‘Unexpected’ space traveler defies theories about origin of solar system

Posted: December 19, 2022 by oldbrew in Astrophysics, research

Solar system cartoon [NASA]

The theorised Oort Cloud in the outer solar system seems not to consist entirely of what was theorised to be there. This is described by one researcher as ‘a complete game changer’.
– – –
Researchers from Western have shown that a fireball that originated at the edge of the solar system was likely made of rock, not ice, challenging long-held beliefs about how the solar system was formed, says Phys.org.

Just at the edge of our solar system and halfway to the nearest stars is a collection of icy objects sailing through space, known as the Oort Cloud.

Passing stars sometimes nudge these icy travelers towards the sun, and we see them as comets with long tails.

Scientists have yet to observe any objects in the Oort Cloud directly, but everything detected so far coming from its direction has been made of ice.

Theoretically, the very basis of understanding our solar system’s beginnings is built upon the foundation that only icy objects exist in these outer reaches and certainly, nothing made of rock.

This changed last year when an international team of scientists, stargazers, and professional and amateur astronomers led by Western meteor physicists captured images and videos of a rocky meteoroid that flew through the skies over central Alberta as a dazzling fireball.

The researchers have since concluded all signs point to the object’s origin being smack dab in the middle of the Oort Cloud.

The findings were published in Nature Astronomy.

“This discovery supports an entirely different model of the formation of the solar system, one which backs the idea that significant amounts of rocky material co-exist with icy objects within the Oort cloud,” said Denis Vida, a Western meteor physics postdoctoral researcher.

“This result is not explained by the currently favored solar system formation models. It’s a complete game changer.”

Full article here.
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Study: Direct measurement of decimetre-sized rocky material in the Oort cloud

  1. jb says:

    “everything detected so far coming from its direction has been made of ice.”

    Determined how? Its my understanding that every visit to an asteroid so far has shown no ice, but solid rock.

  2. oldbrew says:

    jb — In the study abstract they refer to rocky meteoroids, not asteroids.

  3. P.A.Semi says:

    This rather seems like archeologists finding a teeth are speculating, how fast did that creature run or fly…

    So from the trajectory of a fireball in Earth’s sky they recognized, that it comes from Oort cloud and not from Asteroid Belt or other bunch of space debris around Earth ?

    Halfway to nearest star is 2 light years, it’s certainly too far for anything to come here, far after boundary of Solar system… Passing stars? Any recent example?


  4. Ned Nikolov, Ph.D. says:


    I agree with you, this article seems to make some strange assertions. But the assumption that the Oort Cloud consists of icy objects is an interesting one, since it brings home the idea that water is perhaps more common in the Solar System than most people think. However, water only appears in liquid form on Earth, because the physical conditions in terms Earth’s proximity to the Sun and atmospheric pressure allow it…

  5. oldbrew says:

    They can’t be sure what the Oort Cloud consists of, at least until they can prove there is an Oort Cloud.

    The Oort cloud is a theoretical cloud of predominantly icy solid objects that are believed to surround the Solar System at distances ranging from 2.000 to 200.000 AU.

    The Oort cloud is yet to be directly observed, but many pieces of evidence point to its existence in the far reaches of the Solar System, thus surrounding us.
    . . .
    With the advancement of technology, it may become possible to finally observe the Oort cloud and prove its existence, and since its existence is in question, the mystery will forever bind us to further explore and solve this paradox.


    (Read as: 2,000 to 200,000 AU)

    NB since the Oort Cloud is believed to surround the solar system, knowing the trajectory of an object has limited value? Looking at the NASA cartoon in the post, what does ‘everything detected so far coming from its direction has been made of ice’, or ‘smack dab in the middle of the Oort Cloud’, mean? A long way away can be any direction, and the Oort cloud looks like a doughnut shape.

    NASA adds it is also believed to be a “giant spherical shell” surrounding the rest of the solar system, way beyond the outer reaches of the Kuiper Belt and the orbit of Pluto.

  6. Damian says:

    The Oort Cloud is theorised to exist as a sticking plaster over things that do exist that the nebular hypothesis can’t explain. Any water in the Earth should have been boiled off during its creation so it’s hypothesised that this water was delivered by icy comets from the Oort. The planet’s varying rates of rotation and axial tilt are also hypothesised to be the result of multiple impacts.

  7. oldmanK says:

    Quote part “a fireball that originated at the edge of the solar system was likely made of rock, not ice”
    Can ice make a fireball?

  8. oldbrew says:

    oldmanK – they call it ‘outgassing’ if it’s (believed to be) a comet…

    But they also say comets can generate meteor showers…

    Bright meteors can generate fireballs…

    Fireballs and bolides are astronomical terms for exceptionally bright meteors that are spectacular enough to to be seen over a very wide area.

  9. oldmanK says:

    oldbrew- I do not think ‘outgassing’ can be in any way similar to fireball.

    I did observe a fireball once. In daylight, at about 4pm summer, did not light the sky and very noisy. A seething mass of material, like a ball of molten lava. Very large, low in the sky and disappeared over the horizon towards Africa. Any ice originally in it would have been evaporated in its initial stage in its approach in the atmosphere, long before the rest melted in the heat generated and then became a fireball.

  10. oldbrew says:

    Comet of the month: C/2022 E3 (ZTF)
    – – –
    Discovered in March 2022 by the Zwicky Transient Facility, Comet ZTF is falling in from the outer solar system. Perihelion (closest approach to the sun) will occur on Jan. 12, 2023, at a distance of 1.11 AU. Closest approach to Earth follows on Feb. 1, 2023, at a distance of 0.28 AU. Between those two dates, the comet could hit magnitude 6, technically visible to the unaided eye.

    The two tails Jaeger saw are the dust tail and the ion tail. The ion tail is made of gas and is blown directly away from the sun by the solar wind. The heavier dust tail is curved and more closely traces the comet’s orbit.


  11. stpaulchuck says:

    who said the “ice” is water ice? Any of the gaseous elements can freeze out in space and some common combos like ammonia are known to exist as liquids in our planetary system but might freeze out in deep space.

  12. oldbrew says:


    The nature of the icy material accreted by comets during their formation in the outer regions of the protosolar nebula (PSN) is a major open question in planetary science.


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