If a star located 30 light years away from Earth were to go nova, the effects on our planet would depend on various factors such as the size of the star, its distance, and the specific properties of the nova event.
A nova occurs when a white dwarf star in a binary system pulls matter from its companion star, causing a sudden increase in brightness. While novae can be very bright, they are not as cataclysmic as supernovae, which involve the complete destruction of a star.
Given that the star is 30 light years away, it means that the light from the nova event would take 30 years to reach Earth. So, if the star went nova today, we would not observe the event until 30 years later. When the light finally reaches us, it would appear as a sudden increase in brightness in the direction of that star.
However, in terms of direct physical effects on Earth, the distance of 30 light years is significant enough that the nova event itself would not pose a direct threat to our planet. The energy released in a nova would be spread out over a large distance, and the effects on Earth would be minimal.
Nonetheless, depending on the intensity of the nova, it's possible that the sudden increase in brightness could be visible to the naked eye, much like a particularly bright and distant celestial event. Astronomers would certainly take note of such an event and study it in detail.
In summary, while a nova occurring in a star 30 light years away would be an interesting and potentially spectacular event for astronomers, it would not have any significant direct consequences or pose any immediate danger to Earth or its inhabitants.