Watch Asteroid 3122 Florence Zip Past Earth This Weekend

NEO asteroid
NEO asteroid
An artist’s conception of an NEO asteroid similar to 3122 Florence orbiting the Sun. Credit: NASA/JPL.

Ready to hunt for low-flying space rocks? We’ve got an interesting pass of a Near Earth Asteroid (NEA) this upcoming U.S. Labor Day weekend, one that just slides over the +10th magnitude line into binocular range.

We’re talking about asteroid 3122 Florence, which passes 4.4 million miles from our fair planet (that’s 7 million kilometers, about 18 times the distance from Earth to the Moon) this Friday on September 1st at 12:06 Universal Time (UT)/ 8:06 AM Eastern Daylight Saving Time (EDT).

Universe Today ran an article on the close pass about a week ago. Now, we’d like to show you how to see this asteroid as it glides by.

Ordinarily, a four million mile pass (about 4.7% of an astronomical unit, just under the criterion to make 3122 Florence a Near Earth Object) isn’t enough to grab our attention. Lots of asteroids pass closer weekly, and 3122 Florence is certainly no danger to the Earth this or any week in the near future. What makes this asteroid an attractive target is its size: NASA’s NEOWISE and Spitzer infrared telescope missions estimate that 3122 Florence is about 2.7 miles (4.4 kilometers) in diameter, a pretty good-sized chunk of rock as near Earth asteroids go.

Florence orbit
The inclined orbit of 3122 Florence. Credit: NASA/JPL.

The last large asteroid with a similar close approach was 4179 Toutatis, which passed just under four lunar distances (a little under a million miles) from the Earth on September 29th, 2004.

Asteroid 3122 Florence (1981 ET3) was discovered by prolific asteroid hunter Schelte J. Bus from Siding Spring observatory in Australia on the night of March 2nd, 1981. Named after social reformer and founder of modern nursing Florence Nightingale, this weekend’s pass is the closest 3122 Florence gets to Earth over a 600 year plus span, running from 1890 (well before its discovery) out past 2500 AD.

Plans are afoot to ping 3122 Florence using Goldstone and Arecibo radars as it passes by the weekend. we might just see if it has a any attending moonlets or a strange bifurcated shape like comets 67/P Churyumov-Gerasimenko or Comet 45/P Honda-Mrkos-Pajdušáková very soon.

2014 JO25
Asteroid 2014 JO25 imaged by Arecibo earlier this year… are contact binary ‘rubber-duck’ shaped asteroids and comets a thing? Credit: NASA/Arecibo/NSF.

3122 Florence has an inclined orbit, tilted 22 degrees in respect to the ecliptic plane. Orbiting the Sun once every 859 days, 3122 Florence travels from around 1 to 2.5 AUs from the Sun, making it an Amor class asteroid which journeys beyond the orbit of Mars and approaches but doesn’t pass interior to the orbit of the Earth.

This week’s pass sees 3122 Florence rapidly vaulting up from the southern to northern hemisphere.

This apparition culminates on Friday, September 1st, at 12:06 UT as the asteroid crosses the along the border of the constellations Equuleus and Delphinus at closest approach, reaching +9th magnitude. 3122 Florence will be moving at 20′ per hour (that’s about 2/3rds the diameter of the Full Moon) at closest approach, fast enough that you’ll notice its motion against the background stars in a low power field of view after about 10 minutes or so.

Path of Florence
The path of 3122 Florence through the sky this week, times for the tick marks are in EDT (UT-4 hours). Credit: Starry Night Education software.

3122 Florence crosses through the constellations Piscis Austrinus, Capricornus, Aquarius, Equuleus and Delphinus this week. Keep in mind, the Moon is headed towards Full next week on September 6th, making the next few evenings a good time to track this fleeting space rock down.

3122 Florence from August 28th, about 8 million kilometers from the Earth. The asteroid is the center dot, while the streak to the left is the geostationary satellite AMC-14. Credit: the Virtual Telescope Project.

Finding 3122 Florence

3122 Florence races across the ecliptic northward on the night of August 29th and also crosses the celestial equator on September 1st

Tonight is also a good time to track down 3122 Florence, as it passes just 16′ from +3.8 magnitude star Zeta Capricorni. It also threads its way through the tiny the diamond-shaped asterism of Delphinus the Dolphin just over week after its closest pass on the evening of Saturday, September 9th.

Currently, 3122 Florence is 45 degrees above the southern horizon around local midnight for observers based along 30 degrees north latitude. The best view during Friday’s pass is from the Pacific Rim, including Australia, New Zealand and surrounding regions at closest approach.

Earth view
The orientation of the Earth as seen from asteroid 3122 Florence during Friday’s closest approach. Credit: Starry Night Education software.

North American viewers will get a good view at local midnight just about eight hours prior to closest approach on the night of August 31st/September 1st, about 60 degrees above the southern horizon. The next good views occur the following evening about 16 hours after closest approach, as the asteroid is receding but 10 degrees higher above the southern horizon.

The 24 hour celestial path of of 3122 Florence through the night sky, centered on the September 1st closest approach. Tick mark times are in EDT (UT-4 hours). Created using Starry Night Education software.

A series short wide field exposures over about an hour revealing stars down to +10 magnitude should reveal the motion of 3122 Florence against the starry background. A good visual alternative is to sketch the suspect star field about 10 minutes apart, carefully looking for a ‘star’ that has moved during the intervening time.

JPL Horizons is a good place to generate accurate right ascension and declination coordinates for 3122 Florence to aid you in your quest. This one is distant enough to simple geocentric coordinates should suffice, and observer parallax shouldn’t shift the position of the asteroid significantly.

Clouded out? The good folks over at the Virtual Telescope Project will be featuring 3122 Florence during a live webcast starting on Thursday, August 31st at 19:30 UT/3:30 PM EDT.

We can be thankful that 3122 Florence isn’t headed Earthward, as it’s perhaps about half the size of the 10-15 kilometer diameter Chicxulub impactor that hit the Yucatan 65 million years ago, causing a very bad day for the dinosaurs. Plus, it would just be weird if an asteroid named after humanitarian Florence Nightingale caused the extinction of humanity…

And this is a great pre-show for a smaller and closer anticipated asteroid pass coming up in a few short weeks, as 2012 TC4 buzzes the Earth on October 12th, 2017.

Good luck in your quest to find 3122 Florence… let us know what you see!

Dinosaur Killing Asteroid Hit in Exactly the Wrong Place

When an asteroid struck the Yucatan region about 66 million years ago, it wiped out the dinosaurs, and most of life on Earth. If it had hit elsewhere, the dinosaurs might well have survived. Credit: NASA/Don Davis

The asteroid that struck Earth about 66 million years ago and led to the mass extinction of dinosaurs may have hit one of the worst places possible as far as life on Earth was concerned. When it struck, the resulting cataclysm choked the atmosphere with sulphur, which blocked out the Sun. Without the Sun, the food chain collapsed, and it was bye-bye dinosaurs, and bye-bye most of the other life on Earth, too.

But, as it turns out, if it had struck a few moments earlier or later, it would not have hit the Yucatan, and things may have turned out differently. Why? Because of the concentration of the mineral gypsum in that area.

The place where the asteroid hit Earth is called the Chicxulub Crater, and scientists have been studying that area to try to learn more about the impact event that altered the course of life on Earth. An upcoming BBC documentary called “The Day The Dinosaurs Died,” focuses on what happened when the asteroid struck. Drill-core samples from the Yucatan area help explain the events that followed the impact.

The drilling rig off the coast of the Yucatan. The rig was there in the Spring of 2016 obtaining samples from the seafloor. Image: BBC/Barcroft Productions.
The drilling rig off the coast of the Yucatan. The rig was there in the Spring of 2016 obtaining samples from the seafloor. Image: BBC/Barcroft Productions.

The core samples, which are from as deep as 1300 m beneath the Gulf of Mexico, are from a feature called the peak ring.

When the asteroid struck Earth, it excavated a crater 100 km across and 30 km deep. This crater collapsed into a wider but shallower crater 200 km across and a few km deep. Then the center of the crater rebounded, and collapsed again, leaving the peak ring feature. The Chicxulub crater is now partly under water, and that’s where a drilling rig was set up to take samples.

The peak ring is at the center of the crater, offshore of the Yucatan Peninsula. Image: NASA/BBC
The peak ring is at the center of the crater, offshore of the Yucatan Peninsula. Image: NASA/BBC

The core samples revealed rock that has been heavily fractured and altered by immense pressures. The same impact that altered those rocks would have generated an enormous amount of heat, and that heat created an enormous cloud of sulphur from the vaporized gypsum. That cloud persisted, which led to a global winter. Temperatures dropped, plant growth came to a standstill, and the course of events on Earth were altered forever.

“Had the asteroid struck a few moments earlier or later, rather than hitting shallow coastal waters it might have hit deep ocean,” documentary co-presenter Ben Garrod told the BBC.

“This is where we get to the great irony of the story – because in the end it wasn’t the size of the asteroid, the scale of blast, or even its global reach that made dinosaurs extinct – it was where the impact happened,” said Ben Garrod, who presents “The Day The Dinosaurs Died” with Alice Roberts.

“An impact in the nearby Atlantic or Pacific oceans would have meant much less vaporised rock – including the deadly gypsum. The cloud would have been less dense and sunlight could still have reached the planet’s surface, meaning what happened next might have been avoided,” said Garrod.

In the documentary, host Alice Roberts will also visit a quarry in New Jersey, where fossil evidence shows a massive die-off in a very short period of time. In fact, these creatures could have died on the very day that the asteroid struck.

The core samples from the drilling rig show rocks that were subjected to immense heat and pressure at the time of the impact. Image: Barcroft Productions/BBC
The core samples from the drilling rig show rocks that were subjected to immense heat and pressure at the time of the impact. Image: Barcroft Productions/BBC

“All these fossils occur in a layer no more than 10cm thick,” palaeontologist Ken Lacovara tells Alice. “They died suddenly and were buried quickly. It tells us this is a moment in geological time. That’s days, weeks, maybe months. But this is not thousands of years; it’s not hundreds of thousands of years. This is essentially an instantaneous event.”

There’s lots of evidence showing that an asteroid struck Earth about 66 million years ago, causing widespread extinction. NASA satellite images clearly show crater features, now obscured by 66 million years of geological activity, but still visible.

There’s also what’s called the K-T Boundary, or Cretaceous-Tertiary Boundary. It’s a geological signature dating to 66 million years ago, which marks the end of the Cretaceous Period. In that boundary is a layer of iridium at very high concentrations, much higher than is normally present in the Earth’s crust. Since iridium is much more abundant in asteroids, the conclusion is that it was probably deposited by an asteroid.

But this is the first evidence that shows how critical the actual location of the event may have been. If it had not struck where it had, dinosaurs may never have gone extinct, you and I would not be here, and things on Earth could look much different.

It might sound like the stuff of science fiction, but who knows? Maybe a race of intelligent lizards might already have mastered interstellar travel.