Newly Discovered Trans-Neptunian Comet Zooms By Earth in 3 Days

In only a few days, newly-discovered Comet Iwamoto will split the orbits of Earth and Mars, making a relatively close approach to our planet visible through small telescopes. This is a rare visit. The comet comes from the realm of Extreme Trans-Neptunian Objects, a distant region of the solar system inhabited by strange objects such as “Sedna” and “the Goblin.”

Animation below may take awhile to load:

Taken by michael jäger on February 7, 2019 @ Jauerling Austria

Discovered in Dec. 2018 by Japanese amateur astronomer Masayuki Iwamoto, using binoculars, this comet is a visitor from beyond the Kuiper Belt. It comes from the realm of Extreme Trans-Neptunian Objects (ETNOs) more than 5 times as far from the sun as Pluto. This means it could be a relative of other ETNOS such as Sedna, 2012 VP113 (“Biden“), and 2015 TG387 (“Goblin“).  More at

From NASA JPL, this image shows the position of the comet when it makes the closest approach to Earth on Feb 12th.

See the interactive orbit viewer here


Iwamoto will pass closest to Earth on February 12. This comet’s highly elliptical orbit around the Sun stretches beyond the Kuiper belt with an estimated 1,371 year orbital period. That should bring it back to the inner Solar System in 3390 AD. The comet is traveling very fast through space at a speed of 147,948 miles per hour (238,099 km/h) relative to Earth.

That’s a speed of 41 miles per second!

Above: Comet Iwamoto (C/2018 Y1), shows off a pretty, greenish coma at the upper left in this telescopic field of view. Taken on February 4 from the Mount John Observatory, University of Canterbury, the 30 minute long total exposure time shows the comet sweeping quickly across a background of stars and distant galaxies in the constellation Virgo. The long exposure and Iwamoto’s rapid motion relative to the stars and galaxies results in the noticeable blurred streak tracing the the comet’s bright inner coma. In fact, the streaked coma gives the comet a remarkably similar appearance to Messier 104 at lower right, popularly known as the Sombrero Galaxy. The comet, a visitor to the inner Solar System, is a mere 4 light-minutes away though, while majestic Messier 104, a spiral galaxy posing edge-on, is 30 million light-years distant.

Comet Iwamoto will be closest to Earth on February 12, 2019, at around 3:10 p.m. ET (20:10 UTC) It will safely pass by Earth at a distance of approximately 28 million miles (45 million km). With a brightness magnitude of +6.5, the comet will be visible only with the aid of optics, such as binoculars and telescopes.

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February 9, 2019 5:22 pm

Crikey! Don’t tell me that the planets have fallen to the LGBTIQ etc side…Trans-Nreptune? I had better lie down…

Tom Halla
February 9, 2019 5:27 pm

Damn! Not bright enough for naked eye.

Toby Nixon
February 9, 2019 5:35 pm

It’s not clear from the text or the drawing, but is the orbit of the comet in the same plane as Earth and Mars, or is it tilted?

Reply to  Toby Nixon
February 9, 2019 6:06 pm

slightly tilted, maybe 25* inclination. the dashed yellow lines dropping down from the comet’s orbit are perpendicular to earth’s orbital plane.

Steve Reddish
Reply to  Toby Nixon
February 9, 2019 6:24 pm

Looking carefully at the drawing, vertical white lines indicate the comet is “below” the plane of Earth’s orbit on the right side of the drawing. If the drawing is flipped from the norm so as to present the Earth as moving right to left, then the comet is currently north of the the plane of the Earth’s orbit. It appears to cross through that plane very close to the point of its closest approach to Earth.

John F. Hultquist
Reply to  Toby Nixon
February 9, 2019 7:15 pm

On the 2nd image above, I see a yellow line on the left with white/gray lines coming down. That yellow line appears to change color to white/gray as it passes through the solar system near Earth. Then those short whie/gray lines extend upward.

I do not see “dashed” yellow lines.
The 2 lines at the top and come togather at the Sun seem to be there for perspective. The verticle one is yellow at top, and changes color. I think the other is meant to cross the plane, should be a different color, and not change.

Those that work with such diagrams on a regular basis may have conventions a non-cosmic type is unaware of.

Toby Nixon
Reply to  Toby Nixon
February 9, 2019 10:35 pm

Thank you all. It’s clear now that you point it out! So that probably means it’s unlikely this comet would ever be a threat to Earth.

Sjoerd Schreuder
Reply to  Toby Nixon
February 10, 2019 2:02 pm

Note that the orbit of the planets and the comet is drawn in two shades: a brighter and a darker version of each color. This is the case in those diagrams.

The bright version is used for the part of the orbit above the solar plane, the darker version for the part below.

At the point of closest encounter, Earth is slightly below the plane (dark blue), while the comet is somewhat above it (bright white).

Javert Chip
February 9, 2019 5:36 pm

So some guy in Japan looks thru (hand-held?) binoculars, and finds something that can’t be seen by the naked eye AND NONE OF OUR COMET LOOK-OUT TECHNOLOGY SAW THIS COMING?

I had better lie down…

Rich Davis
Reply to  Javert Chip
February 9, 2019 6:01 pm

Oh don’t be such a worrywart. The world only has 11 years and 11 months left, so the odds of getting destroyed early by an ETNO are so low, it’s not worth considering.

Is Biden really an ETNO? I know he’s old like dirt.

Reply to  Javert Chip
February 10, 2019 8:35 am

There are a lot of amateur astronomers out there looking for comets and other things.

Doc Chuck
Reply to  MarkW
February 10, 2019 8:58 am

And most comets and many novae are discovered by amateur astronomers like myself, as the professionals are often sitting in an instrument monitoring room distant from the huge telescope and actually hardly ever look into a telescope eyepiece! So like this one, like the famous Shoemaker/Levy that broke up 25 years ago and plunged into Jupiter’s atmosphere leaving remnant marks for a while, is named for its amateur discoverers. And the heavy binoculars employed by Mr. Iwamoto are likely to have 4 inch or more objective lenses on a very sturdy mounting.

Doc Chuck
Reply to  Doc Chuck
February 11, 2019 11:58 am

And I might add that while large, high magnification telescope optics are great for later detailed imaging of such found newcomers, they have too narrow a field of view to be practical for the initial discovery stage.

February 9, 2019 5:36 pm

Previously unknown comets like this one are probably one of the most dangerous strike potentials to face humanity in the future. Since they are previously unknown, the lead time is relatively short for taking any kind of preventative measure (if we could). Also, the very high speed means the impact would be far more forceful and damaging than from a meteor of the same size. Thankfully, the odds of one of these unknown comets hitting the earth appear to be extremely small. But if one ever hits, it would be the ultimate in “climate change”.

D Matteson
Reply to  Bryan - oz4caster
February 9, 2019 8:57 pm

A comet striking the earth, reminds me of one of my favorite SF books, Lucifer’s Hammer by Larry Niven and Jerry Pournelle.

Reply to  D Matteson
February 10, 2019 5:58 am


Old Woman of the North
Reply to  Bryan - oz4caster
February 9, 2019 9:16 pm

One did once, millions of years ago, west of Alice Springs.
Called Goss’s Bluff it took geo scientists years to figure out what the formation is. Apparently the surface of the earth was 2km higher then. What remains is the impact site that far below. Very interesting to visit.

John Tillman
Reply to  Old Woman of the North
February 11, 2019 8:15 am

There have been lots of impacts.

Is early Cretaceous Gosse’s Bluff known to be from a comet rather than an asteroid?

The end Cretaceous impact on Yucatan was much bigger.

February 9, 2019 5:36 pm

Let’s see: Omuamua (which looked to me like the planet-killer Doomsday Weapon from Star Trek) passes through the solar system on a very unusual trajectory: in from deep space, close pass by the Sun, and then out again. Since then, it seems that several heretofore unknown comets have made/are making similar close passes to the Sun. “Rendezvous with Rama”, anyone?

Given our own abilities in remote sensing, wouldn’t it be more likely that any ET observers of use passive arrays and cameras to gather information on ourselves, rather than taking chances by actually coming down to the Earth’s surface?

Sure do wish we’d had something ready to do a close flyby of Ourmuamua when it zipped past… but maybe they knew that we didn’t.

Dr. Strangelove
Reply to  James Schrumpf
February 9, 2019 8:21 pm

Harvard astronomer and billionaire-physicist say Omuamua could be an alien spaceship!

Milner says. “We don’t want to be sensational in any way, and we are very realistic about the chances this is artificial”

Loeb says, “perhaps the aliens have a mothership that travels fast and releases baby spacecraft that freely fall into planetary system on a reconnaissance mission. In such a case, we might be able to intercept a communication signal between the different spacecraft.”

Reply to  Dr. Strangelove
February 10, 2019 8:38 am

If they were that advanced, wouldn’t they know enough to make sure that the Earth never came between the daughter and mother ships? Or at least maintain radio silence during those times?

Reply to  MarkW
February 11, 2019 9:23 am

Or not be using radio at all. Maybe they use Joe Haldeman’s “phased-neutrino communications” from “The Forever War.”

John Tillman
Reply to  James Schrumpf
February 11, 2019 9:59 am

This is actually an issue for SETI. It’s possible, indeed likely, that broadcast EM radiation is a brief phase in the history of communication of any advanced civilization. After only about a century, we Earthlings are moving beyond it.

February 9, 2019 5:39 pm

Interesting, but I can’t find any link which estimates the size of this comet. If it was headed for earth and was only discovered in Dec. 2018 it wouldn’t give us much time to get ready for a collision…

Reply to  Jon P Peterson
February 9, 2019 5:58 pm

This was in 2012, only 7 years ago a comet hit Jupiter:

Reply to  Jon P Peterson
February 9, 2019 6:14 pm

Sorry according to wackapedia it was 1994 – 25 years ago. Seems like only yesterday…

Reply to  Jon P Peterson
February 10, 2019 6:37 am

“Jupiter is 2.5 times more massive than all the rest of the planets in the Solar System combined”
Because of its mass Jupiter absorbs the objects that might otherwise have ended our little operation here on earth.
Enjoying your continued existence? Thank Jupiter.

February 9, 2019 5:45 pm

Man, this is cool! (My inner-10-year-old speaking. 🙂 )

James Bull
Reply to  PaulH
February 10, 2019 3:54 am

Love that idea and will take and use endlessly from now on.

James Bull

February 9, 2019 5:56 pm

The inclination of the orbit is 160°. This means it’s retrograde and therefore circles the sun in the opposite direction to the planets.

So in that NASA screenshot it’s travelling left to right while the Earth travels right to left. Hence the very high approach speed quoted. This translates to 66km/sec which is comparable to the fastest meteor showers (circa 72km/sec).

Its 160° inclination means it’s actually inclined 20° from the ecliptic plane. The reason they don’t say 20° is that 20° is reserved for bodies going the same way round the sun as the planets. Since it’s measured from the ascending node (crossing the ecliptic from south to north) you have to measure right round, through 90° and on to 160° in order to get a 20° inclination going the opposite way hence 160° inclination. If 180°, it would be orbiting in the ecliptic plane but in the opposite (retrograde) direction. And its approach speed would be a little bit more, close to the maximum of a little above 72km/sec.

The 66km/sec approach velocity would indeed be much more catastrophic for us than an average asteroid because they do circa 28-38 km per sec in their actual orbital speed at 1AU which translates to between 1 and 36 km/sec depending if they’re sailing along next to us and then drifting across our line (1km/sec) or highly inclined/eccentric with a high aphelion (36km/sec). AFAIK there are no retrograde NEOs hence the geocentric approach speeds (can’t be much more than 36km/sec although I saw one comet-like asteroid with 38km/sec approach speed out of 1000’s I’ve monitored. Most approach Earth between 5 and 20 km/sec, maybe 80-90%.

Geocentric approach velocity is what we see as opposed to its orbital velocity because we’te travelling at 30km/sec as well so you have to strip that 30km/sec out as if the Earth is stationary and watch the resultant (vector summed) approach speed and angle of approach (known as the geocentric radial velocity vector).

Reply to  Scute
February 9, 2019 6:01 pm


“So in that NASA screenshot it’s travelling left to right while the Earth travels right to left”

It’s the opposite. I got right & left wrong way round.

I find it difficult to scroll the comment box up & down and insert the cursor so I don’t proofread it. It’s not impossible but really tricky.

John F. Hultquist
Reply to  Scute
February 9, 2019 7:20 pm

Despite that, thanks. John

February 9, 2019 7:56 pm

It’s begun …

Russian islands declare state of emergency over polar bear ‘invasion’

Posted about 3 hours ago

A remote Russian region has declared a state of emergency over the ‘invasion’ of dozens of polar bears in its human settlements. Authorities in the Novaya Zemlya islands, home to a few thousand people, say there are cases of bears attacking people and entering residential and public buildings and in a statement have appealed for help to tackle “a mass invasion of polar bears into inhabited areas”

Reply to  WXcycles
February 9, 2019 8:11 pm

Trap the polar bears (humanely of course) and deliver them to the hallowed halls of the UN, specifically the floor housing the IPCC offices. Just the sort of reality check up show that computer modelling might have practical limitations.

John F. Hultquist
Reply to  WXcycles
February 9, 2019 9:58 pm

How can this be? Big Al said Polley Bears were all dying.

Reply to  John F. Hultquist
February 9, 2019 11:21 pm

He cloned them … they have laser beams …

Reply to  John F. Hultquist
February 11, 2019 5:56 pm

So today I hear that the masses of (presumably nearly extinct) hungry polar bears invading Russia are doing so because of melting sea ice (forget for the moment that the polar ice is increasing, just play along) and decreased food supply. What’s the matter with Canada? Aren’t we hospitable?

February 9, 2019 8:48 pm

Comet C/2018 Y1 (Iwamoto) Ephemeris
The following table lists the ephemerides of Comet C/2018 Y1 (Iwamoto) computed for the past and next 7 days, with a 24 hours interval. Click on each row of the table to locate Comet C/2018 Y1 (Iwamoto) in our Online Planetarium at the chosen date.

Date Right Ascension Declination Magnitude Constellation
2019 Feb 03 12h 48m 16s -10° 45’ 05” 11.70 Virgo
2019 Feb 04 12h 38m 30s -09° 06’ 15” 11.56 Virgo
2019 Feb 05 12h 27m 29s -07° 12’ 33” 11.42 Virgo
2019 Feb 06 12h 14m 58s -05° 01’ 50” 11.28 Virgo
2019 Feb 07 12h 00m 51s -02° 32’ 04” 11.15 Virgo
2019 Feb 08 11h 44m 54s +00° 18’ 03” 11.02 Virgo
2019 Feb 09 11h 26m 58s +03° 28’ 53” 10.91 Leo
2019 Feb 10 11h 06m 57s +06° 58’ 31” 10.81 Leo
2019 Feb 11 10h 44m 53s +10° 42’ 20” 10.74 Leo
2019 Feb 12 10h 20m 53s +14° 32’ 35” 10.70 Leo
2019 Feb 13 09h 55m 23s +18° 19’ 05” 10.69 Leo
2019 Feb 14 09h 28m 54s +21° 51’ 03” 10.72 Leo
2019 Feb 15 09h 02m 12s +24° 59’ 26” 10.78 Cancer
2019 Feb 16 08h 35m 58s +27° 38’ 40” 10.88 Cancer

Copied from an online site. Not sure which one at this point. Corrections welcome.


February 9, 2019 8:53 pm
Jean Meeus
February 9, 2019 11:06 pm

Firstly, comet Iwamoto (designation C/2018 Y1) reached perihelion on 2019 Feb 7, at a distance of 1.29 astronomical units from the Sun, well outside the orbit of the Earth.
Secondly, it’s not the first time that we observe comets on nearly parabolic orbits. So what is the news?

Paul Penrose
Reply to  Jean Meeus
February 10, 2019 1:53 pm

Ones that come from that far out are rare. Rare == news.

Reply to  Jean Meeus
February 11, 2019 1:01 am

Um, they’re cool?

Non Nomen
February 9, 2019 11:35 pm

Live and learn. Thanks!

February 10, 2019 4:33 am

Now tis comet is serous business. Forget all the rubbish about the world overheating by a mere .5C, this s real danger.

So all the money that has been spent, and still is, , could have made NASA turn from Earth studies, to seriously thinking about both detecting and then deflecting such comets in the future.

MJE iiii

February 10, 2019 5:02 am

I’m curious if this is connected to the wandering poles. Maybe the cause of it?

Reply to  Anthony Watts
February 10, 2019 9:21 am

Explain why that isn’t a valid question.

Tom Abbott
Reply to  Ralph Tucker
February 10, 2019 10:00 am

Explain how the wandering north pole of the Earth is connected to a wandering comet. There is no obvious connection, which is why your question was questioned.

Reply to  Tom Abbott
February 11, 2019 7:12 am

It might in the future, not the past or the present, but only if the comet is very, very large and scores a direct hit, but at the time of this statement neither of two conditions that have to be satisfied to cause such effect, is true.

Reply to  vukcevic
February 11, 2019 8:23 am

I like that, no obvious connection and It might in the future, not the past or the present. Both statements suggest possibilities my question is valid. There is also research about attraction between certain bodies being greater due to unforeseen circumstances. Maybe the comet and Earth have had prior experiences that cause this connection.

John W Braue
Reply to  Ralph Tucker
February 10, 2019 6:20 pm

The heck with the wandering poles, what about the Wandering Jew?

February 11, 2019 7:06 am

Pesky ex-heliospherics, you are invading our space, keep out, we have enough problems with our own terrestrially grown Greenies.

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