A spaceship of proper length \(\ell=100 \mathrm{~m}\) travels in the positive \(x\) direction at a speed of \(0.800 c_{0}\) relative to Earth. An identical spaceship travels in the negative \(x\) direction along a parallel course at the same speed relative to Earth. At \(t=0\), an observer on Earth measures a distance \(d=50,000 \mathrm{~km}\) separating the two ships. At what instant does this observer see the leading edges of the two ships pass each other?