MARCH is going to be asteroid month. Four asteroids will whizz past the Earth (hopefully) over the next few weeks - although Nasa says we have nothing to fear.

One of the asteroids - EH17 - is as big as a jumbo jet, and will be the biggest of the so-called potentially hazardous objects (PHOs) to make “relatively close approaches” to our planet this month.

NASA's Centre for Near-Earth Object Studies (CNEOS) in California keeps a watching brief on potential threats.

And the next asteroid to soar through our skies will come within 2.6 million miles on Tuesday, according to experts. That may sound a long way off, but it is actually pretty close in astronomical terms.

EH17 measures 130 feet across and is being tracked because it meets strict criteria on asteroids that are deemed a risk to earth set by CNEOS.

Any approaches of an asteroid or comet of about 500 feet in size, or which come within 4.6 million miles – around 20 times the distance to the moon – is termed a potentially hazardous object.

These giant rocks from outer space zoom past Earth far more frequently than many people realise.

The day after EH17’s appearance, another object almost twice the size will pass Earth within 3.9 million miles.

Then, on March 8, we may actually be able to see TX68 as it comes within 3.1 million miles of Earth – although it was initially thought it would come much closer.

Scientists who monitor these objects are constantly revising and updating data. Last week it was predicted that TX68’s flypast could be anywhere between 11,000 and nine million miles away. A figure of 11,000 miles in astronomical terms is the equivalent to a bullet flying past your ear.

“This asteroid’s orbit is quite uncertain, and it will be hard to predict where to look for it,” said Paul Chodas, manager of CNEOS.

“There is a chance that the asteroid will be picked up by our asteroid search telescopes when it safely flies past us next month, providing us with data to more precisely define its orbit around the sun.”

Two years ago it flew past Earth at a comfortable distance of about 1.3 million miles and it was thought it may do so again on March 5.

But that date has since been moved to March 8 and the distance from earth revised to 3.1million miles.

Chodas said: “We already knew this asteroid, 2013 TX68, would safely fly past Earth in early March, but this additional data allow us to get a better handle on its orbital path.

“The data indicate that this small asteroid will probably pass much farther away from Earth than previously thought.”

Asteroid 2013 TX68 is estimated to be about 100 feet in diameter. By comparison, the asteroid that broke up in the atmosphere over Chelyabinsk, Russia, three years ago was approximately 65 feet wide.

If an asteroid the size of TX68 were to enter Earth's atmosphere, it would likely produce an air burst with about twice the energy of the Chelyabinsk event. But Chodas insisted “there is no concern whatsoever”.

He said: “Prospects for observing this asteroid, which were not very good to begin with, are now even worse because the asteroid is likely to be farther away, and therefore dimmer than previously believed.”

New observations can now better constrain the path of the asteroid in years to come and CNEOS has determined that it cannot impact Earth over the next century.

Orbit calculations of asteroids are constantly updated based on observations reported to the Minor Planet Center.

This results in projections of minimum, maximum and nominal distances from Earth, which can sometimes have a wide disparity due to limited data.

Over time, with additional observations added to the equation, scientists are able to refine and narrow the orbit uncertainties.

Experts have identified an extremely remote chance that this small asteroid could impact on September 28, 2017, with odds of no more than 250 million to one. Fly-bys in 2046 and 2097 have an even lower probability of impact.

“The possibilities of collision on any of the three future fly-by dates are far too small to be of any real concern,” Chodas added. “I fully expect any future observations to reduce the probability even more.”

However, there are many other asteroids which will be in closer proximity to Earth in the coming weeks and months.

One to watch is FX9 which is due to flypast at a distance of only 1.6 million miles from us on March 19.