Tag: Oumuamua

A new plan to send a probe to interstellar object Oumuamua

9:55 am

Project Lyra about to rendezvous with Oumuamua
Click to watch the animation.

Scientists have proposed a project to send an unmanned probe to Oumuamua, using the Earth, Jupiter, and then the Sun to slingshot onto a path that would catch up with the interstellar object on its journey leaving the solar system in the mid-2050s.

The project, dubbed Lyra, was first proposed in 2023. The scientists have now revised the plan to account for the greater speeds needed to catch up with Oumuamua as it continues to move away from us. It is still within the solar system, but it is moving away very fast.

The graphic to the right, a screen capture of an animation at the link, shows the spacecraft as it finally approaches the interstellar object in 2055. To get there it would launch in the early 2030s, slingshot past the Earth to reach Jupiter, which would then slow it down so that it would fall back to the Sun, passing it by less than 450,000 miles, which would slingshot it out to Oumuamua (with the help of an additional engine burn). To survive the close solar approach it would use the same technology used by the Parker Solar Probe, which has already successfully flown that close to the Sun.

It seems this is an entirely worthwhile project, since Oumuamua continues to baffle scientists as to its nature. While most belief it is a natural but very unusual interstellar asteroid, none can dismiss the possibility that it instead an alien spacecraft. The data precludes nothing. Getting close to it seems worthwhile, no matter what.

For me, that rendezvous will happen when I would be 102 years old. I don’t think I’ll be here to see it.

20 comments

Oumuamua wasn’t made of hydrogen ice

9:45 am

The uncertainty of science: According to a new paper published today, Oumuamua wasn’t a hydrogen iceberg as proposed by other scientists earlier this year.

Traveling at a blistering speed of 196,000mph in 2017, ‘Oumuamua was first classified as an asteroid, and when it later sped up, was found to have properties more akin to comets. But the 0.2km radius interstellar object didn’t fit that category, either, and its point of origin has remained a mystery. Researchers focused on the giant molecular cloud (GMC) W51—one of the closest GMCs to Earth at just 17,000 light years away—as a potential point of origin for ‘Oumuamua, but hypothesize that it simply could not have made the journey intact. “The most likely place to make hydrogen icebergs is in the densest environments of the interstellar medium. These are giant molecular clouds,” said Loeb, confirming that these environments are both too far away and are not conducive to the development of hydrogen icebergs.

The hydrogen iceberg theory was for many reasons very very speculative, and not very convincing, which is why I never posted a link to it when it became clickbait for the mainstream press several months ago. The object’s behavior as it zipped through the solar system, combined with its elongated shape, still leave us with questions. While some scientists have definitely stated it could not have been an alien spacecraft, that likely conclusion remains as uncertain as the theory that it was a hydrogen iceberg.

The only way we will definitely know is to go and look at it. And such a mission remains possible, with launch dates in 2021, 2022, or 2023, with technology we presently have, if we were to move fast.

One comment

Astronomers declare: Oumuamua was not an alien spacecraft!

7:36 pm

The uncertainty of science: An international team of astronomers have announced that after much consultation and discussion it is their conclusion that the interstellar object Oumuamua that zipped through the solar system in 2017 was a natural object, not an alien spacecraft.

[A] review of all the available evidence by an international team of 14 experts strongly suggests that ʻOumuamua has a purely natural origin. The research team reported their findings in the July 1, 2019, issue of the journal Nature Astronomy.

“We have never seen anything like ʻOumuamua in our solar system,” said Dr. Matthew Knight, the team leader from the University of Maryland “but our preference is to stick with analogs we know, unless or until we find something unique. The alien spacecraft hypothesis is a fun idea, but our analysis suggests there is a whole host of natural phenomena that could explain it.”

It is perfectly reasonable for these scientists to choose the simplest and most likely explanation for Oumuamua, which would be a natural object. Moreover, their conclusion does fit the data we have reasonable well.

At the same time, for anyone to assume there is any certainty to this conclusion would be a grave mistake. It is merely the best guess, based on the available but somewhat limited data. The data however does not preclude more exotic explanations. Nothing is certain.

Leave a comment

Null result from Spitzer suggests Oumuamua was small

1:43 pm

The uncertainty of science: The inability of the infrared Spitzer Space Telescope to detect the interstellar object Oumuamua as it exited the solar system suggests the object is small.

The fact that ‘Oumuamua was too faint for Spitzer to detect sets a limit on the object’s total surface area. However, since the non-detection can’t be used to infer shape, the size limits are presented as what ‘Oumuamua’s diameter would be if it were spherical. Using three separate models that make slightly different assumptions about the object’s composition, Spitzer’s non-detection limited ‘Oumuamua’s “spherical diameter” to 1,440 feet (440 meters), 460 feet (140 meters) or perhaps as little as 320 feet (100 meters). The wide range of results stems from the assumptions about ‘Oumuamua’s composition, which influences how visible (or faint) it would appear to Spitzer were it a particular size.

The new study also suggests that ‘Oumuamua may be up to 10 times more reflective than the comets that reside in our solar system – a surprising result, according to the paper’s authors.

These results fit the models that explain Oumuamua’s fluctuations in speed as caused by the out gassing of material, like a comet. They also do not contradict the recent hypothesis that the object might have been an alien-built light sail.

The simple fact is that we do not have enough data to confirm any of these theories.

3 comments

Oumuamua might be artificial lightsail

3:45 pm

A new analysis of the velocity and path of the interstellar object Oumuamua suggests it might be an artificial lightsail.

The study, which was posted online earlier this month, suggests that Oumuamua’s strange “excess acceleration” could be artificial in nature, as it has been implied that it is not an active comet. “Considering an artificial origin, one possibility is that ‘Oumuamua is a lightsail, floating in interstellar space as a debris from an advanced technological equipment,” researchers wrote in the paper.

The paper continues: “Lightsails with similar dimensions have been designed and constructed by our own civilization, including the IKAROS project and the Starshot Initiative. The lightsail technology might be abundantly used for transportation of cargos between planets or between stars.”

They even theorized that Oumuamua “may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization,” though that scenario was called “exotic.”

All of this is speculation. However, that the object is moving faster than expected, based on the initial data of its path, is quite intriguing. The authors of the paper concluded that the excess speed was caused by “solar radiation pressure.” They also calculated that for the light pressure to cause that increase in speed as it moves away requires it to have a large surface area.

The observations are not sufficiently sensitive to provide a resolved image of ‘Oumuamua, and one can only speculate on its possible geometry and nature. Although periodic variations in the apparent magnitude are observed, there are still too many degrees of freedom (e.g., observing angle, non-uniform reflectively, etc.) to definitely constrain the geometry. The geometry should not necessarily be that of a planar sheet, but may acquire other shapes, e.g., involving a curved sheet, a hollow cone or ellipsoidal, etc. Depending on the geometry our estimated value for the mass-to-area ratio will change, but the correction is typically of order unity.

They then speculate the possibility of the object being an interstellar probe.

5 comments

New observations of interstellar Oumuamua give it comet-like properties

11:10 am

The uncertainty of science: New observations of interstellar object Oumuamua suggest that it is a comet, not an asteroid.

[B]y combining data from the NASA/ESA Hubble Space Telescope, the Canada-France-Hawaii Telescope, ESO’s Very Large Telescope and the Gemini South Telescope, an international team of astronomers has found that the object is moving faster than predicted. The measured gain in speed is tiny and `Oumuamua is still slowing down because of the pull of the Sun — just not as fast as predicted by celestial mechanics.

The team, led by Marco Micheli (European Space Agency) explored several scenarios to explain the faster-than-predicted speed of this peculiar interstellar visitor. The most likely explanation is that `Oumuamua is venting material from its surface due to solar heating — a behaviour known as outgassing. The thrust from this ejected material is thought to provide the small but steady push that is sending `Oumuamua hurtling out of the Solar System faster than expected — as of 1 June, it is travelling with about 114 000 kilometres per hour.

Such outgassing is a typical behaviour for comets and contradicts the previous classification of `Oumuamua as an interstellar asteroid. “We think this is a tiny, weird comet,” comments Marco Micheli. “We can see in the data that its boost is getting smaller the farther away it travels from the Sun, which is typical for comets.”

If I was to speculate wildly, I could also wonder if maybe the aliens on board have decided they needed to get the heck out of here as fast as possible, and have fired their thrusters to make that happen.

5 comments

Scientists theorize that Oumuamua came from a binary star system

8:17 am

Based on statistics and computer modeling, some scientists believe that the interstellar object Oumuamau likely came from stellar binary system.

For the new study, published in the journal Monthly Notices of the Royal Astronomical Society, Jackson and his co-authors set about testing how efficient binary star systems are at ejecting objects. They also looked at how common these star systems are in the Galaxy. They found that rocky objects like ‘Oumuamua are far more likely to come from binary than single star systems. They were also able to determine that rocky objects are ejected from binary systems in comparable numbers to icy objects.

Their conclusion does make sense, though any good scientist would retain a gigantic sense of skepticism. While it is statistically reasonable to conclude that a majority of interstellar objects should come from binary systems, there is no guarantee that Oumuamua in particular did so. Even if the odds were one in a million, there is always that one, and the universe often seems prone to fooling us.

One comment

Interstellar object Oumuamua tumbling chaotically

8:46 am

A new analysis of the data obtained when the interstellar object Oumuamua flew through the solar system in October 2016 suggests that it is tumbling in a chaotic manner, and that the surface is spotty.

Straight away, they discovered that ‘Oumuamua wasn’t spinning periodically like most of the small asteroids and bodies that we see in our solar system. Instead, it is tumbling, or spinning chaotically, and could have been for many billions of years.

While it is difficult to pinpoint the exact reason for this, it is thought that `Oumuamua impacted with another asteroid before it was fiercely thrown out of its system and into interstellar space. Dr Fraser explains: “Our modelling of this body suggests the tumbling will last for many billions of years to hundreds of billions of years before internal stresses cause it to rotate normally again.

To me, this data settles the question about whether Oumuamua is not an artificial structure. It is not. If it were, an impact that would have caused this kind of tumbling would have almost certainly destroyed it. Instead, it likely broke the original bolide up, producing many fragments, including Oumuamua and its elongated shape.

As for the object’s spottiness:

Dr Fraser explains: “Most of the surface reflects neutrally but one of its long faces has a large red region. This argues for broad compositional variations, which is unusual for such a small body.”

It is really a shame we couldn’t get a closer look before it sped away.

Leave a comment

Oumuamua has a thick carbon crust built up by its interstellar travel

8:59 am

New results of observations of the interstellar object Oumuamua suggest that it has a thick crust of organic carbon soot that was slowly built up during the millions of years it traveled between the stars.

New observations of the cigar-shaped body found evidence for a deep surface layer that formed when organic ices – such as frozen carbon dioxide, methane and methanol – that make up the object were battered by the intense radiation that exists between the stars.

…The deep outer crust may have formed on the body over millions or even billions of years and gives ‘Oumuamua a dark red colour, according to researchers who investigated the object with the William Herschel Telescope on La Palma in the Canary Islands and the European Southern observatory in Chile’s Atacama desert.

There have been a slew of news stories today about these results, all focusing not on the crust of the object, which tells us nothing really about its interior, but on one quote by one scientist from the press release, who theorized — based on zero data — that the interior of the object could be icy. From this quote I have seen at least a half dozen stories exclaiming that Oumuamua thus could be like a comet, based on no information at all.

All we have learned is that traveling for a long time in interstellar space causes a build up of carbon-rich materials on the surface of an object. What might be hidden under that crust remains entirely unknown. It could be icy, but we don’t know that.

5 comments

Breakthrough Listen to observe Ourmuamua

10:47 am

Breakthrough Listen, one of billionaire Yuri Milner’s Breakthrough initiatives, is going to do an observation campaign of the interstellar object Ourmuamua using the Green Bank Radio telescope.

It has a highly unusual structure for an asteroid – an elongated cigar shape, hundreds of meters in length but with width and height perhaps only one tenth as long.

Researchers working on long-distance space transportation have previously suggested that a cigar or needle shape is the most likely architecture for an interstellar spacecraft, since this would minimize friction and damage from interstellar gas and dust. While a natural origin is more likely, there is currently no consensus on what that origin might have been, and Breakthrough Listen is well positioned to explore the possibility that ‘Oumuamua could be an artifact.

Listen’s observation campaign will begin on Wednesday, December 13 at 3:00 pm ET. Using the Robert C. Byrd Green Bank Telescope, it will continue to observe ‘Oumuamua across four radio bands, from 1 to 12 GHz. Its first phase of observations will last a total of 10 hours, divided into four “epochs” based on the object’s period of rotation.

If anything, this observation will provide us more information about Ourmuamua itself, which unfortunately is very limited because the object was already on its way out when it was discovered.

3 comments

A mission to interstellar object Oumuamua?

11:31 am

A private company and a volunteer group dedicated to promoting interstellar travel have written a paper [pdf] exploring the possibility of launching a mission to fly past the interstellar object Oumuamua, now speeding out of our solar system.

As they note in the paper’s abstract,

Can such objects be intercepted? The challenge of reaching the object within a reasonable timeframe is formidable due to its high heliocentric hyperbolic excess velocity of about 26 km/s; much faster than any vehicle yet launched. This paper presents a high-level analysis of potential near-term options for such a mission. Launching a spacecraft in a reasonable timeframe of 5-10 years requires a hyperbolic solar system excess velocity between 33 to 76 km/s for mission durations between 30 to 5 years. Different mission durations and their velocity requirements are explored with respect to the launch date, assuming direct impulsive transfer to the intercept trajectory. Several technology options are outlined, ranging from a close solar Oberth Maneuver using chemical propulsion, and the more advanced options of solar and laser sails. To maximize science return decelerating the spacecraft at ’Oumuamua is highly desirable, due to the minimal science return from a hyper-velocity encounter. It is concluded that although reaching the object is challenging, there seem to be viable options based on current and near-term technology.

The paper even considers the use of SLS or SpaceX’s Big Falcon Rocket.

8 comments