Sending a Tiny Telescope Past Saturn Could Solve Some of the Biggest Mysteries of the Universe

Cassini and Saturn

A telescope in the outer solar system would be able to do unique science that is impossible closer to the Sun. (Representative image showing the Cassini spacecraft near Saturn.

Dozens of space-based telescopes operate near Earth and provide incredible images of the universe. But imagine a telescope far away in the outer solar system, 10 or even 100 times farther from the Sun than Earth. The ability to look back at our solar system or peer into the darkness of the distant cosmos would make this a uniquely powerful scientific tool.

I’m an astrophysicist who studies the formation of structure in the universe. Since the 1960s, scientists like me have been considering the important scientific questions we might be able to answer with a telescope placed in the outer solar system.

So what would such a mission look like? And what science could be done?

Telescope Solar System

Where a telescope is located matters nearly as much as its power. In many cases, the farther from the Sun, the better. Credit: Beinahegut/WikimediaCommons

A tiny telescope far from home

The scientific strength of a telescope far from Earth would come primarily from its location, not its size. Plans for a telescope in the outer solar system would put it somewhere beyond the orbit of Saturn, roughly a billion or more miles from Earth.

We’d need only send a very small telescope – with a lens roughly the size of a small plate – to achieve some truly unique astrophysical insights. Such a telescope could be built to weigh less than 20 pounds (9 kilograms) and could be piggybacked on virtually any mission to Saturn or beyond.

Though small and simple compared with telescopes like Hubble or James Webb, such an instrument operating away from the bright light of the Sun could make measurements that are difficult or outright impossible from a vantage point near the Earth.

Sun Disc

The Sun has a disc of dust and gas surrounding it, much like the pinkish haze seen in this image and graphical representation of a nearby red dwarf star and its dust cloud. Credit: NASA/ESA/J. Debes

Outside looking in

Unfortunately for astronomers, getting a selfie of the solar system is a challenge. But being able to see the solar system from an outside vantage point would reveal a lot of information, in particular about the shape, distribution and composition of the dust cloud that surrounds the Sun.

Imagine a street lamp on a foggy evening – by standing far away from the lamp, the swirling mists are visible in a way that someone standing under the streetlight could never see.

For years astrophysicists have been able to take images of and study the dust discs in solar systems around other stars in the Milky Way. But these stars are very far away, and there are limits to what astronomers can learn about them. Using observations looking back toward the Sun, astronomers could compare the shape, features and composition of these distant dust clouds with detailed data on Earth’s own solar system. This data would fill gaps in knowledge about solar dust clouds and make it possible to understand the history of production, migration and destruction of dust in other solar systems that there is no hope of traveling to in person.

Hubble Ultra Deep Field of Galaxies

The universe is full of galaxies – as seen in this image called the Hubble Ultra Deep Field – and measuring the cumulative light from these is hard to do from Earth. Credit: NASA, ESA, and S. Beckwith (STScI) and the HUDF Team

Deep darkness of space

Another benefit of placing a telescope far from the Sun is the lack of reflected light. The disc of dust in the plane of the planets reflects the Sun’s light back at Earth. This creates a haze that is between 100 and 1,000 times brighter than light from other galaxies and obscures views of the cosmos from near Earth. Sending a telescope outside of this dust cloud would place it in a much darker region of space making it easier to measure the light coming from outside the solar system.

Once there, the telescope could measure the brightness of the ambient light of the universe over a wide range of wavelengths. This could provide insights into how matter condensed into the first stars and galaxies. It would also enable researchers to test models of the universe by comparing the predicted sum of light from all galaxies with a precise measurement. Discrepancies could point to problems with models of structure formation in the universe or perhaps to exotic new physics.

Gravitational Lensing Example

From far enough away, it would be possible to use the Sun as a giant lens, similar to the gravitational lensing seen here as light from a distant blue galaxy is bent around a nearer orange galaxy seen in the center. Credit: ESA/Hubble/NASA

Into the unknown

Finally, increasing a telescope’s distance from the Sun would also allow astronomers to do unique science that takes advantage of an effect called gravitational lensing, in which a massive object distorts the path light takes as it moves past an object.

One use of gravitational lensing is to search for and weigh rogue planets – planets that roam interstellar space after being ejected from their home solar systems. Since rogue planets don’t emit light on their own, astrophysicists can look for their effect on the light from background stars. To differentiate between the distance of the lensing object and its mass requires observations from a second location far from Earth.

Gravitational Lensing Animation

Gravitational lensing caused by a planet passing in front of a distant star will bend light from that star, and that can also be used to detect dark planets that have been ejected from solar systems. Credit: NASA Ames/JPL-Caltech/T. Pyle

In 2011, scientists used a camera on the EPOXI mission to the asteroid belt to discover and weigh a Neptune-sized object floating free among stars in the Milky Way galaxy. Only a few rogue planets have been found, but astronomers suspect they are very common and could hold clues to the formation of solar systems and prevalence of planets around stars.

But perhaps the most interesting use for a telescope in the outer solar system would be the potential to use the gravitational field of the Sun itself as a giant lens. This kind of measurement may allow astrophysicists to actually map planets in other star systems. Perhaps one day we will be able to name continents on an Earth-like planet around a distant star.

Coming soon?

Since Pioneer 10 became the first human-made object to cross Jupiter’s orbit in 1973, there have been only a handful of astrophysical studies done from beyond the orbit of Earth. Missions to the outer solar system are rare, but many teams of scientists are doing studies to show how an extrasolar telescope project would work and what could be learned from one.

Every 10 years or so, leaders in the astrophysics and astronomy fields gather to set goals for the following decade. That plan for the 2020s is scheduled to be released on November 4, 2021. In it, I expect to see discussions about the next telescope that could revolutionize astronomy. Taking a telescope to the outer solar system, while ambitious, is well within the technological ability of NASA or other space agencies. I hope that one day soon a tiny telescope out on a lonely mission in dark reaches of the solar system will provide us incredible insights into the universe.

Written by Michael Zemcov, Associate Professor of Physics, Rochester Institute of Technology.

This article was first published in The Conversation.The Conversation

6 Comments on "Sending a Tiny Telescope Past Saturn Could Solve Some of the Biggest Mysteries of the Universe"

  1. larry hanna m.d. retired | November 15, 2021 at 4:24 pm | Reply

    THIS IS A SCINTILLATING THRILLING CONCEPT WITH SO MANY ADVANTAGES AND LESSONS TO BE ABSORBED. Thank the author for pointing the way how to add tons of info to the data base. Carl Sagan’s special star is winking saying “hurrah” for my species, getting focused on those “billions and billions” he used to talk about. Start a fund; I can always SPARE SOMETHING FOR A PROJECT LIKE THIS. iF George 3 could fund Herschel’s telescope, so that he and his sister could locate Uranus, then we can do this!

  2. I have seen other articles suggesting the sun as a gravitational lens using a telescope several times the distance of neptune. Can the moon or another body without atmosphere be used in a similar albeit less powerful fashion?

  3. Babu G. Ranganathan | November 16, 2021 at 7:40 am | Reply

    Babu G. Ranganathan*
    (B.A. Bible/Biology)

    JUST BECAUSE SCIENCE CAN EXPLAIN how an airplane works doesn’t mean that no one designed or made the airplane. And just because science can explain how life or the universe works doesn’t mean there was no Designer and Maker behind them.

    Natural laws may explain how the order in the universe works and operates, but mere undirected natural laws cannot explain the origin of that order. Once you have a complete and living cell then the genetic code and biological machinery exist to direct the formation of more cells from raw materials such as amino acids and other chemicals, but how could life or the cell have naturally originated when no directing code and mechanisms existed in nature? Read my Internet article: HOW FORENSIC SCIENCE REFUTES ATHEISM.

    WHAT IS SCIENCE? Science simply is knowledge based on observation. No human observed the universe coming by chance or by design, by creation or by evolution. These are positions of faith. The issue is which faith the scientific evidence best supports.

    SCIENCE SHOWS THAT THE UNIVERSE CANNOT BE ETERNAL because it could not have sustained itself eternally due to the law of entropy (increasing and irreversible net energy decay, even in an open system). Even a hypothetical oscillating universe could not continue to oscillate eternally! Einstein’s General Theory of Relativity shows that space, matter, and time all are physical and all had a beginning. Space even produces particles because it’s actually something, not nothing. What about the Higgs boson (the so-called “God Particle”)? The Higgs boson, even if it existed, would not have created mass from nothing, but rather it would have converted energy into mass. Einstein showed that all matter is some form of energy. Even time had a beginning! Time is not eternal.

    The law of entropy doesn’t allow the universe to be eternal. If the universe were eternal, everything, including time (which modern science has shown is as physical as mass and space), would have become totally entropied by now and the entire universe would have ended in a uniform heat death a long, long time ago. The fact that this hasn’t happened already is powerful evidence for a beginning to the universe.

    Popular atheistic scientist Stephen Hawking admits that the universe had a beginning and came from nothing but he believes that nothing became something by a natural process yet to be discovered. That’s not rational thinking at all, and it also would be making the effect greater than its cause to say that nothing created something. The beginning had to be of supernatural origin because science teaches us from the First Law of Thermodynamics that natural laws and processes do not have the ability to bring something into existence from nothing.

    The supernatural origin of the universe cannot be proved by science but science points to a supernatural intelligence and power for the origin and order of the universe. Where did God come from? Obviously, unlike the universe, God’s nature doesn’t require a beginning.

    The disorder in the universe can be explained because of chance and random processes, but the order can be explained only because of intelligence and design.

    Gravity may explain how the order found in the precise and orderly courses of thousands of billions of stars is maintained, but gravity cannot explain the origin of that order.

    Some evolutionary astronomers believe that trillions of stars crashed into each other leaving surviving stars to find precise orderly orbits in space. Not only is this irrational, but if there was such a mass collision of stars then there would be a super mass residue of gas clouds in space to support this hypothesis. The present level of residue of gas clouds in space doesn’t support the magnitude of star deaths required for such a hypothesis. And, as already stated, the origin of stars cannot be explained by the Big Bang because of the reasons mentioned above. It’s one thing to say that stars may decay and die into random gas clouds, but it is totally different to say that gas clouds form into stars.

    Even the father of Chaos theory admitted that the “mechanisms” existing in the non-living world allow for only very rudimentary levels of order to arise spontaneously (by chance), but not the kind or level of order we find in the structures of DNA, RNA, and proteins. Yes, individual amino acids have been shown to come into existence by chance but not protein molecules which require that the various amino acids be in a precise sequence just like the letters found in a sentence.

    Some things don’t need experiment or scientific proof. In law there is a dictum called prima facie evidence. It means “evidence that speaks for itself.”

    An example of a true prima facie would be if you discovered an elaborate sand castle on the beach. You don’t have to experiment to know that it came by design and not by the chance forces of wind and water.

    If you discovered a romantic letter or message written in the sand, you don’t have to experiment to know that it was by design and not because a stick randomly carried by wind put it there. You naturally assume that an intelligent and rational being was responsible.

    It’s interesting that Carl Sagan would have acknowledged sequential radio signals in space as evidence of intelligent life sending them, but he wouldn’t acknowledge the sequential structure of molecules in DNA (the genetic code) as evidence of an intelligent Cause. Read my popular Internet article, HOW DID MY DNA MAKE ME.

    I encourage all to read my popular Internet articles:


    Visit my latest Internet site: THE SCIENCE SUPPORTING CREATION (This site answers many arguments, both old and new, that have been used by evolutionists to support their theory)


    *I have given successful lectures (with question and answer period afterwards) defending creation before evolutionist science faculty and students at various colleges and universities. I’ve been privileged to be recognized in the 24th edition of Marquis “Who’s Who in The East” for my writings on religion and science.

  4. That outer solar system telescope should be looking two ways ie one lens looking solar system and other len looking beyond solar system in its orbital plane in which case the unit does have to turn 180°,the telescope will send 2 informations down to earth,one of solar system and other of beyond it ie whatever it sees at that point of time.l’m not a scientist, but, this can done.

  5. @Morgan – the gravitational lensing power is determined by the mass of the object. Since the moon is smaller than the sun, the focal point would is much further away.

  6. I looked and the Nov 8th report of 2020s priorities include 4 space telescopes – Lynx, LUVOIR, HabEx and Origins – but none fit author Michael Zemcov’s description.

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