Objects can hide in plain sight, orbiting in the Sun's shadow
En los márgenes del resplandor solar, donde la luz del astro rey oculta tanto como revela, los astrónomos han hallado un visitante considerable: un asteroide de 700 metros que orbita más cerca del Sol que Venus, completando su vuelta en apenas 128 días. El descubrimiento de 2025 SC79 nos recuerda que el sistema solar aún guarda secretos en sus rincones más luminosos, y que la vigilancia del cielo no es un ejercicio académico, sino una forma de prudencia civilizatoria. Lo que no podemos ver puede, en efecto, hacernos daño.
- Un asteroide del tamaño suficiente para devastar un continente entero orbitaba oculto en el resplandor solar, invisible para la mayoría de los telescopios del mundo.
- La ventana para detectarlo era de apenas minutos cada noche: ese instante frágil del crepúsculo en que el cielo oscurece lo justo para que un telescopio en Chile pudiera atraparlo.
- Solo existe otro objeto conocido que orbite completamente dentro de la trayectoria de Venus, lo que convierte a 2025 SC79 en una rareza orbital sin precedentes casi absolutos.
- Varios observatorios confirmaron rápidamente tanto su existencia como su trayectoria, descartando por ahora un impacto inminente, pero subrayando la urgencia de mejorar los métodos de detección.
- La pregunta ya no es si existen más asteroides ocultos en la zona ciega del Sol, sino cuántos han pasado ya cerca de la Tierra sin que nadie los viera.
El Sol, fuente de toda vida en la Tierra, también actúa como cómplice involuntario de los objetos que se ocultan en su resplandor. Los llamados asteroides crepusculares solo se dejan ver durante breves minutos al amanecer o al atardecer, cuando la luz solar retrocede lo suficiente para que los telescopios puedan escudriñar esa zona prohibida del cielo. Es en esas ventanas fugaces donde los astrónomos libran una carrera silenciosa contra el tiempo.
Este octubre, esa carrera produjo un hallazgo notable. El astrónomo Scott S. Sheppard, valiéndose de la Dark Energy Camera instalada en Chile, descubrió el asteroide 2025 SC79, una roca de 700 metros cuyo impacto contra la Tierra desencadenaría una catástrofe de escala continental. Otros observatorios, entre ellos Gemini y Magellan, confirmaron tanto su existencia como su órbita, descartando por ahora cualquier amenaza inmediata.
Lo que hace verdaderamente singular a este objeto es su trayectoria. Pertenece a los asteroides Atira, un grupo de apenas 39 miembros conocidos cuyas órbitas transcurren íntegramente dentro de la de la Tierra. Pero 2025 SC79 va más lejos: es solo el segundo objeto jamás detectado que orbita completamente dentro de la trayectoria de Venus, completando una vuelta al Sol en 128 días, el tercer período orbital más rápido registrado para un asteroide.
Su descubrimiento tardío, pese a su tamaño considerable, plantea una pregunta incómoda: ¿cuántos objetos similares siguen ahí fuera, desconocidos, orbitando en la penumbra del astro que nos da la vida? Mejorar los métodos de detección en la zona cercana al Sol ya no es solo un desafío científico; es, cada vez más, una necesidad planetaria.
The Sun gives us life, but its blinding glare also shields cosmic threats from view. Somewhere in that radiance, hidden asteroids drift through space—objects so close to our star that they reveal themselves only in the narrow windows of twilight, those brief moments after sunset or before dawn when the sky darkens just enough for telescopes to catch a glimpse. Astronomers race against these fleeting minutes, trying to map the solar system's most elusive neighbors before one of them finds its way toward Earth.
This October, that hunt yielded something remarkable: a 700-meter asteroid designated 2025 SC79, discovered by astronomer Scott S. Sheppard using the Dark Energy Camera mounted in Chile. The rock is massive enough that a direct collision with Earth would trigger a continental catastrophe—not a certainty, but a possibility serious enough that scientists track such objects with genuine concern. Other observatories, including the Gemini and Magellan telescopes, quickly confirmed both the asteroid's existence and its trajectory.
What makes 2025 SC79 extraordinary is not just its size but its orbit. It belongs to an exclusive group called Atira asteroids, a club of only 39 known members whose paths lie entirely within Earth's orbit around the Sun. This alone makes them nearly invisible to conventional surveillance—they spend most of their time in the blind spot created by our own planet's position. But 2025 SC79 goes further still. It is only the second known object ever detected that orbits entirely within Venus's path, traveling so close to the Sun that it completes a full circuit in just 128 days, the third-fastest orbital period ever recorded for an asteroid.
These twilight asteroids, as astronomers call them, present a unique challenge. Because they orbit so near the Sun, they can only be observed during the brief window when the Sun has dipped below the horizon but its light still floods the sky. Miss that window, and the asteroid vanishes into the glare for weeks or months. It is a race against the clock, night after night, with the stakes being nothing less than early warning of a potential planetary threat.
The discovery of 2025 SC79 underscores how much of the solar system still remains hidden from us. For all our telescopes and satellites, objects can hide in plain sight, orbiting in the Sun's shadow, unknown and untracked. The fact that this particular asteroid went undetected until now, despite its considerable size, suggests that others like it may still be out there, waiting to be found. As detection methods improve and astronomers develop new strategies for observing near-Sun space, the question becomes not whether we will find more twilight asteroids, but how many have already passed through our cosmic neighborhood unnoticed.
Citas Notables
The asteroid's dimensions are considerable, large enough to trigger a continental catastrophe in the unlikely but not impossible event of impact with Earth.— La Razón reporting on 2025 SC79
La Conversación del Hearth Otra perspectiva de la historia
Why does the Sun's glare make these asteroids so hard to find? Isn't that just a matter of better equipment?
It's not really about equipment power—it's about geometry. When an object orbits very close to the Sun, it's always in the Sun's direction from Earth. You can't observe it when the Sun is up because the glare overwhelms any telescope. You can only look during twilight, those few minutes when the Sun is below the horizon but still lighting the sky. That window closes fast.
So astronomers have maybe ten or fifteen minutes a night to spot these things?
Sometimes less. And the asteroid has to be in the right part of its orbit at the same time. You might have clear skies, the right equipment, and still miss it because the geometry isn't aligned. That's why finding 2025 SC79 is significant—it suggests there's a whole population of these objects we haven't catalogued yet.
If this asteroid is only the second one known to orbit inside Venus's path, how many Atira asteroids do we think actually exist?
That's the unsettling part. We've found 39 confirmed Atira asteroids, but the actual number could be much higher. These objects are inherently difficult to detect. We're probably seeing only a fraction of what's really out there.
And if one of them hit Earth?
At 700 meters across, 2025 SC79 would release energy equivalent to thousands of nuclear weapons. The impact zone would be devastated, and the dust and debris would affect the climate globally. It wouldn't end civilization, but it would reshape it.
Does this asteroid pose an immediate threat?
No. Its orbit is well-understood now, and the calculations show no collision risk for centuries, if ever. But the discovery itself is a reminder that we're still learning what's in our own backyard.