JPL: Newly Discovered Comet Is Likely Interstellar Visitor

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JPL: Newly Discovered Comet Is Likely Interstellar Visitor

Post by bystander » Fri Sep 13, 2019 7:56 pm

Newly Discovered Comet Is Likely Interstellar Visitor
NASA | JPL-Caltech | 2019 Sep 13
A newly discovered comet has excited the astronomical community this week because it appears to have originated from outside the solar system. The object - designated C/2019 Q4 (Borisov) - was discovered on Aug. 30, 2019, by Gennady Borisov at the MARGO observatory in Nauchnij, Crimea. The official confirmation that comet C/2019 Q4 is an interstellar comet has not yet been made, but if it is interstellar, it would be only the second such object detected. The first, 'Oumuamua, was observed and confirmed in October 2017.

The new comet, C/2019 Q4, is still inbound toward the Sun, but it will remain farther than the orbit of Mars and will approach no closer to Earth than about 190 million miles (300 million kilometers).

After the initial detections of the comet, Scout system, which is located at NASA's Jet Propulsion Laboratory in Pasadena, California, automatically flagged the object as possibly being interstellar. ...
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Gemini Captures Multicolor Image of First Interstellar Comet

Post by bystander » Fri Sep 13, 2019 8:43 pm

Gemini Observatory Captures Multicolor Image of First Interstellar Comet
Gemini Observatory | 2019 Sep 13
The first-ever comet from beyond our Solar System has been successfully imaged by the Gemini Observatory in multiple colors. The image of the newly discovered object, denoted C/2019 Q4 (Borisov), was obtained on the night of 9-10 September using the Gemini Multi-Object Spectrograph (GMOS) on the Gemini North Telescope on Hawaii’s Maunakea.

“This image was possible because of Gemini’s ability to rapidly adjust observations and observe objects like this, which have very short windows of visibility,” said Andrew Stephens of Gemini Observatory who coordinated the observations. “However, we really had to scramble for this one since we got the final details at 3:00 am and were observing it by 4:45!”

The image shows a very pronounced tail, indicative of outgassing, which is what defines a cometary object. This is the first time an interstellar visitor to our Solar System has clearly shown a tail due to outgassing. The only other interstellar visitor studied in our Solar System was ‘Oumuamua which was a very elongated asteroid-like object with no obvious outgassing.

The Gemini observations used for this image were obtained in two color bands (filters) and combined to produce a color image. The observations were obtained as part of a target of opportunity program led by Piotr Guzik and Michal Drahus at the Jagiellonian University in Krakow (Poland). ...

Interstellar Comet 2I/Borisov ~ Piotr Guzik et al
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IAU: Naming of New Interstellar Visitor, 2I/Borisov

Post by bystander » Wed Sep 25, 2019 10:46 pm

Naming of New Interstellar Visitor, 2I/Borisov
International Astronomical Union | 2019 Sep 24

Second interstellar object has been spotted and named just two years after the first

A new object from interstellar space has been found within the Solar System, only the second such discovery of its kind. Astronomers are turning their telescopes towards the visitor, which offers a tantalising glimpse beyond our Solar System and raises some puzzling questions. The object has been given the name 2I/Borisov by the IAU.

On 30 August 2019 the amateur astronomer Gennady Borisov, from MARGO observatory, Crimea, discovered an object with a comet-like appearance. The object has a condensed coma, and more recently a short tail has been observed. Mr. Borisov made this discovery with a 0.65-metre telescope he built himself.

After a week of observations by amateur and professional astronomers all over the world, the IAU Minor Planet Center was able to compute a preliminary orbit, which suggested this object was interstellar — only the second such object known to have passed through the Solar System.

The orbit is now sufficiently well known, and the object is unambiguously interstellar in origin; it has received its final designation as the second interstellar object, 2I. In this case, the IAU has decided to follow the tradition of naming cometary objects after their discoverers, so the object has been named 2I/Borisov. ...
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Yale: Get Ready for More Interstellar Objects

Post by bystander » Thu Sep 26, 2019 9:11 pm

Get Ready for More Interstellar Objects
Yale University | 2019 Sep 26
Gregory Laughlin and Malena Rice weren’t exactly surprised a few weeks ago when they learned that a second interstellar object had made its way into our solar system.

The Yale University astronomers had just put the finishing touches on a new study suggesting that these strange, icy visitors from other planets are going to keep right on coming. We can expect a few large objects showing up every year, they say; smaller objects entering the solar system could reach into the hundreds each year. ...

“There should be a lot of this material floating around,” said Rice, a graduate student at Yale and first author of the study. “So much more data will be coming out soon, thanks to new telescopes coming online. We won’t have to speculate.” ...

Of course, for scientists one of the big questions arising from the appearance of interstellar objects is: “Where did they come from?” An easy answer would be that they are ejected planetary building blocks -- planetesimals -- from other solar systems. But upon first look, there’s a problem with that theory, say researchers: A close study of the roughly 4,000 confirmed planets outside of our solar system shows that most of them are located too close to their parent stars to readily eject a planetesimal. Planetesimals stirred up by most currently known planets would remain stuck in orbits in the systems where they formed. ...

Hidden Planets: Implications from 'Oumuamua and DSHARP ~ Malena Rice, Gregory Laughlin
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Re: JPL: Newly Discovered Comet Is Likely Interstellar Visitor

Post by MarkBour » Fri Sep 27, 2019 2:11 am

I can't wait to hear more data on this. Larger than Oumuamua, and likely to be around a lot longer for view. Now don't tell me it came from a direction at all close to the origin direction of Oumuamua. That would be very spooky.
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Re: JPL: Newly Discovered Comet Is Likely Interstellar Visitor

Post by BDanielMayfield » Sat Sep 28, 2019 2:36 pm

MarkBour wrote:
Fri Sep 27, 2019 2:11 am
I can't wait to hear more data on this. Larger than Oumuamua, and likely to be around a lot longer for view. Now don't tell me it came from a direction at all close to the origin direction of Oumuamua. That would be very spooky.
No, they came in from differing directions. I2/Borisov's home system is thought to be Kruger 60.
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ING: Gas Molecules Detected in Comet from Another Star

Post by bystander » Tue Oct 01, 2019 4:29 pm

Astronomers Detect Gas Molecules in Comet from Another Star
Isaac Newton Group of Telescopes | 2019 Sep 30
An international team of astronomers have made a historic discovery using the William Herschel Telescope (WHT), detecting gas molecules in a comet which has tumbled into our Solar System from another star. It is the first time that astronomers have been able to detect this type of material in an interstellar object.

The discovery marks an important step forward for science as it will now allow scientists to begin deciphering exactly what these objects are made of and how our home Solar System compares with others in our galaxy. ...

Comet Borisov was discovered by Crimean amateur astronomer Gennadiy Borisov in August. Observations over the following 12 days showed that it was not orbiting the Sun, but was just passing through the Solar system on its own path through our galaxy.

By 24 September it had been renamed 2I/Borisov, the second interstellar object ever discovered in our Solar System by astronomers. Unlike the first such object discovered two years ago, 1I/'Oumuamua, this object appeared as a faint comet, with a surrounding atmosphere of dust particles, and a short tail. ...

Detection of CN gas in Interstellar Object 2I/Borisov ~ Alan Fitzsimmons et al Interstellar Comet C/2019 Q4 (Borisov) ~ Piotr Guzik et al
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WHTF: Interstellar Interloper CN!

Post by neufer » Tue Oct 01, 2019 5:34 pm

https://www.etymonline.com/search?q=interloper wrote:
Interloper (n.) 1590s, enterloper, "unauthorized trader trespassing on privileges of chartered companies," probably a hybrid from inter- "between" + -loper (from landloper "vagabond, adventurer," also, according to Johnson, "a term of reproach used by seamen of those who pass their lives on shore"); perhaps from a dialectal form of leap, or from Middle Dutch loper "runner, rover," from lopen "to run," from Proto-Germanic *hlaupanan "to leap". OED says Dutch enterlooper "a coasting vessel; a smuggler" is later than the English word and said by Dutch sources to be from English. General sense of "self-interested intruder" is from 1630s.
https://en.wikipedia.org/wiki/2I/Borisov wrote:
<<2I/Borisov is the first observed interstellar comet and second observed interstellar interloper, after ʻOumuamua. 2I/Borisov has a heliocentric orbital eccentricity of 3.3 and is not bound to the Sun. The comet will pass through the ecliptic of the Solar System in December 2019, with the closest approach to the Sun at just under 2 au on 8 December 2019. The comet was discovered on 30 August 2019 by amateur astronomer Gennadiy Borisov at his personal observatory MARGO using a 0.65-meter telescope he designed and built himself. The discovery of 2I/Borisov by Borisov has been compared to the discovery of Pluto by Clyde Tombaugh.

Unlike ʻOumuamua which had an asteroidal appearance, Borisov's initial observations and subsequent third-party validation affirmed the presence of a coma around the body, indicating a cloud of dust and gas that would classify the body as a comet. Initial estimates for the size of 2I/Borisov's nucleus, published on 12 September 2019, ranged from 2 to 16 km, based on observations made by Karen Meech at the University of Hawaii. An improved size estimate, based on the production rate of certain molecules in the comet's coma, was published by Alan Fitzsimmons, Karen Meech and others on 26 September. They estimated that the nucleus is between 1.4 and 6.6 km in diameter. On 13 September 2019, the Gran Telescopio Canarias obtained a preliminary (low-resolution) visible spectrum of 2I/Borisov that revealed that this object has a surface composition not very different from that found in typical Oort Cloud comets. Also, the William Herschel Telescope [WHT] located at the island of La Palma, reported the detection of cyanide (formula: CN) emission at 388 nm (this type of emission has been detected in many other comets, including comet Halley) and put constraints on the production rate of other molecules like diatomic carbon (formula C2).

2I/Borisov's trajectory is extremely hyperbolic, having an orbital eccentricity of 3.3 to 3.4. This is much higher than the 300+ known weakly hyperbolic comets, with heliocentric eccentricities just over 1.0, and even ʻOumuamua with an eccentricity of 1.2. 2I/Borisov also has a hyperbolic excess velocity of 32 km/s (6.77 au/yr), much higher than what could be explained by perturbations, which could produce velocities when approaching an infinite distance from the Sun of less than a few km/s. These two parameters are important indicators of 2I/Borisov's interstellar origin. For comparison, the Voyager 1 spacecraft, which is leaving the Solar System, is traveling at 16.9 km/s (3.57 au/yr). 2I/Borisov has a much larger eccentricity than ʻOumuamua due to its higher excess velocity and its significantly higher perihelion distance. At this larger distance, the Sun's gravity is less able to alter its path as it passes through the Solar System.

2I/Borisov entered the Solar System from the direction of Cassiopeia near the border with Perseus and very close to the galactic plane. From September until mid-November the comet is in the northern sky and will cross the celestial equator on 13 November 2019 entering the southern sky. Due to the 44 degree orbital inclination, 2I/Borisov does not make any notable close approaches to the planets. On 6 December 2019, the comet will be an equal distance of 2 au from the Sun and Earth. On 8 December 2019, the comet will come to perihelion (closest approach to the Sun) and will be near the edge of the inner asteroid belt. In late December, it will be about 1.9 au from Earth and have a solar elongation of about 80°. It will leave the Solar System in the direction of Telescopium.

2I/Borisov's velocity (32 km/s relative to the Sun) and the direction from which it entered the Solar System indicates that it originates from the galactic disk of the Milky Way, rather than from the galactic halo. One theoretical possibility is that 2I/Borisov had passed within 1.7 pc of the star Kruger 60 [radial velocity = –33.1/–31.9 km/s] at a low velocity of 3.4 km/s around a million years ago. In interstellar space, 2I/Borisov takes roughly 9000 years to travel a light-year relative to the Sun.

Observations using the Hubble Space Telescope are planned to begin on October 8, when the comet moves far enough from the Sun to be safely observed by the telescope. Hubble is less affected by the confounding effects of the coma than ground-based telescopes, which will allow it to study the rotational light curve of 2I/Borisov's nucleus. This should facilitate an estimate of its size and shape. The observations will serve as a baseline for possible further observations, as the comet approaches perihelion and then leaves the Solar System. In the event that the nucleus disintegrates, as is sometimes seen with small comets, Hubble can be used to study the evolution of the disintegration process.

The higher hyperbolic excess velocity of 2I/Borisov of 32 km/s makes it even harder to reach for a spacecraft than 1I/'Oumuamua (26 km/s). According to a team of the Initiative for Interstellar Studies, a two-ton spacecraft could theoretically have been sent in July 2018 to intercept 2I/Borisov using a Falcon Heavy-class launcher, but only if the object had been discovered much earlier than it was. Launches after the actual discovery date would require a significantly larger launcher such as the Space Launch System (SLS) and Oberth manoeuvres near Jupiter and near the Sun. By September 2019, even an SLS-class launcher would only be able to deliver a 3 kg (6.6 lb) payload (such as a CubeSat) into a trajectory that could intercept 2I/Borisov in 2045 at a relative speed of 34 km/s. According to congressional testimony, NASA may need at least five years of preparation to launch such an intercepting mission.>>
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Re: JPL: Newly Discovered Comet Is Likely Interstellar Visitor

Post by BDanielMayfield » Tue Oct 01, 2019 9:00 pm

It’s extra smooth, hyperbolic trajectory has been brought to us by Kruger Interstellar Smoothing.
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Jagiellonian: Interstellar Comet with a Familiar Look

Post by bystander » Tue Oct 15, 2019 4:34 pm

Interstellar Comet with a Familiar Look
Jagiellonian University, Krakow | 2019 Oct 14
A new comet discovered by amateur astronomer Gennady Borisov is an outcast from another star system, yet its properties determined so far are surprisingly familiar ...

For decades, astronomers have speculated that the space between stars may be populated by exosolar minor bodies – comets and asteroids – ejected from their home planetary systems. Studies have also suggested that these bodies may occasionally pass through the Solar System and be identified thanks to their strongly open orbits. The discovery of ‘Oumuamua two years ago brought the long-awaited confirmation, sparking hopes for subsequent detections.

A team of scientists led by astronomers from the Jagiellonian University in Kraków had done their homework well ahead of time. Prompted by the earlier visit of ‘Oumuamua, they created a computer programme nicknamed ‘Interstellar Crusher’ that scanned tirelessly through online data of newly-found comets and asteroids in search of guests from far away. On 8 September 2019 at 04:15 universal time, the programme issued a red alert and notified the team of a possible new hyperbolic object arriving from interstellar space. ... The body had been first spotted by Gennady Borisov a week earlier, although its identity had been unknown at that time. A closer investigation into the object’s orbit confirmed its exosolar origin, making it the second-known interstellar interloper. ...

Initial Characterization of Interstellar Comet 2I/Borisov ~ Piotr Guzik et al
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Hubble Observes New Interstellar Visitor (Comet 2I/Borisov)

Post by bystander » Wed Oct 16, 2019 4:48 pm

Hubble Observes New Interstellar Visitor
ESA Hubble Photo Release | 2019 Oct 16
On 12 October 2019, the NASA/ESA Hubble Space Telescope provided astronomers with their best look yet at an interstellar visitor — Comet 2I/Borisov — which is believed to have arrived here from another planetary system elsewhere in our galaxy.

This observation is the sharpest view ever of the interstellar comet. Hubble reveals a central concentration of dust around the solid icy nucleus.

Comet 2I/Borisov is only the second such interstellar object known to have passed through our Solar System. In 2017, the first identified interstellar visitor, an object dubbed ‘Oumuamua, swung within 38 million kilometres of the Sun before racing out of the Solar System. ...

As the second interstellar object found to enter our Solar System, the comet provides various invaluable insights. For example, it offers clues to the chemical composition, structure, and dust characteristics of a planetary building block presumably forged in an alien star system a long time ago and far away. ...

Hubble photographed the comet at a distance of approximately 420 million kilometres from Earth [1]. The comet is travelling toward the Sun and will make its closest approach to the Sun on 7 December, when it will be twice as far from the Sun as Earth. It is also following a hyperbolic path around the Sun, and is currently blazing along at the extraordinary velocity of over 150 000 kilometres per hour. By the middle of 2020, the comet will be on its way back into interstellar space where it will drift for millions of years before maybe one day approaching another star system. ...

Hubble Observes First Confirmed Interstellar Comet
NASA | GSFC | STScI | HubbleSite | 2019 Oct 16
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Re: JPL: Newly Discovered Comet Is Likely Interstellar Visitor

Post by BDanielMayfield » Sat Nov 09, 2019 6:13 pm

This paragraph which Art quoted from the wikipedia article on 2I/Borisov in another topic caught my attention:
As seen from Earth, the comet is in the northern sky from September until mid-November. It will cross the celestial equator on 13 November 2019 entering the southern sky. On 6 December 2019, the comet will be an equal distance of 2 au from the Sun and Earth.[5] On 8 December 2019, the comet will come to perihelion (closest approach to the Sun)[3] and will be near the edge of the inner asteroid belt.[e] In late December, it will be about 1.9 au from Earth and have a solar elongation of about 80°.[5] Due to its 44° orbital inclination, 2I/Borisov does not make any notable close approaches to the planets.[3] 2I/Borisov entered the Solar System from the direction of Cassiopeia near the border with Perseus. This direction indicates that it originates from the galactic plane, rather than from the galactic halo.[30] In interstellar space, 2I/Borisov takes roughly 9000 years to travel a light-year relative to the Sun.[f] It will leave the Solar System in the direction of Telescopium.[30] 2I/Borisov has passed within 5.7 light-years of the binary star system Kruger 60 (13.18 light-years away, in Cepheus) at a low velocity of 3.4 km/s around a million years ago.[31]
If it only passed within 5.7 light-years of Kruger 60 (a low mass system of two RD stars) how could it be said to have been from that system? That's not nearly close enough, I would think.

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Re: JPL: Newly Discovered Comet Is Likely Interstellar Visitor

Post by neufer » Sat Nov 09, 2019 8:58 pm

BDanielMayfield wrote:
Sat Nov 09, 2019 6:13 pm
2I/Borisov has passed within 5.7 light-years of the binary star system Kruger 60 (13.18 light-years away, in Cepheus) at a low velocity of 3.4 km/s around a million years ago.
If it only passed within 5.7 light-years of Kruger 60 (a low mass system of two RD stars) how could it be said to have been from that system? That's not nearly close enough, I would think.
I suppose Kruger 60 could maintain a rarefied Oort cloud out to 360,000 AU
(where the escape velocity would only be ~47 m/s).

"Comets" could easily be kicked out of such a distant Oort cloud halo
but most should end up with relative velocities of ~47 m/s not 3,430 m/s.

(Note that a million years ago both 2I/Borisov and the binary star system Kruger 60 were over 100 light-years away. A miscalculation of 2I/Borisov incoming trajectory could easily place it near the center of the Kruger 60 binary which could well have flung it out at such a velocity.)
https://en.wikipedia.org/wiki/Kruger_60 wrote:
<<Kruger 60 (DO Cephei) is a binary star system located 13.15 light-years from the Sun. These red dwarf stars orbit each other every 44.6 years.
Component A has about 27% of the Sun's mass and 35% of the Sun's radius. Component B has about 18% of the Sun's mass and 24% of the Sun's radius. On average, the two stars are separated by 9.5 AUs, which is roughly the average distance of Saturn from the Sun. However, their eccentric mutual orbit causes their distance to vary between 5.5 AUs at periastron, to 13.5 at apastron.

Kruger 60 has been proposed as the origin of interstellar comet 2I/Borisov by Dybczyński, Królikowska, and Wysoczańska. These authors have from other work a list of stars and stellar systems that can potentially act as perturbers of the Oort cloud comets, and searched it for a past close proximity of 2I/Borisov at a very small relative velocity. While hampered by continuing uncertainty about the orbit of 2I/Borisov and particularly its non-gravitational acceleration (due to cometary outgassing), they reach a conclusion that that 1 Myr ago 2I/Borisov passed Kruger 60 at a small distance of 1.74 pc while having an extremely small relative velocity of 3,430 m/s. Perturbations of the 2I/Borisov's incoming orbit altered the intersection distance with relatively small changes in the relative velocity. At the time of publication, the results were considered preliminary as the orbit of 2I/Borisov was still being improved by new observations.>>
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Yale: New Image Offers Close-up View of Interstellar Comet

Post by bystander » Thu Nov 28, 2019 12:34 am

New Image Offers Close-up View of Interstellar Comet
Yale University | 2019 Nov 26
Yale astronomers have taken a new, close-up image of the interstellar comet 2I/Borisov.

2I/Borisov, first spotted this summer, continues to draw nearer to Earth and will reach its closest approach — about 190 million miles — in early December. Researchers believe the comet formed in a solar system beyond ours and was ejected into interstellar space as a consequence of a near-collision with a planet in its original solar system.

Yale astronomers Pieter van Dokkum, Cheng-Han Hsieh, Shany Danieli, and Gregory Laughlin captured the image Nov. 24 using the W.M. Keck Observatory’s Low-Resolution Imaging Spectrometer in Hawaii. They’ve also created an image that shows how the comet would look alongside planet Earth.

According to van Dokkum the comet’s tail, shown in the new image, is nearly 100,000 miles long, which is 14 times the size of Earth. “It’s humbling to realize how small Earth is next to this visitor from another solar system,” van Dokkum said.

Laughlin noted that 2I/Borisov is evaporating as it gets closer to Earth, releasing gas and fine dust in its tail. “Astronomers are taking advantage of Borisov’s visit, using telescopes such as Keck to obtain information about the building blocks of planets in systems other than our own,” Laughlin said.

The solid nucleus of the comet is only about a mile wide. As it began reacting to the Sun’s warming effect, the comet has taken on a “ghostly” appearance, the researchers said.
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