of Earth.

If the orbits of Earth and Mars were circles, Mars would be the same distance from Earth at every opposition. But the orbits are actually ellipses (oval-shaped), with the Sun offset from the centre. Mars, more so than Earth, follows a very non-circular orbit, so its distance from the Sun varies by 26.5 million miles (42.4 million km). This means that the distance between Earth and Mars at an opposition can be anything between about 35 million miles (56 million km) and 63 million miles (100 million km).

Because Mars’’s orbit is so elliptical, the time when Mars and Earth are closest and the actual opposition - when Sun, Earth and Mars are in a direct line - do not quite coincide. This year’’s opposition is on 28 August, a day later than closest approach.

Every 15 - 17 years, there is an opposition of Mars when the Red Planet is not far from its closest point to the Sun - its ’’perihelion’’.

Taking a closer look

Mars is a small planet, roughly half the size of Earth. At its closest, it appears little more than half the size of Jupiter, or similar in size to a large crater on the Moon.

To see markings on its surface, you ideally need at least a 6 inch (15 cm) telescope. With a magnification of 40 when at its closest, Mars would appear about the same size as an orange seen with the naked eye across the length of a tennis court. You could see it was an orange but that’’s about all - it would be quite small.

To see any markings and the famous polar ice caps, a higher magnification is needed, if the telescope is good enough. Unfortunately, detailed observing will not be very easy from the UK at this opposition because Mars is so low in the sky.

It is now spring in Mars’’s southern hemisphere and the ice cap at the south pole is tilted towards Earth. As the atmosphere warms and the thin air begins to stir, dust storms frequently occur. Huge storms can sometimes shroud large areas of the planet, hiding the giant volcanoes and other surface features.

Memorable Mars Minutiae

  • In Assyria, Mars was known as the "Shedder of Blood". The Red Planet also represented the god of war for the Vikings, the Greeks and the Romans.

  • The red colouration of Mars is due to oxidised iron minerals in the surface rocks - rust.

  • Mars is considerably smaller and less massive than Earth so its surface gravity is only one third of that on our planet. An astronaut weighing 60 kg on Earth would only weigh 20 kg on Mars.

  • The surface area of Mars is approximately the same as the land area of Earth.

  • A Martian day (known as a ’’sol’’) lasts for 24 hours 37 minutes - only a little longer than a day on Earth.

  • After Italian astronomer Giovanni Schiaparelli announced the discovery of "canali" (channels) on Mars in 1877, there was intense speculation that intelligent life existed on the planet. Their existence was not disproved until the first spacecraft visited Mars in the early 1960s.

  • An Orson Welles radio presentation of The War of the Worlds, broadcast in 1938, caused widespread panic in America when listeners believed that a Martian invasion had begun.

  • Mars approaches closer to Earth than any of the other planets apart from Venus.

  • The air pressure on Mars is less than 1% of that on Earth - equivalent to the air pressure at an altitude of 30 km above the Earth’’s surface. As a result, liquid water immediately sublimates (changes to a gas) on reaching the surface.

  • The polar caps of Mars contain both water ice and dry ice (frozen carbon dioxide).

  • Mars has two small moons: Phobos (fear) and Deimos (panic), which are thought to be captured asteroids. Although they were discovered by American astronomer Asaph Hall in 1877, they were ’’predicted’’ 150 years earlier in Swift’’s novel Gulliver’’s Travels.

  • Unlike Earth’’s Moon, Phobos and Deimos are too small to completely block the Sun when they pass in front of it, but they do cast a shadow over the Martian surface.

  • Two NASA orbiters (Mars Global Surveyor and Mars Odyssey) are currently mapping Mars. Five more spacecraft are en route to the Red Planet: the Mars Express orbiter (the European Space Agency’’s first planetary mission), the British-led Beagle 2 lander (the first UK-built spacecraft to land on another world), the Nozomi orbiter (Japan’’s first planetary probe), and two NASA rovers (Spirit and Opportunity).

  • NASA’’s Mars Pathfinder rover mission, which landed on 4 July 1997, was one of the most popular events in Internet history. A total of 566 million "hits" was registered on NASA’’s Pathfinder Web sites during the first month on Mars, with 47 million hits on 8 July alone.

  • Scientists have found over 20 meteorites that have come from Mars. They seem to have been blasted out of Mars by large asteroid impacts, then spent millions of years travelling through space before they landed on Earth. Some scientists claim that they have found evidence of primitive microbial life in several of these meteorites.

Dr. Jacqueline Mitton | alfa
Further information:
http://www.astronomyweek.org.uk
http://www.britastro.com/mars
http://science.nasa.gov/headlines/y2003/18jun_approachingmars.htm

More articles from Physics and Astronomy:

nachricht Gamma rays will reach beyond the limits of light
23.10.2017 | Chalmers University of Technology

nachricht Creation of coherent states in molecules by incoherent electrons
23.10.2017 | Tata Institute of Fundamental Research

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: Salmonella as a tumour medication

HZI researchers developed a bacterial strain that can be used in cancer therapy

Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...

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...

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

Microfluidics probe 'cholesterol' of the oil industry

23.10.2017 | Life Sciences

Gamma rays will reach beyond the limits of light

23.10.2017 | Physics and Astronomy

The end of pneumonia? New vaccine offers hope

23.10.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>