Earth is now in "opposition" - the precise opposite sides of our planet to the sun. The two planets will be just 57.6 million kilometres apart.
It means the Red Planet will appear super bright, and with its orange-red color, will be hard to miss in the nighttime sky.
At 3:50 a.m. EDT (0750 GMT), Mars reached the closest point to Earth in its orbit.
But, when and where can I see it?
What defines a "close approach?".
Astronomers are interested in Mars' travel path because it helps decide the best times for spacecraft to launch. Those who were watching the lunar eclipse on July 27 must have noticed Mars in the sky too, as the planet was easily visible a few degrees below our natural satellite.
In the summer of this year there are worthy of the attention of astronomical events - the opposition of Saturn and then Mars to our planet. The next close approach, meanwhile, in 2020, will be 38.6 million miles (62 million kilometers), according to NASA.
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As there will be other planets in good position for viewing at that time, there will also be telescopes set up on the UA Mall directed at Venus, Jupiter, Saturn and the Moon run by volunteers from Mt. Lemmon SkyCenter and Tucson Amateur Astronomy Association.
It was also recently discovered that water was found on the surface of Mars.
Mars will appear brighter and bigger in our night sky tonight, July 31, because of a rare occurrence called Mars Close Approach.
Although people viewing Mars from low latitudes and from the Southern Hemisphere will have the clearest view of the the Red Planet, Mars will be visible worldwide.
NASA estimates the 2003 "opposition" was the closest approach by Mars in nearly 60,000 years. NASA said that the planets won't be rubbing shoulders that closely again until 2287. In the evening, half-an-hour after sunset, looking towards the sky opposite direction to sunset, one can spot planet Mars between East and South East direction.
Observatories across the United States are hosting Mars-viewing events right now.
Earth's neighboring planet, Mars, is closer than it has been in the past 15 years, offering unusually bright views of the Red Planet's auburn hues. Mars's next close approach is October 6, 2020.