Would it be possible to see electric lights on distant planets using current telescopes?
No. There are very few exoplanets that can even be imaged as "dots". There are none that can be resolved as discs and it would be well beyond current technology to see lights on the surface of an Earth-like planet.
Most exoplanets are only known from periodic dimming of a star as the planet passes in front of its star, or wobbles in a star's motion, as the planet's gravity causes the star to move forward and back.
We could see lights on Mars, if they existed as they do on Earth, but they don't.
I did a few rough calculations.
Let's assume a neighbor system (4 light years), and a population of 1 billion people each transmitting 1000W of light into the night sky.
Then on Earth, a 100 square meters telescope would receive about 2 photons per minute from the electric lights. This is far beyond current technology, especially as there are much, much brighter sources in very close vicinity.
No, at least not with currently deployed telescopes. However, it is theoretically possible with current (or near future) technology. We could potentially image the lights of an exoplanet using a Solar Gravitational Lens (SGL), as is currently under consideration by the NASA Institute for Advanced Concepts as a "Phase II" program. "Phase II" is described as signifying that NASA has:
determined that much of the foundational technology exists or is in intermediate levels of readiness due to the proliferation of government and commercial smallsat programs.
The technique works the same as we normally observe gravitational lensing. That is, the light of a distant object is concentrated in a narrow region of space called a focal line by a massive object between the observer and the lensed object. This lensing dramatically increases the resolution and apparent brightness of the observed object, enabling us to see things that are too far away or too dim for us to directly observe with conventional telescopes.
A SGL mission would send probes so that they place the Sun between the probe and the exoplanet. By blocking out the light of the sun, the probe could observe the Einstein Ring of the exoplanet surrounding the Sun. This ring could be reconstructed into a traditional image to view the surface of the exoplanet, such as this simulated image.
At this resolution (estimated by NASA as being up to ~25 km-scale surface resolution for an Earth sized exoplanet at 30 pc), it would be possible to directly observe lights of an advanced alien civilization.
Here there was only sludge, microbial mats and goop for 1.5 billion years, then it was filaments, small specs and sludge for 1.5 billion years, and there has been light for 50 years, and even those look like a volcano or a reflection of moons and stars onto clouds or ice.
i.e. Venus because of it's clouds reflects more than 4 times as much incoming light than the moon, and more than twice of the Earth's.
So astronomers want to detect chemicals rather than lights, we don't know what alien light bulbs use for chemistry, however we can measure high oxygen content on another planet, which means photosynthesis. Planet Rarth's oxygen started rising about 1000 million years ago at the same time as life-form size was rising.
We need hypersensitive instruments for that.
Freeman Dyson postulated an industrial society could be detected on Infrared. Like Earth looking for heat islands in urban areas.
Another would periodic spikes in infrared waves from stars because society was tapping its power.
We could detect but it really depends on the distance you're talking about
Not using current technology (if the distance is huge). The Solar Gravitational lensing mission could do detect city lights from exoplanets but a mass (like a galaxy, neutron star and blackhole) would be required (which also most probably would be available).
If the distance is too far away according to the inverse square law the light's intensity would get smaller to a limit where we can't really detect it.
Because of the Doppler shift it would be tougher because the redshift created from the effect would be huge if the distance is huge as per Hubble law but that is kind of manageable because we even have radio telescopes. But one of the most powerful telescopes we have ever made the JWST has the mid-infrared ranges ( 5-28.5 μm) but doppler shift could extend even farther as per the distance so it's a catch 22 situation if we want to see large distances then we would have encounter more redshift too.
We wouldn't see the lights if the planet/asteroid is in the zone of avoidance
Also since different elements (in the Periodic table) in Bulbs emit different Wavelengths of light we're not sure which wavelength to focus on like Argon, Xenon, Incandescent (Tungsten)!
The amount of light emmited is based on the energy usage given by the Karshadev scale
Hope it helps, Thanks