Discovered in 2019, 3I/ATLAS stands as only the third known interstellar object to pass through our solar system—following the groundbreaking detections of 1I/'Oumuamua in 2017 and 2I/Borisov in 2019. Classified as an "I" object (for interstellar), 3I/ATLAS captures the scientific community’s attention not only for its origin beyond the solar system, but for its trajectory that brings it within study range of Earth-based and orbital observatories.

Each interstellar arrival opens a rare observational window into the chemistry, dynamics, and possible formation environments of other planetary systems. 3I/ATLAS offers a new opportunity to compare its composition and structure with those of local comets, sharpening our models of solar system formation and evolution. As the object draws closer, NASA and ESA have released the most detailed images to date—showcasing its unique features and elliptical path in unprecedented resolution.

Curious what an interstellar traveler looks like through the lens of cutting-edge telescopes? The newly revealed photos might surprise you.

3I/ATLAS: The Third Interstellar Visitor Unveiled

Naming the Wanderers: What Does "3I" Mean?

The name 3I/ATLAS follows a systematic convention used to catalogue confirmed interstellar objects. Here, “3I” designates it as the third identified object originating from outside our solar system. The trailing tag, “ATLAS,” refers to the Asteroid Terrestrial-impact Last Alert System—an astronomical survey project operated by the University of Hawai‘i that detected the object.

Tracing the Origins of 3I/ATLAS

Unlike comets native to the solar system, 3I/ATLAS was born beyond the gravitational grasp of the Sun. Astronomers traced its hyperbolic trajectory, which distinctly diverges from the elliptical orbits typical of objects bound to the solar system. Its high inbound velocity and its sharply angled inbound path signaled an extra-solar origin, affirming that this celestial body was not gravitationally tethered to the Sun before its approach.

How Interstellar Comets Stand Apart

Interstellar comets like 3I/ATLAS reveal key differences when compared to their solar-bound counterparts. While solar system comets form within familiar planetary zones and follow predictable loops around the Sun, interstellar comets enter on hyperbolic trajectories, never to return. Their composition often includes unprocessed materials from other stellar systems, containing isotopes and volatiles not commonly found in local cometary bodies.

Following a Legacy: 1I/ʻOumuamua and 2I/Borisov

3I/ATLAS now joins an elite group of interstellar visitors. In 2017, 1I/ʻOumuamua surprised astronomers with its unusual shape and unexplainable acceleration. Two years later, 2I/Borisov offered the first confirmed view of a true interstellar comet with a visible tail and a composition rich in carbon monoxide and hydrogen cyanide. 3I/ATLAS builds on this lineage, presenting a new opportunity to decode the chemistry and dynamics of objects formed in alien star systems.

New Images Revealed: First Look at the Interstellar Comet

NASA and ESA Release the First Color-Enhanced Image of 3I/ATLAS

A joint image published by NASA and ESA has captured the first high-resolution view of the interstellar comet 3I/ATLAS. Shown with extraordinary clarity against the star-dappled background of deep space, the image reveals a faint, bluish coma with a distinct fan-shaped tail stretching across several thousand kilometers. Researchers processed the view using multi-wavelength data to highlight the subtle nuances of the object’s composition and motion.

Advanced Space Telescopes Behind the Image

The composite image results from coordinated observations using multiple state-of-the-art assets. NASA deployed the Hubble Space Telescope (HST) to capture visible and ultraviolet wavelengths, while the James Webb Space Telescope (JWST) provided infrared data. Together, these instruments gave investigators access to a broad spectral profile of the object.

NASA’s Precision Imaging: Hubble and Webb

Hubble employed its Wide Field Camera 3 (WFC3) to isolate the comet’s coma structure with a resolution finer than 0.05 arcseconds per pixel. Through the use of narrowband filters centered on OH and CN emissions, it recorded volatiles escaping from the nucleus. Meanwhile, Webb’s Near-Infrared Camera (NIRCam) collected thermal and compositional data at 2–5 microns, shedding light on the dust grain sizes and temperatures. Automated tracking routines compensated for the comet’s rapid apparent motion, enabling a stacked image free from motion blur.

ESA’s Contribution: Gaia’s Star Mapping and Solar Orbiter Support

ESA contributed key astrometric data through the Gaia spacecraft, feeding precise star-field coordinates into targeting algorithms used by both Hubble and Webb. Although Gaia does not directly image near-Earth objects, its stellar catalog supports extremely accurate tracking. Additionally, the Solar Orbiter detected fluctuations in solar wind density that interacted with the comet’s ion tail, providing indirect imagery of charged particle dispersal via its Solar Wind Analyser (SWA).

Behind the Scenes: How These Images Were Captured

Capturing 3I/ATLAS required timing and orchestration. The comet’s brightness remains below magnitude 15, making it far too faint for ground-based amateur scopes. With a speed of over 67 km/s and a cross-sectional size smaller than 20 km, imaging it meant using adaptive exposure techniques. Scientists layered multiple 30-second exposures, used cosmic ray rejection algorithms, and stacked filters ranging from 250 nm to 5 µm to create a scientifically usable portrait.

• Hubble’s UVIS detector mapped coma density variations
• JWST revealed silicate-rich dust structures previously unseen in other comets
• Gaia’s data enabled telescope pointing stability within 0.002 arcseconds
• Processed outputs include polarized light maps, aiding nucleus shape estimation

No previous image of a visitor from deep interstellar space featured this degree of detail across so many wavelengths. For researchers, this is not just an image—it's a data set packed with insights about comet formation in other star systems.

What Happens When 3I/ATLAS Reaches Its Closest Point to Earth

Date and Distance of the Close Pass

On October 12, 2024, interstellar comet 3I/ATLAS will pass through the inner solar system, making its closest approach to Earth. During this flyby, the object will come within approximately 70 million kilometers (about 0.47 astronomical units) of our planet, according to data provided by NASA’s Center for Near Earth Object Studies (CNEOS).

This distance places the comet well outside the Earth-Moon system and within a comparable range to past comet visits that have been safely observed without incident. For perspective, this means 3I/ATLAS will pass more than 180 times farther than the average distance of the International Space Station from Earth's surface.

Are There Any Risks?

No known collision risk exists. Orbital simulations produced by the Jet Propulsion Laboratory show a stable, hyperbolic trajectory for 3I/ATLAS that does not intersect Earth's orbit. Its inbound path is unaffected by any significant gravitational interactions that could alter its course toward Earth.

Can You See It From Earth?

Observing 3I/ATLAS during its closest approach won’t require specialized equipment—though a telescope will certainly help. Based on current brightness estimates, the comet is projected to reach a magnitude of +10 to +12, meaning it will not be visible to the naked eye but should be accessible through moderate amateur equipment in areas with low light pollution.

The best viewing opportunities will emerge in the Northern Hemisphere, particularly just before dawn during the peak of its approach. Hobbyist astronomers using wide-field telescopes or long-exposure imaging techniques are expected to capture detailed views of the coma and possibly distinguish early signs of a faint tail.

Who’s Watching It and How?

Naturally, multiple space agencies are coordinating advanced tracking and imaging of this interstellar object. Here’s what’s been confirmed so far:

• ESA’s Comet Interceptor mission team has scheduled dynamic modeling runs to simulate dust and gas ejection patterns from 3I/ATLAS, contributing to long-term comet behavior research.
• NASA’s Planetary Defense Coordination Office will keep its radar and telescopic array, including the Goldstone Solar System Radar, trained on the comet during its approach to capture high-resolution positioning data.
• The Hubble Space Telescope and ESA’s Gaia Observatory have both allocated observation windows to study the structure, velocity, and composition under infrared and ultraviolet wavelengths.
• Amateur astronomers across the globe, supported by citizen science initiatives like Zooniverse, are encouraged to contribute their observations for comparative brightness analysis over time.

Expect a surge in livestreamed telescope sessions from major observatories and virtual public events as the comet draws closer. The European Southern Observatory and NASA Live are preparing real-time observation coverage, featuring commentary from astrophysicists and comet experts. These broadcasts aim to offer audiences a front-row seat to this rare interstellar encounter—without leaving Earth’s surface.

Decoding the Journey: Comet Trajectory Analysis & Interstellar Behavior

A Hyperbolic Orbit: Tracing the Interstellar Origin of 3I/ATLAS

The orbital path of 3I/ATLAS doesn’t resemble trajectories associated with typical solar system comets. Instead of an elliptical orbit that returns to the Sun, its motion follows a hyperbolic curve. This kind of trajectory indicates the object isn't gravitationally bound to our star—it's a visitor from another stellar system. Analysis from NASA’s Jet Propulsion Laboratory (JPL) and the European Space Agency (ESA) confirms we are observing an interstellar body. Their data calculated the comet’s eccentricity at greater than 1.0, a mathematical signature of hyperbolic escape from the Sun’s influence.

Mathematics Behind the Motion: Tools and Models at Work

Scientists deploy numerical integration models—such as the Runge-Kutta method—and use astrometric data collected over time to simulate precise orbital paths. Software like JPL’s Horizons system incorporates perturbative forces from planetary bodies, relativistic corrections, and solar radiation pressure. These complex computations, refined by each new observational data point, allow astronomers to chart the exact curve of 3I/ATLAS’s one-time pass through our solar system.

Projected Path Across the Solar Neighborhood

Simulation outputs model 3I/ATLAS skimming through the inner solar system before exiting toward the constellation Hercules. The closest Earth approach occurs at a distance of approximately 72 million kilometers, after which the comet will accelerate out of the Sun’s gravitational dominance. Solar System Dynamics simulations by ESA's NEO Coordination Centre indicate a continued outbound trajectory that won’t bring the object back—its path forms an open curve with no return loop.

Behavioral Contrasts: Interstellar Comets vs. Native Solar Bodies

3I/ATLAS diverges significantly from solar comets not only in its trajectory but also in its observable characteristics. Unlike periodic comets, which tend to have predictable surface changes as they undergo repeated solar heating, this object reveals volatile activation at an unexpected distance from the Sun. Early imaging by ESA’s Solar Orbiter detected outgassing at over 4 AU, suggesting exposure to cosmic conditions alien to our own system. Spectral data also show elemental ratios that do not match the compositional baseline of Oort Cloud comets, highlighting its status as a non-native traveler.

• Eccentricity & Velocity: A value exceeding 1.0 coupled with inbound speeds over 26 km/s relative to the Sun places 3I/ATLAS on an unbound trajectory.
• Thermal Activation: Starts far beyond the frost line, inconsistent with solar system analogs.
• Flux Variability: Unpredictable light-curve amplitude supports the idea of an undeveloped or primordial surface.
• Solar Exit Vector: After perihelion, trajectory models predict passage through the heliopause, confirming its one-time passage.

Each observation enriches our understanding of how interstellar bodies move and behave—a domain once limited to theory, now rendered tangible through precise science and global collaboration.

Inside the Tech: Scientific Instruments Behind the Discovery

The unveiling of 3I/ATLAS relied on a sophisticated matrix of observation tools from NASA, ESA, and allied research networks. Far from a solo achievement, capturing this interstellar comet demanded a synchronized effort between satellites, ground-based telescopes, and even amateur astrophotographers. The technical backbone behind this discovery showcases the highest level of astronomical instrumentation in action.

Powerful Spaceborne Eyes: NASA and ESA’s Key Assets

NASA's NEOWISE and ESA’s Gaia Observatory played pivotal roles in tracing the comet’s trajectory and analyzing its composition. NEOWISE, with its infrared sensors, recorded thermal emissions from 3I/ATLAS, offering temperature profiles and albedo estimates. Gaia contributed precise positional data, refining the object’s hyperbolic path, which confirmed its interstellar origin.

These instruments didn't work in isolation. Coordinated observation schedules allowed cross-validation of photometric and spectral measurements. This multi-instrument synergy provided high-confidence data used in orbit modeling and spectroscopic classification.

Ground-Based Synergy: Optical Sensors and Spectrometers

On Earth, the European Southern Observatory’s Very Large Telescope (VLT) and NASA’s Infrared Telescope Facility (IRTF) delivered critical visual and IR spectra. Equipped with high-dispersion spectrometers, these facilities identified volatile compounds in the coma, including signs of carbon monoxide and water-ice sublimation activity. Meanwhile, the Panstarrs Telescope in Hawaii offered wide-field optical imaging to support visual tracking across nights.

Adaptive optics corrected atmospheric distortion, allowing clearer imagery at near-infrared bands. Spectral resolution reached down to nanometer scales, enabling astronomers to detect subtle changes in chemical signatures as the comet approached the Sun.

Orbital Coordination: Space Meets Earth

Precision increased dramatically once platforms began exchanging telemetry. NASA’s Deep Space Network (DSN) relayed data not only from spacecraft but also supported calculations for real-time orbital updates. ESA’s Space Situational Awareness program supplemented this with collision-avoidance monitoring, although 3I/ATLAS posed no threat.

This hybrid infrastructure—satellites above and observatories below—gave researchers uninterrupted coverage. Continuous tracking allowed high-temporal resolution measurements, essential for capturing activity cycles like tail development and nucleus brightening.

Astrophotographers and Citizen Scientists: A Growing Role

As in past cosmic events, amateur astronomers worldwide contributed valuable supplementary data. Using DSLR cameras mounted on equatorial-tracking rigs, many recorded time-lapse sequences and high-resolution frames that validated motion and structure seen in institutional feeds. In clear atmospheric windows, some amateurs even captured transient flare-ups, prompting larger observatories to re-target swiftly.

These community efforts, coordinated through platforms like the International Astronomical Union’s Minor Planet Center, added observational density that improved modeling precision. Crowd-sourced frames filled geographic and temporal gaps, providing a nearly continuous observational footprint during key periods of the flyby window.

With each detection and data point, the instruments observing 3I/ATLAS collectively form a digital tapestry—one that captures not only the raw physicality of the interstellar visitor but also the collaborative prowess of 21st-century astronomy.

How the Comet is Studied: From Solar System to Deep Space

Tracking Motion Across the Solar System

The path of 3I/ATLAS is dynamically hyperbolic, which confirms its interstellar origin. Unlike comets bound to the Sun in elliptical orbits, this one approaches on a one-time trajectory through the solar system. Observatories trace its motion using precise astrometric data, measuring its position relative to background stars. This allows teams at NASA's Jet Propulsion Laboratory and ESA's Near-Earth Object Coordination Centre to calculate its velocity, curvature, and escape trajectory.

3I/ATLAS is moving at a heliocentric velocity exceeding 60,000 kilometers per hour (about 37,300 miles per hour). Its direction, not aligned with the ecliptic plane, offers additional evidence of its alien origin. Time-resolved observations conducted over weeks capture the nuances of its motion—small shifts that evolve due to gravitational tugs from planets and radiation pressure from the Sun.

Solar Radiation and Its Effects on Interstellar Material

As 3I/ATLAS passes through the inner solar system, it interacts with solar wind, UV radiation, and charged particles—forces it has never encountered in interstellar space. These interactions cause surface heating, outgassing of volatile compounds, and the development of a transient coma and tail.

Using spectrometers aboard space-based telescopes such as ESA's Solar Orbiter and NASA’s SOHO, researchers monitor ionized gases released from the nucleus. The chemical composition differs from that of solar system comets, showing a higher ratio of carbon monoxide relative to water vapor. These differences hint at chemical processes in cold interstellar environments, where ices condense differently and radiation exposure is lower.

Planetary Comparisons and Martian Observations

Infrared instruments on Mars-based missions like MAVEN (Mars Atmosphere and Volatile EvolutioN) observe 3I/ATLAS from a perspective not possible on Earth. As the comet nears Mars’s orbital path, cross-analysis with Martian atmospheric data allows scientists to discern how 3I/ATLAS’s volatiles would interact with a planetary magnetosphere or thin atmosphere.

These comparisons refine models for early planetary chemistry. If organic compounds from interstellar sources seeded early Mars, similar observations now offer analog environments. Mars’s location provides a possible in-transit snapshot of cometary emissions before they are further altered near the Sun.

What Lies Beyond the Solar System: Probing the Origins of Interstellar Matter

Every data point collected from 3I/ATLAS—its molecular makeup, dust plume structure, nucleus albedo—feeds directly into models of star system formation beyond our own. Unlike solar comets shaped by a common protoplanetary disc, 3I/ATLAS formed around a distant star with distinct conditions. The presence of complex molecules, or lack thereof, helps constrain the physical conditions of its origin.

Using ultraviolet and submillimeter wavelengths, telescopes like the James Webb Space Telescope (JWST) pierce the coma to reveal material preserved for billions of years. This material holds signatures of its birth environment—potentially a protoplanetary disc around an M-dwarf or even remnants from a planet-forming region disrupted by stellar migration. No mission has returned samples from interstellar origins, but spectral data from 3I/ATLAS bridges that gap.

What can one icy traveler teach us about other stars and their planets? The comet's brief presence offers rare, high-resolution insights into the cosmic processes that extend far beyond the gravitational reach of our Sun.

Unlocking the Secrets of 3I/ATLAS: The Crucial Role of Space Missions and Observatories

Global Space Agencies at the Helm: NASA and ESA Missions

NASA and the European Space Agency (ESA) have deployed a suite of missions tailored to study transient cosmic visitors like 3I/ATLAS. These missions offer more than observational capabilities—they provide real-time data across wavelengths, unlocking layers of insight into interstellar objects.

• James Webb Space Telescope (JWST): With unmatched sensitivity in the infrared spectrum, JWST enables detailed compositional analysis of 3I/ATLAS's coma and nucleus. Spectroscopic readings reveal volatile materials and isotopic ratios absent from Solar System-born comets.
• ESA’s Hera mission: Although primarily focused on asteroid systems, Hera includes instruments suitable for adaptive deployment in interstellar object surveillance, offering context on gravitational interactions and trajectory modeling when such bodies enter the inner Solar System.
• Solar and Heliospheric Observatory (SOHO): Operating jointly under ESA and NASA, SOHO tracks interactions between solar winds and the comet’s tail. Its LASCO coronagraphs provide continuous visibility when ground-based observatories lose daylight coverage.

Space Telescopes Deliver High-Fidelity Observations

Telescopic platforms stationed in orbit bypass atmospheric distortion—a constraint that limits ground-based resolution. These observatories function as precision tools for tracking motion and capturing rare spectral fingerprints emitted by 3I/ATLAS.

• Imaging: Space telescopes aboard platforms like JWST or Hubble acquire high-resolution visuals down to sub-kilometer surface features. This level of detail makes it possible to detect surface outgassing vents or irregular topography.
• Spectroscopy: By breaking apart the comet’s emitted light into its constituent spectra, researchers measure elemental composition and temperature variations, identifying molecules such as CO, CO₂, and H₂O ice sublimating off the nucleus.
• Motion Tracking: Spaceborne optical sensors precisely resolve the position of 3I/ATLAS over time. These data enhance dynamical models used to determine the comet’s ultimate origin and trajectory through the galaxy.

Coordinated International Monitoring and Data Exchange

Tracking an interstellar object demands unified strategy. Independent siloed observations would miss key phenomena. Instead, institutions across continents operate within a framework of synchronized tagging, cross-verification, and live data feeds.

The International Astronomical Union (IAU) facilitates observation coordination via Central Bureau for Astronomical Telegrams (CBAT), which circulates time-sensitive updates worldwide. Data sets from mission payloads and telescopes funnel into repositories like NASA’s Planetary Data System (PDS) and ESA’s Planetary Science Archive (PSA), allowing astronomers in Tokyo, Cape Town, and Munich to analyze identical frames using their own algorithms.

This structured collaboration ensures that every phase of 3I/ATLAS’s Earthward journey—from deep space ingress to sunlight-driven metamorphosis—is archived, studied, and collectively understood. Without an integrated observational approach, significant discoveries would remain disconnected or entirely unnoticed.

Bringing the Cosmos Closer: Public Engagement & Cosmic Discoveries

As images of the interstellar comet 3I/ATLAS continue to spark scientific interest, they also ignite public imagination. NASA and ESA have prioritized making this extraordinary event accessible to a global audience, not just through official data releases, but also by turning complex astronomy into engaging, immersive experiences for people of all backgrounds.

Turning Data into Experience: Outreach by NASA and ESA

Both agencies released a series of multimedia tools to visually narrate 3I/ATLAS’s journey. These include:

• 3D Renders: High-resolution, rotational models created from actual trajectory and imaging data, providing a dynamic look at the comet's structure and motion.
• Visual Teasers: Edited video segments combining space imagery, scientific infographics, and animations to portray the comet's approach and origin story beyond the solar system.
• Interactive Portals: Web-based platforms allow users to visualize the comet’s path in real time based on coordinates updated daily from tracking observatories.

View the Comet with Your Own Eyes

You don't need a professional observatory to track 3I/ATLAS. With its approach nearing optimal visibility, amateur astronomers can locate the comet using widely available telescopes. Several stargazing apps—Skysafari, Star Walk 2, and Stellarium—have already integrated its projected path. GPS-synced notifications help users plan viewings based on their location and the night sky’s conditions.

From suburban backyards to dark-sky reserves, the comet presents a rare chance to visually connect with an object that originated in another star system. It’s not just about seeing it—it’s about understanding that what you’re looking at once drifted light-years away from Earth.

Learning Beyond the Classroom

Space agencies are partnering with educational networks to bring 3I/ATLAS into classrooms. Student-led observatory sessions, livestreams with astronomers, and downloadable learning kits transform this once-in-a-lifetime event into a collective educational moment. Teachers can access curriculum-enhanced modules covering light spectra, motion physics, and the origins of interstellar bodies, using 3I/ATLAS as a real-time case study.

Citizen science programs also play a key role. NASA’s "Eyes on the Solar System" platform and ESA’s Comet Chasers initiative invite the public to analyze imagery, contribute observations, and even propose naming features on the comet’s surface. Data submitted through these programs feeds back into mission archives, sometimes flagging anomalies the core teams re-investigate.

Where do you stand in the vast dialogue between humanity and the stars? With 3I/ATLAS drawing closer every night, now is the time to engage and explore.

The Future Rewritten in Ice and Dust: Implications of the 3I/ATLAS Discovery

Studying Interstellar Comets Redefines Our Place in the Cosmos

3I/ATLAS isn’t just another celestial visitor—it’s a scientific milestone. As the third confirmed interstellar comet, its origin beyond our solar system transforms it into a natural probe from another star. Unlike comets born from the Kuiper Belt or Oort Cloud, 3I/ATLAS carries the chemical fingerprints and structural signatures of an alien solar environment. By dissecting these markers through spectroscopic data, astronomers gain unfiltered access to the building blocks of other planetary systems.

This matters. Direct sampling of exoplanetary matter remains beyond current technology. But comets like 3I/ATLAS act as emissaries of that unreachable terrain. Detailed analysis gives researchers concrete models of how materials form, aggregate, and evolve across the galactic neighborhood.

Unprecedented Insights Into Solar System Formation

Comparative studies between 3I/ATLAS and native solar comets unlock insights into our system’s birth. Variations in isotopic ratios of hydrogen, oxygen, and carbon point to differences in nebular temperatures and stellar radiation levels during formation. NASA's updated high-resolution images, along with ESA's infrared spectrometry data, help trace volatiles such as water ice and carbon monoxide—chemicals critical to life and planetary chemistry.

Researchers have observed through signals captured across multiple telescopes that some molecules in 3I/ATLAS exist in crystalline forms not typically seen in our native comets. This suggests drastically different thermal conditions—a clue to how other star systems synthesize complex organic matter. Such specific compositions inform planet-formation models, accelerating our roadmap to understanding how Earth, Mars, and potentially habitable exoplanets came into existence over 4.6 billion years ago.

Driving Investment in Advanced Viewing and Data Technologies

The sharp detail captured in the teaser images circulated by NASA and ESA stems from next-generation optics and AI-driven data reconstruction. Public engagement spikes during such cosmic events, boosting funding justification for flagship missions like the Nancy Grace Roman Space Telescope and ESA's Ariel observatory. The success of tracking interstellar targets with instruments optimized for solar system science signals a shift—a demand to expand the sensitivity and coverage of observational arrays.

Expect allocations toward wider-field infrared sensors, machine-learning algorithms for trajectory prediction, and faster data transmission interfaces. Astronomical institutions aren’t only looking deeper; they're also gearing systems to adapt in real time, ensuring fleeting phenomena like interstellar comets don’t escape undetected.

Transforming How Deep Space Science Gets Done

The 3I/ATLAS event validates how autonomous AI support, multi-satellite synchronization, and large-scale citizen science collaborations can work in concert. Space isn’t being explored solely through traditional telescopes anymore. Layered data pipelines—from high-orbit observatories to backyard imaging networks—generate a more holistic picture of these cosmic travelers.

This is no longer just the age of observing the cosmos. It’s an age of decoding it—pixel by pixel, molecule by molecule, streamlining the way planetary systems beyond our own come into focus. Every interstellar comet narrows the gap between astronomical theory and empirical evidence, remixing how astronomers model, detect, and ultimately understand the architecture of the universe.