Big asteroid to flyby Earth on September 1
NASA says asteroid 2.7 miles wide will make ‘relatively close encounter with our planet’
Similar exoplanet could exist in habitable zone of nearby star system just 16 light-years away
A massive asteroid estimated to be 2.7 miles wide is set to make a ‘relatively close encounter’ with Earth on September 1, 2017.
Dubbed “Florence,” the huge space rock will pass just 4.4 million miles from our planet – or, about 18 times the distance between Earth and the moon.
According to the United States National Aeronautic Space Agency (NASA), this is the closest an asteroid of this size has come since they first began tracking near-Earth objects, giving scientists an unprecedented opportunity to study it up close through ground-based radar observations.
Asteroid Florence was first spotted in 1981, and is estimated to be 2.7 miles (4.4 kilometers) wide.
It will fly past Earth at a distance of about 4.4 million miles (7 million kilometers), or about 18 Earth-moon distances.
This is the closest an asteroid this large has come since NASA began its Near Earth Object (NEO)-tracking programme.
The flyby in September will be the closest it has come to Earth since 1890. And, it would not come this close again until 2,500.
While it may sound alarming, NASA says asteroid Florence will safely fly past Earth at a distance of about 4.4 million miles (7 million kilometers).
It is not the closest encounter our planet has seen with an NEO, but for this distance, the experts say it is the largest.
“While many known asteroids have passed by closer to Earth than Florence will on September 1, all of those were estimated to be smaller,” said Paul Chodas, manager of NASA’s Center for Near-Earth Object Studies (CNEOS) at the agency’s Jet Propulsion Laboratory.
“Florence is the largest asteroid to pass by our planet this close since the NASA program to detect and track near-Earth asteroids began.”
The asteroid, named for Florence Nightingale, was first spotted in 1981, and the flyby in September will be the closest it is come to Earth since 1890. And, it won’t come this close again until 2,500.
According to NASA, it will even be visible to small telescopes in late August and early September, when it brightens to the ninth magnitude. During this time, it will pass through the constellations Piscis Austrinus, Capricornus, Aquarius and Delphinus.
NASA scientists will use ground-based radar to observe its features up close, using radar imaging NASA’s Goldstone Solar System Radar in California and at the National Science Foundation’s Arecibo Observatory in Puerto Rico.
With these instruments, they will be able to see it’s true size, and even observe surface details as small as about 30 feet (10 meters).
Researchers have discovered most of the asteroids that are about a kilometers in size, but are now on the hunt for those that are about 140m – as they could cause catastrophic damage.
Although nobody knows when the next big impact will occur, scientists have found themselves under pressure to predict – and intercept – its arrival.
“Sooner or later we will get… a minor or major impact,” said Rolf Densing, who heads the European Space Operations Centre (ESOC) in Darmstadt, ahead of International Asteroid Day on Friday. “It may not happen in our lifetime, he said, but ‘the risk that Earth will get hit in a devastating event one day is very high.”
For now, there is little we can do. And yet, the first-ever mission to crash a probe into a small space rock to alter its trajectory suffered a major setback when European ministers declined in December to fund part of the project.
“We are not ready to defend ourselves’ against an Earth-bound object, said Densing. ‘We have no active planetary defense measures.”
Earlier this month, the space agency revealed an asteroid the size of a house set to narrowly skim the Earth in October, after it was spotted by scientists for the first time in five years.
The asteroid, dubbed 2012 TC4, first flitted past our planet in October 2012 at about double the distance of its next expected pass, before disappearing.
Now the European Space Agency (ESA) has tracked down the giant hunk of rock, which is about 15 to 30 metres (49 to 98 feet) long and roughly the size of a house.
TC4’s next approach, predicted for October 12, will bring the massive object “damn close”, according to experts, when it flies inside the moon’s orbit – just far out enough to miss our geostationary satellites.
Meanwhile, scientists say an Earth-like planet could be orbiting a star just 16 light years away from our own solar system – and, it could exist in the habitable zone.
In the nearby star system Gliese 832, scientists are so far aware of the existence of two exoplanets: a gas giant similar to Jupiter, and a rocky ‘super-Earth’ that sits very close to the host star.
Now, new calculations suggest there could be another world situated somewhere in between, with a mass between one and 15 times that of Earth.
In astronomy and astrobiology, the habitable zone is the range of orbits around a star in which a planet can support liquid water.
This habitable zone is also known as the ‘Goldilocks’ zone, taken from the children’s fairy tale.
The temperature from the star needs to be ‘just right’ so that liquid water can exist on the surface. The boundaries of the habitable zone are critical. If a planet is too close to its star, it will experience a runaway greenhouse gas effect, like Venus.
But if it’s too far, any water will freeze, as is seen on Mars. Since the concept was first presented in 1953, many stars have been shown to have a Goldilocks area, and some of them have one or several planets in this zone, like ‘Kepler-186f’, discovered in 2014.
“According to our calculations, this hypothetical alien world would probably have a mass between 1 to 15 Earth’s masses,” said the lead author Suman Satyal, a physics researcher, lecturer, and laboratory supervisory at the University of Texas at Arlington.
The researchers found that a planet less than 15 Earth masses could exist between .25 to 2.0 astronomical units from the red dwarf star at the center of the system.
To determine this, the team analyzed simulated data from Gliese 832 with an included Earth-mass planet. This revealed the different parameters by which such a planet could exist.
In one scenario, they even say it could sit within the star’s habitable zone.
“This is an important breakthrough demonstrating the possible existence of a potential new planet orbiting a star close to our own,” said UTA Physics Chair Alexander Weiss.
The team was also ‘able to demonstrate that the planet could maintain a stable orbit in the habitable zone of a red dwarf star for more than 1 billion years,’ Weiss says.
Scientists discovered the two known planets, Gliese 832b and Gliese 832c, through the radial velocity technique.
This detects the variations in the velocity of the star, as a result of the gravitational tug of unseen exoplanets circling it.
In the study, the team used these methods, along with others to simulate a possible third world in the system.
The analysis revealed several insights on a potential planet in this star system.
If it were located roughly 1 AU from the star, it could only be as large as 10 Earth masses, the researchers say, and would generate a radial velocity signal of 1.4 meters per second.
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